Catalyst 2950 Desktop Switch Command Reference, 12.0(5.2)WC(1)
Cisco IOS Commands
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Cisco IOS Commands

Table Of Contents

Cisco IOS Commands

abort

apply

clear ip address

clear mac-address-table

clear vtp counters

cluster commander-address

cluster discovery hop-count

cluster enable

cluster holdtime

cluster management-vlan

cluster member

cluster run

cluster setup

cluster standby-group

cluster timer

delete

duplex

enable last-resort

enable use-tacacs

exit

flowcontrol

interface

ip address

ip igmp snooping

ip igmp snooping vlan

ip igmp snooping vlan immediate-leave

ip igmp snooping vlan mrouter

ip igmp snooping vlan static

login

login authentication

mac-address-table aging-time

mac-address-table secure

mac-address-table static

management

ntp access-group

ntp authenticate

ntp authentication-key

ntp broadcast client

ntp broadcastdelay

ntp broadcast destination

ntp broadcast key

ntp broadcast version

ntp clock-period

ntp disable

ntp max-associations

ntp peer

ntp server

ntp source

ntp trusted-key

port group

port monitor

port protected

port security

port storm-control

rcommand

reset

rmon collection stats

show changes

show cluster

show cluster candidates

show cluster members

show current

show env

show file systems

show interface

show ip igmp snooping

show ip igmp snooping mrouter

show mac-address-table

show mac-address-table multicast

show ntp associations

show ntp status

show port group

show port monitor

show port protected

show port security

show port storm-control

show proposed

show rps

show spanning-tree

show tacacs

show udld

show version

show vlan

show vtp

show wrr-queue bandwidth

show wrr-queue cos-map

shutdown

shutdown vlan

snmp-server enable traps vlan-membership

snmp-server enable traps vtp

snmp-server host

spanning-tree

spanning-tree cost

spanning-tree forward-time

spanning-tree hello-time

spanning-tree max-age

spanning-tree portfast

spanning-tree port-priority

spanning-tree priority

spanning-tree protocol

spanning-tree rootguard

spanning-tree uplinkfast

speed

switchport access

switchport mode

switchport priority

switchport trunk allowed vlan

switchport trunk native

tacacs-server attempts

tacacs-server directed-request

tacacs-server dns-alias-lookup

tacacs-server extended

tacacs-server host

tacacs-server key

tacacs-server last-resort

tacacs-server login-timeout

tacacs-server optional-passwords

tacacs-server retransmit

tacacs-server timeout

udld

udld enable

udld reset

vlan

vlan database

vtp

vtp domain

vtp file

vtp password

vtp v2-mode

wrr-queue bandwidth

wrr-queue cos-map


Cisco IOS Commands


abort

Use the abort VLAN database command to abandon the proposed new VLAN database, exit VLAN database mode, and return to privileged EXEC mode.

abort

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If you have added, deleted, or modified VLAN parameters in VLAN database mode but you do not want to keep the changes, the abort command causes all the changes to be abandoned. The VLAN configuration that was running before you entered VLAN database mode continues to be used.

Examples

The following example shows how to abandon the proposed new VLAN database and exit to the privileged EXEC mode:

Switch(vlan)# abort
Switch#

You can verify that no VLAN database changes occurred by entering the show vlan brief command in privileged EXEC mode.

Related Commands

Command
Description

apply

Implements the proposed new VLAN database, increments the database configuration revision number, propagates it throughout the administrative domain, and remains in VLAN database mode.

exit

Implements the proposed new VLAN database, increments the database configuration number, propagates it throughout the administrative domain, and returns to privileged EXEC mode.

reset

Abandons the proposed VLAN database and remains in VLAN database mode. Resets the proposed database to the currently implemented VLAN database on the switch.

show vlan

Displays the parameters for all configured VLANs in the administrative domain.

shutdown vlan

Shuts down (suspends) local traffic on the specified VLAN.

vlan database

Enters VLAN database mode from the command-line interface (CLI).


apply

Use the apply VLAN database command to implement the proposed new VLAN database, increment the database configuration revision number, propagate it throughout the administrative domain, and remain in VLAN database mode.

apply

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The apply command implements the configuration changes you made after you entered VLAN database mode and uses them for the running configuration. This command keeps you in VLAN database mode.

You cannot use this command when the switch is in the VLAN Trunk Protocol (VTP) client mode.

Examples

The following example shows how to implement the proposed new VLAN database and recognize it as the current database:

Switch(vlan)# apply

You can verify that VLAN database changes occurred by entering the show vlan command in privileged EXEC mode.

Related Commands

Command
Description

apply

Implements the proposed new VLAN database, increments the database configuration revision number, propagates it throughout the administrative domain, and remains in VLAN database mode.

exit

Implements the proposed new VLAN database, increments the database configuration number, propagates it throughout the administrative domain, and returns to privileged EXEC mode.

reset

Abandons the proposed VLAN database and remains in VLAN database mode. Resets the proposed database to the currently implemented VLAN database on the switch.

show vlan

Displays the parameters for all configured VLANs in the administrative domain.

shutdown vlan

Shuts down (suspends) local traffic on the specified VLAN.

vlan database

Enters VLAN database mode from the command-line interface (CLI).


clear ip address

Use the clear ip address privileged EXEC command to delete an IP address for a switch without disabling the IP processing.

clear ip address [vlan vlan-id]

Syntax Description

vlan vlan-id

(Optional) Delete an IP address only within the specified VLAN.
Valid IDs are from 1 to 1001; do not enter leading zeroes.


Defaults

No IP address is defined for the switch.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

A switch can have one IP address.

The IP address of the switch can be accessed only by nodes connected to ports that belong to the management VLAN. By default, the management VLAN is VLAN 1, but you can configure a different VLAN as the management VLAN.

If your switch receives its IP address from a Bootstrap Protocol (BOOTP) or a Dynamic Host Configured Protocol (DHCP) server and you clear the switch IP address by using the clear ip address command, the BOOTP or DHCP server reassigns the IP address.

Examples

The following example shows how to clear the IP address for the switch on VLAN 1:

Switch# clear ip address vlan 1

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the configuration information currently running on the switch.


clear mac-address-table

Use the clear mac-address-table privileged EXEC command to delete entries from the MAC address table.

clear mac-address-table [static |secure] [address hw-addr] [interface interface]
[vlan vlan-id]

Syntax Description

static

(Optional) Delete only static addresses.

secure

(Optional) Delete only secure addresses.

address hw-addr

(Optional) Delete the address hw-addr of type static, dynamic, and secure as specified.

interface interface

(Optional) Delete an address on the interface interface of type static, dynamic, or secure as specified.

vlan vlan-id

(Optional) Delete all the MAC addresses for vlan-id. Valid IDs are from
1 to 1001; do not enter leading zeroes.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command deletes entries from the global MAC address table. Specific subsets can be deleted by using the optional keywords and values. If more than one optional keyword is used, all of the conditions in the argument must be true for that entry to be deleted.

Examples

The following example shows how to delete static addresses on port fa0/7:

Switch# clear mac-address-table static interface fa0/7

The following example shows how to delete all secure addresses in VLAN 3:

Switch# clear mac-address-table secure vlan 3

The following example shows how to delete address 0099.7766.5544 from all ports in all VLANs. If the address exists in multiple VLANs or multiple ports, all the instances are deleted.

Switch# clear mac-address-table address 0099.7766.5544

The following example shows how to delete address 0099.7766.5544 only in VLAN 2:

Switch# clear mac-address-table address 0099.7766.5544 vlan 2




You can verify the previous commands by entering the show mac-address-table command in privileged EXEC mode.

Related Commands

Command
Description

show mac-address-table

Displays the MAC address table.


clear vtp counters

Use the clear vtp counters privileged EXEC command to clear the VLAN Trunk Protocol (VTP) and pruning counters.

clear vtp counters

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Examples

The following example shows how to clear the VTP counters:

Switch# clear vtp counters

You can verify the previous command by entering the show vtp counters command in privileged EXEC mode.

Related Commands

Command
Description

show vtp counters

Display general information about the VTP management domain, status, and counters.


cluster commander-address

The command switch automatically provides its MAC address to member switches when these switches join the cluster. The member switch adds this information and other cluster information to its running configuration file. You do not need to enter this command. Enter the no form of this global configuration command on a member switch to remove it from a cluster only during debugging or recovery procedures.

cluster commander-address mac-address member number name name

no cluster commander-address

default cluster commander-address

Syntax Description

mac-address

MAC address of the cluster command switch.

member number

Number of member switch. The range is from 0 to 15.

name name

Name of the cluster up to 31 characters.

no

Remove a switch from the cluster. Entered on the member switch.

default

Remove a switch from the cluster. Entered on the member switch.


Defaults

The switch is not a member of any cluster.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

A cluster member can have only one command switch.

The member switch retains the identity of the command switch during a system reload by using the mac-address parameter.

You can enter the no form on a member switch to remove it from the cluster only during debugging or recovery procedures. However, with normal switch configuration, we recommend that you remove member switches only by entering the no cluster member n command on the command switch.

When a standby command switch becomes active, it removes the cluster commander-address line from its configuration.

Examples

The following is sample text from the running configuration of a cluster member.

Switch(config)# cluster commander-address 00e0.9bc0.a500 member 4 name my_cluster

The following example shows how to remove a member from the cluster by using the cluster member console.

Switch-es3# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Switch-es3(config)# no cluster commander-address

You can verify the previous command by entering the show cluster command in user EXEC mode.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster discovery hop-count

Use the cluster discovery hop-count global configuration command on the command switch to set the hop-count limit for extended discovery of candidate switches. Use the no form of this command to set the hop count to the default value.

cluster discovery hop-count number

no cluster discovery hop-count

default cluster discovery hop-count

Syntax Description

number

Number of hops from the cluster edge that the command switch limits the discovery of candidates. The range is from 1 to 7.

no

Set the hop count to the default value (3).

default

Set the hop count to the default value (3).


Defaults

The hop count is set to 3.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Enter this command only on the command switch. This command does not operate on member switches.

If the hop count is set to 1, it disables extended discovery. The command switch discovers only candidates that are one hop from the edge of the cluster. The edge of the cluster is the point between the last discovered member switch and the first discovered candidate switch.

Examples

The following example shows how to set hop count limit to 4. This command is executed on the command switch.

Switch(config)# cluster discovery hop-count 4

You can verify the previous command by entering the show cluster command in user EXEC mode.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show cluster candidates

Displays a list of candidate switches.


cluster enable

Use the cluster enable global configuration command on a command-capable switch to enable it as the cluster command switch, assign a cluster name, and optionally assign a member number to it. Use the no form of the command to remove all members and make the command switch a candidate switch.

cluster enable name [command-switch-member-number]

no cluster enable

default cluster enable

Syntax Description

name

Name of the cluster up to 31 characters. Valid characters include only alphanumerics, dashes, and underscores.

command-switch-member-number

(Optional) Assign a member number to the command switch of the cluster. The range is from 0 to 15.

no

Remove all member switches and make the command switch a candidate.

default

Switch is not a command switch.


Defaults

The switch is not a command switch.

No cluster name is defined.

The member number is 0 when this is the command switch.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command runs on any command-capable switch that is not part of any cluster. This command fails if a device is already configured as a member of the cluster.

You must name the cluster when you enable the command switch. If the switch is already configured as the command switch, this command changes the cluster name if it is different from the previous name.

Examples

The following example shows how to enable the command switch, name the cluster, and set the command switch member number to 4.

Switch(config)# cluster enable Engineering-IDF4 4

You can verify the previous command by entering the show cluster command in user EXEC mode on the command switch.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster holdtime

Use the cluster holdtime global configuration command on the command switch to set the duration in seconds before a switch (either the command or member switch) declares the other switch down after not receiving heartbeat messages. Use the no form of this command to set the duration to the default value.

cluster holdtime holdtime-in-secs

no cluster holdtime

default cluster holdtime

Syntax Description

holdtime-in-secs

Duration in seconds before a switch (either a command or member switch) declares the other switch down. The range is from 1 to 300 seconds.

no

Set the holdtime to the default value (80 seconds).

default

Set the holdtime to the default value (80 seconds).


Defaults

The holdtime is 80 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command with the cluster timer global configuration command only on the command switch. The command switch propagates the values to all its cluster members.

The holdtime is typically set as a multiple of the interval timer (cluster timer). For example, it takes (holdtime-in-secs divided by interval-in-secs) number of heartbeat messages to be missed in a row to declare a switch down.

Examples

The following example shows how to change the interval timer and the duration on the command switch.

Switch(config)# cluster timer 3
Switch(config)# cluster holdtime 30

You can verify the previous commands by entering the show cluster command in user EXEC mode.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster management-vlan

Use the cluster management-vlan global configuration command on the command switch to change the management VLAN for the entire cluster. Use the no form of this command to change the management VLAN to VLAN 1.

cluster management-vlan n

no cluster management-vlan

default cluster management-vlan

Syntax Description

n

VLAN ID of the new management VLAN. Valid VLAN IDs are from 1 to 1001.

no

Set the management VLAN to VLAN 1.

default

Set the management VLAN to VLAN 1.


Defaults

The default management VLAN is VLAN 1.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Enter this command only on the command switch.

This command is not written to the configuration file.

Examples

The following example shows how to change the management VLAN to VLAN 5 on the entire cluster.

Switch(config)# cluster management-vlan 5

You can verify the previous command by entering the show interface vlan number command in privileged EXEC mode.

Related Commands

Command
Description

management

Shuts down the current management VLAN interface and enables the new management VLAN interface on an individual switch.


cluster member

Use the cluster member global configuration command on the command switch to add members to a cluster. Use the no form of the command to remove members from the cluster.

cluster member [n] mac-address H.H.H [password enable-password]

no cluster member n

default cluster member n

Syntax Description

n

(Optional) The number that identifies a cluster member. The range is from 0 to 15.

mac-address H.H.H

MAC address of the member switch in hexadecimal format.

password enable-password

Enable password of the candidate switch. The password is not required if there is no password on the candidate switch.

no

Remove the specified member from the cluster.

default

Remove the specified member from the cluster.


Defaults

A newly enabled command switch has no associated cluster members.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Enter this command only on the command switch to add a member to or remove a member from the cluster. If a switch is not commanding a cluster, this command displays an error message.

You do not need to enter a member number. The command switch selects the next available member number and assigns it to the switch joining the cluster.

You must enter the enable password of the candidate switch for authentication when it joins the cluster. The password is not saved in the running or startup configuration. After a candidate switch becomes a member of the cluster, its password becomes the same as the command-switch password.

If a switch does not have a configured host name, the command switch appends a member number to the command-switch host name and assigns it to the member switch.

Examples

The following example shows how to add a switch as member 2 with MAC address 00E0.1E00.2222 and the password grandkey to a cluster.

Switch(config)# cluster member 2 mac-address 00E0.1E00.2222 password grandkey

The following example shows how to add a switch with MAC address 00E0.1E00.3333 to the cluster. The command switch selects the next available member number and assigns it to the switch joining the cluster.

Switch(config)# cluster member mac-address 00E0.1E00.3333

You can verify the previous command by entering the show cluster members command in user EXEC mode on the command switch.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show cluster candidates

Displays a list of candidate switches.

show cluster members

Displays information about the cluster members.


cluster run

Use the cluster run global configuration command to enable clustering on a switch. Use the no form of this command to disable clustering on a switch.

cluster run

no cluster run

default cluster run

Syntax Description

no

Disable clustering on a switch.

default

Enable clustering on a switch.


Defaults

Clustering is enabled on all switches.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When you enter the no cluster run command on a command switch, the command switch is disabled.

When you enter the no cluster run command on a member switch, it is removed from the cluster.

When you enter the no cluster run command on a switch, it disables clustering on that switch. This switch is then incapable of becoming a candidate switch.

Examples

The following example shows how to disable clustering on the command switch:

Switch(config)# no cluster run

You can verify the previous command by entering the show cluster command in user EXEC mode.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster setup

Use the cluster setup privileged EXEC command on the command switch to automatically build a cluster.

cluster setup

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You can use the cluster setup command to add new switches to an existing cluster. The cluster setup command provides a high-level view of the configuration and guides you through the configuration change process. You can only see candidate switches that are one hop away from the command switch and have no IP address. To see devices farther away, use the show cluster members or show cluster candidates command.

If a candidate switch has a password, this information will not be passed to the cluster.

Examples

The following is an example of the cluster setup command output:

Switch# cluster setup

         --- Cluster Configuration Dialog ---
 
At any point you may enter a question mark '?' for help.
Use ctrl-c to abort configuration dialog at any prompt.
Default settings are in square brackets '[]'.

This switch is already configured as cluster command switch:
Command Switch Name:clus1, contains 1 members

Continue with cluster configuration dialog? [yes/no]:yes
The suggested Cluster configuration is as follows:

                                                |---Upstream---|
SN MAC Address    Name         PortIf FEC Hops   SN PortIf  FEC  State
0  0030.0002.0240 c2950-1                0                    Up   (Cmdr)
1* 0001.96e4.e580 c2950-2    Fa0/1       1     0  Fa0/9       Up  
2* 0001.96e4.e580 c2950-2    Fa0/3       1     0  Fa0/3       Up  
3* 0001.96e4.e580 c2950-2    Fa0/5       1     0  Fa0/5       Up  
4* 0050.2ae6.2e00 2900-1     Fa0/1       1     0  Fa0/1       Up  


The following configuration command script was created:
cluster member 1 mac-address 0001.96e4.e580
cluster member 2 mac-address 0001.96e4.e580
cluster member 3 mac-address 0001.96e4.e580
cluster member 4 mac-address 0050.2ae6.2e00
!
end

Use this configuration? [yes/no]:yes
 
Building configuration...
[OK]
Use the enabled mode 'configure' command to modify this configuration.
 
Switch#

Related Commands

Command
Description

cluster enable

Enables a switch as the cluster command switch, assigns a cluster name, and optionally assigns a member number to it.

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show cluster candidates

Displays a list of candidate switches.

show cluster members

Displays information about the cluster members.


cluster standby-group

Use the cluster standby-group global configuration command to enable command switch redundancy by binding the Hot Standby Router Protocol (HSRP) standby group to the cluster. Use the no form of this command to unbind the cluster from the HSRP standby group.

cluster standby-group HSRP-group-name

no cluster standby-group

default cluster standby-group

Syntax Description

HSRP-group-name

Name of the HSRP group that is bound to the cluster. The group name is limited to 32 characters.

no

Unbind the cluster from the HSRP standby group.

default

Unbind the cluster from the HSRP standby group.


Defaults

The cluster is not bound to any HSRP group.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You must enter this command only on the command switch. If you enter it on a member switch, an error message appears.

The command switch propagates the cluster-HSRP binding information to all members. Each member switch stores the binding information in its nonvolatile RAM (NVRAM).

The HSRP group name must be a valid standby group; otherwise, the command exits with an error.

Examples

The following example shows how to bind the HSRP group named my_hsrp to the cluster. This command is executed on the command switch.

Switch(config)# cluster standby-group my_hsrp

The following example shows the error message when this command is executed on a command switch and the specified HSRP standby group does not exist:

Switch(config)# cluster standby-group my_hsrp
%ERROR: Standby group `my_hsrp' doesn't exist

The following example shows the error message when this command is executed on a member switch.

Switch(config)# cluster standby-group my_hsrp
%ERROR: This command runs only on the command switch

You can verify the previous commands by entering the show cluster command in user EXEC mode.

Related Commands

Command
Description

standby ip

Enables HSRP on the interface.

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show standby

Displays standby group information.


cluster timer

Use the cluster timer global configuration command on the command switch to set the interval in seconds between heartbeat messages. Use the no form of this command to set the interval to the default value.

cluster timer interval-in-secs

no cluster timer

default cluster timer

Syntax Description

interval-in-secs

Interval in seconds between heartbeat messages. The range is from
1 to 300 seconds.

no

Set the interval to the default value (8 seconds).

default

Set the interval to the default value (8 seconds).


Defaults

The interval is 8 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command with the cluster holdtime global configuration command only on the command switch. The command switch propagates the values to all its cluster members.

The holdtime is typically set as a multiple of the heartbeat interval timer (cluster timer). For example, it takes (holdtime-in-secs divided by the interval-in-secs) number of heartbeat messages to be missed in a row to declare a switch down.

Examples

The following example shows how to change the heartbeat interval timer and the duration on the command switch.

Switch(config)# cluster timer 3
Switch(config)# cluster holdtime 30

You can verify the previous commands by entering the show cluster command in user EXEC mode.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


delete

Use the delete privileged EXEC command to delete a file from the file system.

delete {device:}filename

Syntax Description

device:

Device containing the file to be deleted. Valid devices include the switch Flash memory.

filename

Name of file.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

A colon (:) follows the device variable. Do not enter spaces after the colon.

Examples

The following example shows how to delete a file from the switch Flash memory:

Switch# delete flash:filename

Related Commands

Command
Description

copy tftp

Downloads a file from a TFTP server to a device.


duplex

Use the duplex interface configuration command to specify the duplex mode of operation for Fast Ethernet or Gigabit Ethernet ports. Use the no form of this command to return the port to its default value.

duplex {full | half | auto}

no duplex

Syntax Description

full

Port is in full-duplex mode.

half

Port is in half-duplex mode.

auto

Port automatically detects whether it should run in full- or half-duplex mode.


Defaults

The default is auto.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Certain ports can be configured to be either full duplex or half duplex. Applicability of this command depends on the device to which the switch is attached.

For Fast Ethernet ports, setting the port to auto has the same effect as specifying half if the attached device does not autonegotiate the duplex parameter.

If the speed is set to auto, the switch negotiates with the device at the other end of the link for the speed setting and then forces the speed setting to the negotiated value. The duplex setting remains as configured on each end of the link, which could result in a duplex setting mismatch.


Note The Gigabit Ethernet ports can operate in either half- or full-duplex mode when they are set to 10 or 100 Mbps, but when they are set to1000 Mbps, they can only operate in the full-duplex mode.


If both the speed and duplex are set to specific values, autonegotiation is disabled.


Note For guidelines on setting the switch speed and duplex parameters, see the Catalyst 2950 Desktop Switch Hardware Installation Guide.


Examples

The following example shows how to set port 1 (Fast Ethernet port) to full duplex:

Switch(config)# interface fastethernet2/1
Switch(config-if)# duplex full

The following example shows how to set port 1 (Gigabit Ethernet port) to full duplex:

Switch(config)# interface gigabitethernet2/1
Switch(config-if)# duplex full

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

speed

Specifies the speed of a Fast Ethernet port.


enable last-resort

Use the enable last-resort global configuration command to specify what happens if the Terminal Access Controller Access Control System (TACACS) and Extended TACACS servers used by the enable command do not respond. Use the no form of this command to restore the default.

enable last-resort {password | succeed}

no enable last-resort

Syntax Description

password

Provide access to enable mode with entry of the privileged command level password. A password must contain from 1 to 25 uppercase and lowercase alphanumeric characters.

succeed

Provide access to enable mode without further question.


Defaults

Authentication is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This secondary authentication is used only if the first attempt fails.


Note This command is not used with Terminal Access Controller Access Control System Plus (TACACS+), a Cisco proprietary protocol that instead uses the authentication, authorization, and accounting (AAA) suite of commands.


Examples

In the following example, if the TACACS servers do not respond to the enable command, you can enable access by entering the privileged-level password:

Switch(config)# enable last-resort <password>

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

enable

Accesses privileged EXEC mode.

show running-config

Displays the running configuration on the switch.


enable use-tacacs

Use the enable use-tacacs global configuration command to enable the use of Terminal Access Controller Access Control System (TACACS) to determine whether a user can access the privileged command level. Use the no form of this command to disable TACACS verification.

enable use-tacacs

no enable use-tacacs


Tips If you use the enable use-tacacs command, you must also use the tacacs-server authenticate enable command, or you will be locked out of the privileged command level.


Syntax Description

This command has no arguments or keywords.

Defaults

TACACS verification is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When you add this command to the configuration file, the enable privilege EXEC command prompts for a new username and password. This pair is then passed to the TACACS server for authentication. If you are using Extended TACACS, it also sends any existing UNIX user identification code to the server.


Note This command initializes TACACS. Use the tacacs server-extended command to initialize Extended TACACS or use the aaa new-model command to initialize authentication, authorization, and accounting (AAA) and Terminal Access Controller Access Control System Plus (TACACS+).


Examples

The following example sets TACACS verification on the privileged EXEC login sequence:

Switch(config)# enable use-tacacs
Switch(config)# tacacs-server authenticate enable

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

tacacs-server authenticate enable

Indicates whether users can perform an attempted action under TACACS and extended TACACS.


exit

Use the exit VLAN database command to implement the proposed new VLAN database, increment the database configuration number, propagate it throughout the administrative domain, and return to privileged EXEC mode.

exit

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The exit command implements all the configuration changes you made since you entered VLAN database mode and uses them for the running configuration. This command returns you to privileged EXEC mode.

Examples

The following example shows how to implement the proposed new VLAN database and exit to privileged EXEC mode:

Switch(vlan)# exit
Switch#

You can verify the previous command by entering the show vlan brief command in privileged EXEC mode.

Related Commands

Command
Description

abort

Abandons the proposed new VLAN database, exits VLAN database mode, and returns to privileged EXEC mode.

apply

Implements the proposed new VLAN database, increments the database configuration revision number, propagates it throughout the administrative domain, and remains in VLAN database mode.

reset

Abandons the proposed VLAN database and remains in VLAN database mode. Resets the proposed database to the currently implemented VLAN database on the switch.

show vlan

Displays the parameters for all configured VLANs in the administrative domain.

shutdown vlan

Shuts down (suspends) local traffic on the specified VLAN.

vlan database

Enters VLAN database mode from the command-line interface (CLI).


flowcontrol

Use the flowcontrol interface configuration command on Gigabit Ethernet ports to control traffic rates during congestion. Use the no form of this command to disable flow control on the port.

flowcontrol {asymmetric | symmetric}

no flowcontrol

Syntax Description

asymmetric

Enable the local port to perform flow control of the remote port. If the local port is congested, it can request the remote port to stop transmitting. When the congestion clears, the local port requests that the remote port begin transmitting.

symmetric

Enable the local port to perform flow control only if the remote port can also perform flow control of the local port. If the remote port cannot perform flow control, the local port also does not.


Defaults

The default is asymmetric.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Examples

The following example shows how to configure the local port to support any level of flow control by the remote port:

Switch(config-if)# flowcontrol 

The following example shows how to configure the local port to control the traffic flow from the remote port:

Switch(config-if)# flowcontrol asymmetric

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show interface [interface-id] flow-control

Displays flow-control information for the specified port.


interface

Use the interface global configuration command to configure an interface type, create a switch virtual interface to be used as the management VLAN interface, and to enter interface configuration mode.

interface type port | vlan number

no interface type port | vlan number

Syntax Description

type

Type of interface to be configured. Can be Fast Ethernet or Gigabit Ethernet.

port

Port ID.

vlan number

VLAN number from 1 to 1001 to be used as the management VLAN. Do not enter leading zeroes.


Defaults

The default management VLAN interface is VLAN 1.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When creating a management VLAN interface, a space between vlan and number is accepted.

Only one management VLAN interface can be active.

You cannot delete the management VLAN 1 interface.

Before bringing up a new management VLAN interface with the no shutdown command, you must issue the shutdown command to disable the old one.

You can use the management command to shut down the active management VLAN interface and to enable the newly created management VLAN interface.

You can configure the management VLAN interface on static-access and trunk ports.

Examples

The following example shows how to enable the switch to configure interface 2:

Switch(config)# interface fa0/2
Switch(config-if)#

The following example shows how to change the management VLAN from VLAN 1 to VLAN 3. This series of commands should only be executed from the console. If these commands are executed through a Telnet session, the shutdown command disconnects the session, and there is no way to use IP to access the system.

Switch# configure terminal
Switch(config)# interface vlan 3
Switch(config-subif)# ip address 172.20.128.176 255.255.255.0
Switch(config-subif)# exit
Switch(config-if)# exit
Switch(config)# interface vlan 1
Switch(config-subif)# shutdown
Switch(config-subif)# exit
Switch(config-if)# exit
Switch(config)# interface vlan 3
Switch(config-subif)# no shutdown
Switch(config-subif)# exit
Switch(config-if)# exit

The following example shows how to change the management VLAN from VLAN 1 to VLAN 3 through a Telnet session. In this situation, the management command shuts down VLAN 1 and brings up VLAN 3. The Telnet session must be re-established through the new management VLAN.

Switch# configure terminal
Switch(config)# interface vlan 3
Switch(config-subif)# ip address 172.20.128.176 255.255.255.0
Switch(config-subif)# management

The following example shows how to copy the IP address and network mask information from the current management VLAN to VLAN 3 and make VLAN 3 the new management VLAN:

Switch# configure terminal
Switch(config)# interface vlan 3
Switch(config-subif)# management

You can verify the previous commands by entering the show interface and show interface vlan number command in privilege EXEC mode.

Related Commands

Command
Description

management

Shuts down the current management VLAN interface and enables the new management VLAN interface.

show interface

Displays the administrative and operational status of a switching (nonrouting) port.

shutdown

Disables a port and shuts down the management VLAN.


ip address

Use the ip address interface configuration command to set an IP address for a switch. Use the no form of this command to remove an IP address or to disable IP processing.

ip address ip-address subnet-mask

no ip address ip-address subnet-mask

Syntax Description

ip-address

IP address.

subnet-mask

Mask for the associated IP subnet.


Defaults

No IP address is defined for the switch.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

A switch can have one IP address.

The IP address of the switch can be accessed only by nodes connected to ports that belong to the management VLAN. By default, the management VLAN is VLAN 1, but you can configure a different VLAN as the management VLAN.

If you remove the IP address through a Telnet session, your connection to the switch will be lost.

If your switch receives its IP address from a Bootstrap Protocol (BOOTP) or a Dynamic Host Configured Protocol (DHCP) server and you remove the switch IP address by using the no ip address command, IP processing is disabled, and the BOOTP or DHCP server cannot reassign the address.

Examples

The following example shows how to configure the IP address for the switch on a subnetted network:

Switch(config)# interface vlan 1
Switch(config-if)# ip address 172.20.128.2 255.255.255.0 

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

clear ip address

Deletes an IP address for a switch without disabling the IP processing.


ip igmp snooping

Use the ip igmp snooping global configuration command to globally enable Internet Group Management Protocol (IGMP) snooping. Use the no form of this command to disable IGMP snooping.

ip igmp snooping

no ip igmp snooping

Syntax Description

This command has no arguments or keywords.

Defaults

By default, IGMP snooping is globally enabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When IGMP snooping is globally enabled, it enables IGMP snooping on all the existing VLAN interfaces. When IGMP snooping is globally disabled, it disables IGMP snooping on all the existing VLAN interfaces.

The configuration is saved in nonvolatile RAM (NVRAM).

Examples

The following example shows how to globally enable IGMP snooping:

Switch(config)# ip igmp snooping

The following example shows how to globally disable IGMP snooping:

Switch(config)# no ip igmp snooping

You can verify the previous commands by entering the show ip igmp snooping command in the privileged EXEC mode.

Related Commands

Command
Description

ip igmp snooping vlan

Enables IGMP snooping an a VLAN interface.

ip igmp snooping vlan immediate-leave

Enables the IGMP Immediate-Leave processing.

ip igmp snooping vlan mrouter

Configures a Layer 2 port as a multicast router port.

ip igmp snooping vlan static

Configures a Layer 2 port as a member of a group.

show ip igmp snooping

Displays the IGMP snooping configuration.


ip igmp snooping vlan

Use the ip igmp snooping vlan global configuration command to enable Internet Group Management Protocol (IGMP) snooping on a specific VLAN. Use the no form of this command to disable IGMP snooping on a VLAN interface.

ip igmp snooping vlan vlan-id

no ip igmp snooping vlan vlan-id

Syntax Description

vlan_id

VLAN ID value. The range is from 1 to 1001.


Defaults

By default, IGMP snooping is enabled when each VLAN is created.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command automatically configures the VLAN if it is not already configured. This information is saved in nonvolatile RAM (NVRAM).

Examples

The following example shows how to enable IGMP snooping on VLAN 2:

Switch(config)# ip igmp snooping vlan 2

The following example shows how to disable IGMP snooping on VLAN 2:

Switch(config)# no ip igmp snooping vlan 2

You can verify the previous commands by entering the show ip igmp snooping vlan command in the privileged EXEC mode.

Related Commands

Command
Description

ip igmp snooping

Globally enables IGMP snooping. IGMP snooping must be globally enabled in order to be enabled on a VLAN.

ip igmp snooping vlan immediate-leave

Enables the IGMP Immediate-Leave processing.

ip igmp snooping vlan mrouter

Configures a Layer 2 port as a multicast router port.

ip igmp snooping vlan static

Configures a Layer 2 port as a member of a group.

show ip igmp snooping

Displays the snooping configuration.


ip igmp snooping vlan immediate-leave

Use the ip igmp snooping immediate-leave global configuration command to enable Internet Group Management Protocol (IGMP) Immediate-Leave processing on a VLAN interface. Use the no form of this command to disable Immediate-Leave processing on the VLAN interface.

ip igmp snooping vlan vlan-id immediate-leave

no ip igmp snooping vlan vlan-id immediate-leave

Syntax Description

vlan-id

VLAN ID value. The range is between 1 to 1001.


Defaults

By default, IGMP Immediate-Leave processing is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use the Immediate-Leave feature only when there is a only one IP multicast receiver present on every port in the VLAN. The Immediate Leave configuration is saved in nonvolatile RAM (NVRAM).

Immediate Leave is supported only with IGMP version 2 hosts.

Examples

The following example shows how to enable IGMP Immediate-Leave processing on VLAN 1:

Switch(config)# ip igmp snooping vlan 1 immediate-leave

The following example shows how to disable IGMP Immediate-Leave processing on VLAN 1:

Switch(config)# no ip igmp snooping vlan 1 immediate-leave

You can verify the previous commands by entering the show ip igmp snooping vlan command in the privileged EXEC mode.

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping.

ip igmp snooping vlan mrouter

Configures a Layer 2 port as a multicast router port.

ip igmp snooping vlan static

Configures a Layer 2 port as a member of a group.

show ip igmp snooping

Displays the snooping configuration.

show mac-address-table multicast

Displays the Layer 2 multicast entries for a VLAN.


ip igmp snooping vlan mrouter

Use the ip igmp snooping vlan mrouter global configuration command to add a multicast router port and to configure the multicast router learning method. Use the no form of this command to remove the configuration.

ip igmp snooping vlan vlan-id mrouter interface | { learn {cgmp | pim-dvmrp}}

no ip igmp snooping vlan vlan-id mrouter interface | { learn {cgmp | pim-dvmrp}}

Syntax Description

vlan-id

Specify the VLAN ID. The range is from 1 to 1001.

interface

Specify the Fast Ethernet port that is configured to a static router port.

learn

Specify the multicast router learning method.

cgmp

Specify the multicast router snooping CGMP packets.

pim-dvmrp

Specify the multicast router snooping PIM-DVMRP packets.


Defaults

The default is pim-dvmrp.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The CGMP learning method is useful for controlling traffic in Cisco router environments.

The configured learning method is saved in nonvolatile RAM (NVRAM).

Static connections to multicast routers are supported only on switch ports.

Examples

The following example shows how to configure Fast Ethernet interface 0/6 as a multicast router port:

Switch(config)# ip igmp snooping vlan 1 mrouter fa0/6

The following example shows how to specify the multicast router learning method as CGMP:

Switch(config)# no ip igmp snooping vlan 1 mrouter learn cgmp

You can verify the previous commands by entering the show ip igmp snooping mrouter command in the privileged EXEC mode.


Related Commands

Command
Description

ip igmp snooping

Globally enables IGMP snooping.

ip igmp snooping vlan

Enables Internet Group Management Protocol (IGMP) snooping on the VLAN interface.

ip igmp snooping vlan immediate-leave

Configures IGMP Immediate-Leave processing.

ip igmp snooping vlan static

Configures a Layer 2 port as a member of a group.

show ip igmp snooping mrouter

Displays the statically and dynamically learned multicast router ports.


ip igmp snooping vlan static

Use the ip igmp snooping vlan vlan-id static global configuration command to add a Layer 2 port as a member of a multicast group. Use the no form of this command to remove the configuration.

ip igmp snooping vlan vlan-id static mac-address interface

no ip igmp snooping vlan vlan-id static mac-address interface

Syntax Description

vlan-id

VLAN ID value. The range is 1 to 1001.

static

Keyword to define the static group address.

mac-address

Group MAC address.

interface

Keyword to specify the Fast Ethernet port that is configured to a static router port.


Defaults

None configured.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The command is used to statically configure the IP multicast group member ports.

The static ports and groups are saved in nonvolatile RAM (NVRAM).

Static connections to multicast routers are supported only on switch ports.

Examples

The following example shows how to statically configure a host on an interface:

Switch(config)# ip igmp snooping vlan 1 static 0100.5e02.0203 fa0/6
Configuring port FastEthernet 0/6 on group 0100.5e02.0203

You can verify the previous commands by entering the show mac-address-table multicast command in the privileged EXEC mode.

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping.

ip igmp snooping vlan

Enables IGMP snooping on the VLAN interface.

ip igmp snooping vlan immediate-leave

Configures IGMP Immediate-Leave processing.

ip igmp snooping vlan mrouter

Configures a Layer 2 port as a multicast router port.

show mac-address-table multicast

Displays the Layer 2 multicast entries for a VLAN.


login

Use the login line configuration command to enable password checking at login. Use the no form of this command to disable password checking and to allow connections without a password.

login [local | tacacs]

no login

Syntax Description

local

(Optional) Select local password checking. Authentication is based on the username specified with the username global configuration command.

tacacs

(Optional) Select the Terminal Access Controller Access Control System (TACACS)-style user ID and password-checking mechanism.


Defaults

No password is assigned, and you cannot access the switch through Telnet. Virtual terminals require a password. If you do not set a password for a virtual terminal, it responds to attempted connections by displaying an error message and closing the connection.

Command Modes

Line configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If you specify the login command without the local or tacacs option, authentication is based on the password specified with the line configuration password command.


Note This command cannot be used with authentication, authorization, and accounting (AAA) and TACACS+. Use the login authentication command instead.


Examples

The following example shows how to set the password letmein on virtual terminal line 4:

Switch(config-line)# line vty 4
Switch(config-line)# password letmein
Switch(config-line)# login

The following example shows how to enable the TACACS-style user ID and password-checking mechanism:

Switch(config-line)# line 0
Switch(config-line)# password <mypassword> 
Switch(config-line)# login tacacs

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

enable password

Sets a local password to control access to various privilege levels.

password

Specifies a password on a line.

show running-config

Displays the running configuration on the switch.

username

Establishes a username-based authentication system.


login authentication

Use the login authentication line configuration command to enable authentication, authorization, and accounting (AAA) for logins. Use the no form of this command to either disable Terminal Access Controller Access Control System Plus (TACACS+) authentication for logins or to return to the default.

login authentication {default | list-name}

no login {default | list-name}

Syntax Description

default

Use the default list created with the AAA authentication login command.

list-name

Use the indicated list created with the AAA authentication login command.


Defaults

Login authentication is disabled.

Command Modes

Line configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

To create a default list that is used if no list is specified in the login authentication command, use the default keyword followed by the methods you want used in default situations. The default method list is automatically applied to all interfaces.

Examples

The following example shows how to specify TACACS+ as the default method for user authentication during login:

Switch(config)# aaa new-model
Switch(config)# aaa authentication login default tacacs
Switch(config)# line vty 0 4
Switch(config-line)# login authentication default tacacs

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

enable password

Sets a local password to control access to various privilege levels.

password

Specifies a password on a line.

show running-config

Displays the running configuration on the switch.

username

Establishes a username-based authentication system.


mac-address-table aging-time

Use the mac-address-table aging-time global configuration command to set the length of time that a dynamic entry remains in the MAC address table after the entry is used or updated. Use the no form of this command to use the default aging-time interval. The aging time applies to all VLANs.

mac-address-table aging-time age

no mac-address-table aging-time

Syntax Description

age

Number from 10 to 1000000 (seconds).


Defaults

The default is 300 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If hosts do not transmit continuously, increase the aging time to record the dynamic entries for a longer time. This can reduce the possibility of flooding when the hosts transmit again.

Examples

The following example shows how to set the aging time to 200 seconds:

Switch(config)# mac-address-table aging-time 200

You can verify the previous command by entering the show mac-address-table command in privileged EXEC mode.

Related Commands

Command
Description

clear mac-address-table

Deletes entries from the MAC address table.

mac-address-table secure

Adds secure addresses to the MAC address table.

show mac-address-table

Displays the MAC address table.


mac-address-table secure

Use the mac-address-table secure global configuration command to add secure addresses to the MAC address table. Use the no form of this command to remove secure entries from the MAC address table.

mac-address-table secure hw-addr interface [vlan vlan-id]

no mac-address-table secure hw-addr [vlan vlan-id]

Syntax Description

hw-addr

MAC address that is added to the table.

interface

Port to which packets destined for hw-addr are forwarded.

vlan vlan-id

(Optional) The interface and vlan parameters together specify a destination to which packets destined for hw-addr are forwarded.

The vlan keyword is optional if the port is a static-access VLAN port. In this case, the VLAN assigned to the port is assumed to be that of the port associated with the MAC address. This keyword is required for trunk ports.

The vlan-id is the ID of the VLAN to which secure entries are added. Valid IDs are 1 to 1001; do not enter leading zeroes.


Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Secure addresses can be assigned only to one port at a time. Therefore, if a secure address table entry for the specified MAC address and VLAN already exists on another port, it is removed from that port and assigned to the specified one.

Examples

The following example shows how to add a secure MAC address to VLAN 6 of port fa1/1:

Switch(config)# mac-address-table secure 00c0.00a0.03fa fa1/1 vlan 6

You can verify this command by entering the show mac-address-table command in privileged EXEC mode.

Related Commands

Command
Description

clear mac-address-table

Deletes entries from the MAC address table.

mac-address-table aging-time

Sets the length of time that a dynamic entry remains in the MAC address table after the entry is used or updated.

mac-address-table static

Adds static addresses to the MAC address table.

show mac-address-table

Displays the MAC address table.


mac-address-table static

Use the mac-address-table static global configuration command to add static addresses to the MAC address table. Use the no form of this command to remove static entries from the MAC address table.

mac-address-table static mac_addr interface out-ports-lists vlan vlan-id

no mac-address-table static mac_addr interface out-ports-lists vlan vlan-id

Syntax Description

mac_addr

MAC address added to the address table.

interface

Keyword for the output port interfaces.

out-port-list

List of ports to which packets received on ports in a VLAN are forwarded. All ports in the list must belong to the same VLAN.

vlan vlan-id

The vlan-id is the ID of the VLAN to which static address entries are forwarded. Valid IDs are 1 to 1001; do not enter leading zeroes.


Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When a packet is received on any port in the VLAN, it is forwarded to all the ports specified by the out-ports-lists in the same VLAN.

Examples

The following example shows how to statically configure a host on an interface:

Switch(config)# mac-address-table static c2f3.220a.12f4 fa0/1 fa0/2 fa0/8 vlan 4

You can verify the previous command by entering the show mac-address-table command in privileged EXEC mode.

Related Commands

Command
Description

clear mac-address-table

Deletes entries from the MAC address table.

mac-address-table aging-time

Sets the length of time that a dynamic entry remains in the MAC address table after the entry is used or updated.

mac-address-table secure

Adds secure addresses to the MAC address table.

show mac-address-table

Displays the MAC address table.


management

Use the management interface configuration command to shut down the current management VLAN interface and to enable the new management VLAN interface. The management VLAN is used to manage a cluster of switches. To use it for cluster management, apply it to a switched virtual interface or the management interface. The default management VLAN is VLAN 1; however, the management VLAN can be changed to a new management interface by using a different VLAN (one with IDs from
1 to 1001). This command also copies the current management VLAN IP information to the new management VLAN interface if no new IP address or network mask is provided. It also copies the cluster standby group configuration to the new management VLAN.

management

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

No default management or no management command exists to return the management VLAN to its default state.

The management command is not written to the configuration file, and it is not displayed in the output of the show running-config command.

Before entering the management command, make sure the following conditions exist:

You must be able to move your network management station to a switch port assigned to the same VLAN as the new management VLAN.

The network management station must have network connectivity to all switches involved in the management VLAN change.

The switch must already have a port assigned to the same VLAN as the management VLAN.

Use the management command to change the management VLAN on a single switch. Use the global configuration command cluster management-vlan n on the command switch to change the management VLAN on the entire cluster.

Examples

The following example shows how to shut down the current management VLAN interface and start VLAN 2 as the management VLAN:

Switch# configure terminal
Switch(config)# interface vlan 2
Switch(config-subif)# ip address 172.20.128.176 255.255.255.0
Switch(config-subif)# management
Switch(config-subif)# exit
Switch(config)#

The following example shows how to copy the IP address and network mask from the current management VLAN to VLAN 2 and make VLAN 2 the management VLAN:

Switch# configure terminal
Switch(config)# interface vlan 2
Switch(config-subif)# management
Switch(config-subif)# exit
Switch(config)#

You can verify the previous command by entering the show interface vlan number command in privileged EXEC mode.

Related Commands

Command
Description

cluster management-vlan

Changes the management VLAN for the entire cluster.

interface vlan

Configures an interface type, creates a switch virtual interface to be used as the management VLAN interface, and enters interface configuration mode

show interface vlan number

Displays the administrative and operational status of a switching (nonrouting) port.


ntp access-group

Use the ntp access-group global configuration command to control access to the system Network Time Protocol (NTP) services. Use the no form of the command to remove access control to the system NTP services.

ntp access-group {query-only | serve-only | serve | peer} access-list-number

no ntp access-group {query-only | serve | peer}

Syntax Description

query-only

Enable only NTP control queries. See RFC 1305 (NTP version 3).

serve-only

Enable only time requests.

serve

Enable time requests and NTP control queries, but does not enable the system to synchronize to the remote system.

peer

Enable time requests and NTP control queries; enable the system to synchronize to the remote system.

access-list-number

Number (1 to 99) of a standard IP access list.


Defaults

NTP is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The access group options are scanned in the following order from least restrictive to most restrictive:

1. peer

2. serve

3. serve-only

4. query-only

Access is granted for the first match that is found. If no access groups are specified, all access is granted to all sources. If any access groups are specified, only the specified access is granted. This facility provides minimal security for the time services of the system. If tighter security is desired, use the NTP authentication facility.

Examples

The following example shows how to configure the system to be synchronized by a peer from access
list 99.

However, the system restricts access to allow time requests only from access list 42:

Switch(config)# ntp access-group peer 99
Switch(config)# ntp access-group serve-only 42

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

access-list

Differentiates one packet from another so that different treatment can be applied.

show running-config

Displays the running configuration on the switch.


ntp authenticate

Use the ntp authenticate global configuration command to enable Network Time Protocol (NTP) authentication. Use the no form of this command to disable the feature.

ntp authenticate

no ntp authenticate

Syntax Description

This command has no keywords or arguments.

Defaults

NTP authentication is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command if you want authentication. If this command is specified, the system will not synchronize to a system unless it carries one of the authentication keys specified in the ntp trusted-key command.

Examples

The following example shows how to enable NTP authentication:

Switch(config)# ntp authenticate

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp authentication-key

Defines an authentication key for NTP.

ntp trusted-key

Authenticates the identity of a system to which NTP will synchronize.

show running-config

Displays the running configuration on the switch.


ntp authentication-key

Use the ntp authentication-key global configuration command to define an authentication key for Network Time Protocol (NTP). Use the no form of this command to remove the authentication key for NTP.

ntp authentication-key number md5 value

no ntp authentication-key number

Syntax Description

number

Key number (1 to 4294967295).

md5

Use MD5 authentication.

value

Key value (an arbitrary string of up to eight characters, with the exception of control or escape characters).


Defaults

No authentication key is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command to define authentication keys for use with other NTP commands for greater security.

Examples

The following example shows how to set authentication key 10 to aNiceKey:

Switch(config)# ntp authentication-key 10 md5 aNiceKey

You can verify the previous command by entering the show running-config command in privileged EXEC mode.


Note When this command is written to nonvolatile RAM (NVRAM), the key is encrypted so that it is not displayed when the configuration is viewed.


Related Commands

Command
Description

ntp authenticate

Enables NTP authentication.

ntp peer

Configures the switch system clock to synchronize a peer or to be synchronized by a peer.

ntp server

Allows the switch system clock to be synchronized by a time server.

ntp trusted-key

Authenticates the identity of a system to which NTP will synchronize.

show running-config

Displays the running configuration on the switch.


ntp broadcast client

Use the ntp broadcast client interface configuration command to allow the system to receive Network Time Protocol (NTP) broadcast packets on an interface. Use the no form of the command to disable this capability.

ntp broadcast client

no ntp broadcast [client]

Syntax Description

This command has no arguments or keywords.

Defaults

Broadcast client mode is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command to allow the system to listen to broadcast packets on an interface-by-interface basis. You must configure this command on the management VLAN interface. By default, the management VLAN is VLAN 1, but you can configure a different VLAN as the management VLAN.

Examples

The following example shows how to synchronize the router to NTP packets that are broadcast on interface VLAN 1:

Switch(config-if)# interface vlan1
Switch(config-if)# ntp broadcast client

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp broadcastdelay

Sets the estimated round-trip delay between the IOS software and an NTP broadcast server.

show running-config

Displays the running configuration on the switch.


ntp broadcastdelay

Use the ntp broadcastdelay global configuration command to set the estimated round-trip delay between the IOS software and a Network Time Protocol (NTP) broadcast server. Use the no form of this command to revert to the default value.

ntp broadcastdelay microseconds

no ntp broadcastdelay

Syntax Description

microseconds

Estimated round-trip time (in microseconds) for NTP broadcasts. The range is from 1 to 999999.


Defaults

The default is 3000 microseconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command when the switch is configured as a broadcast client and the round-trip delay on the network is other than 3000 microseconds.

Examples

The following example shows how to configure the estimated round-trip delay between the switch and the broadcast client to 5000 microseconds:

Switch(config)# ntp broadcastdelay 5000

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp broadcast client

Allows the system to receive NTP broadcast packets on an interface.

show running-config

Displays the running configuration on the switch.


ntp broadcast destination

Use the ntp broadcast destination interface configuration command to configure a Network Time Protocol (NTP) server or peer to restrict the broadcast of NTP frames to the IP address of a designated client or a peer. Use the no form of the command to return the setting to its default.

ntp broadcast destination IP-address

no ntp broadcast destination

Syntax Description

IP-address

IP address or host name of a designated client or a peer.


Defaults

No IP address or host name is assigned.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You must configure this command on the management VLAN interface. By default, the management VLAN is VLAN 1, but you can configure a different VLAN as the management VLAN.

Related Commands

Command
Description

ntp broadcast client

Allows the system to receive NTP broadcast packets on an interface.

ntp broadcastdelay

Sets the estimated round-trip delay between the IOS software and an NTP broadcast server.


ntp broadcast key

Use the ntp broadcast key interface configuration command to configure a Network Time Protocol (NTP) server or peer to broadcast NTP frames with the authentication key embedded into the NTP packet. Use the no form of the command to return the setting to its default.

ntp broadcast key number

no ntp broadcast key

Syntax Description

number

The NTP authentication key that is embedded in the NTP packet.
The range is from 0 to 4294967295.


Defaults

No NTP broadcast key is defined.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You must configure this command on the management VLAN interface. By default, the management VLAN is VLAN 1, but you can configure a different VLAN as the management VLAN.

Related Commands

Command
Description

ntp broadcast client

Allows the system to receive NTP broadcast packets on an interface.

ntp broadcastdelay

Sets the estimated round-trip delay between the IOS software and an NTP broadcast server.


ntp broadcast version

Use the ntp broadcast interface configuration command to specify that a specific interface should send Network Time Protocol (NTP) broadcast packets. Use the no form of the command to disable this capability.

ntp broadcast version number

no ntp broadcast

Syntax Description

number

Number from 1 to 3.


Defaults

Version 3 is the default.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If you are using version 2 and the NTP synchronization does not occur, use NTP version 2.

You must configure this command on the management VLAN interface. By default, the management VLAN is VLAN 1, but you can configure a different VLAN as the management VLAN.

Examples

The following example shows how to configure interface VLAN 1 to send NTP version 2 packets:

Switch(config-if)# interface vlan1
Switch(config-if)# ntp broadcast version 2

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp broadcast client

Allows the system to receive NTP broadcast packets on an interface.

ntp broadcastdelay

Sets the estimated round-trip delay between the IOS software and an NTP broadcast server.

show running-config

Displays the running configuration on the switch.


ntp clock-period

Do not enter this command; it is documented for informational purposes only. The system automatically generates this command as the Network Time Protocol (NTP) determines the clock error and compensates.

As the NTP compensates for the error in the system clock, it keeps track of the correction factor for this error. The system automatically saves this value into the system configuration using the ntp clock-period global configuration command. The system uses the no form of this command to revert to the default.

ntp clock-period value

no ntp clock-period

Syntax Description

value

Amount to add to the system clock for each clock hardware tick (in units of 2 to 32 seconds).


Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If a write memory command is entered to save the configuration to nonvolatile RAM (NVRAM), this command is automatically added to the configuration. It is a good idea to perform this task after NTP has been running for a week or so; NTP synchronizes more quickly if the system is restarted.

ntp disable

Use the ntp disable interface configuration command to prevent an interface from receiving Network Time Protocol (NTP) packets. To enable receipt of NTP packets on an interface, use the no form of the command.

ntp disable

no ntp disable

Syntax Description

This command has no arguments or keywords.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You must configure this command on the management VLAN interface. By default, the management VLAN is VLAN 1, but you can configure a different VLAN as the management VLAN.

The preferred command to disable NTP is no ntp.

Examples

The following example shows how to prevent interface VLAN 1 from receiving NTP packets:

Switch(config-if)# interface vlan1
Switch(config-if)# ntp disable

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.


ntp max-associations

Use the ntp max-associations global configuration command to set the maximum number of Network Time Protocol (NTP) associations that are allowed on a server. Use the no form of this command to disable this feature.

ntp max-associations [number]

no ntp max-associations

Syntax Description

number

(Optional) Specify the number of NTP associations. The range is from
0 to 4294967295.


Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command provides a simple method to control the number of peers that can use the switch to synchronize to it through NTP.

After you enable a switch as an NTP server, use this command to set the maximum number of associations that are allowed on a server.

Examples

The following example shows how to set the maximum number of NTP associations to 44:

Switch(config)# ntp max-associations 44

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.


ntp peer

Use the ntp peer global configuration command to configure the switch system clock to synchronize a peer or to be synchronized by a peer. Use the no form of the command to disable this capability.

ntp peer ip-address [version number] [key keyid] [source interface] [prefer]

no ntp peer ip-address

Syntax Description

ip-address

IP address of the peer providing, or being provided, the clock synchronization.

version number

(Optional) Define the Network Time Protocol (NTP) version number as version 1, 2, or 3.

key keyid

(Optional) Define the authentication key, which is used when sending packets to this peer. The range is from 0 to 4294967295.

source interface

(Optional) Authentication key to use when sending packets to this peer. Also includes the name of the interface from which to pick the IP source address.

prefer

(Optional) Make this peer the preferred peer that provides synchronization.


Defaults

No IP address is defined.

NTP version 3 is the default.

No NTP authentication key is defined.

No source interface is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Using the prefer keyword will reduce switching between peers.

If you are using the default NTP version of 3 and NTP synchronization does not occur, try using NTP version 2. Many NTP servers on the Internet run version 2.

Examples

The following example shows how to configure the router to allow its system clock to be synchronized with the clock of the peer (or vice versa) at IP address 131.108.22.33 using NTP version 2. The source IP address will be the address of Ethernet 0.

Switch(config)# ntp peer 131.108.22.33 version 2 source Ethernet 0

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp authentication-key

Defines an authentication key for NTP.

ntp server

Allows the switch system clock to be synchronized by a time server.

ntp source

Uses a particular source address in NTP packets.

show running-config

Displays the running configuration on the switch.


ntp server

Use the ntp server global configuration command to allow the switch system clock to be synchronized by a time server. Use the no form of the command to disable this capability.

ntp server ip-address [version number] [key keyid] [source interface] [prefer]

no ntp server ip-address

Syntax Description

ip-address

IP address of the time server providing the clock synchronization.

version number

(Optional) Define the Network Time Protocol (NTP) version number (1 to 3).

key keyid

(Optional) Define the authentication key. Authentication key to use when sending packets to this peer. The range is from 0 to 4294967295.

source interface

(Optional) Identify the interface from which to pick the IP source address.

prefer

(Optional) Make this server the preferred server that provides synchronization.


Defaults

No IP address is defined.

NTP version 3 is the default.

No NTP authentication key is defined.

No source interface is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command if you want to allow this machine to synchronize with the specified server. The server will not synchronize to this machine.

Using the prefer keyword will reduce switching between servers.

If you are using the default NTP version of 3 and NTP synchronization does not occur, try using NTP version 2. Many NTP servers on the Internet run version 2.

Examples

The following example shows how to configure the router to allow its system clock to be synchronized with the clock of the peer at IP address 128.108.22.44 using NTP version 2:

Switch(config)# ntp server 128.108.22.44 version 2

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp authentication-key

Defines an authentication key for NTP.

ntp server

Allows the switch system clock to be synchronized by a time server.

ntp source

Uses a particular source address in NTP packets.

show running-config

Displays the running configuration on the switch.


ntp source

Use the ntp source global configuration command to use a particular source address in Network Time Protocol (NTP) packets. Use the no form of this command to remove the specified source address.

ntp source interface

no ntp source

Syntax Description

interface

Any valid system interface name.


Defaults

No source address is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command when you want to use a particular source IP address for all NTP packets. The address is taken from the specified interface. This command is useful if the address on an interface cannot be used as the destination for reply packets. If the source keyword is present on an ntp server or ntp peer command, that value overrides the global value.

Examples

The following example shows how to configure the router to use the IP address of VLAN 1 as the source address of all outgoing NTP packets:

Switch(config)# ntp source vlan1

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp peer

Configures the switch system clock to synchronize a peer or to be synchronized by a peer.

ntp server

Allows the switch system clock to be synchronized by a time server.

show running-config

Displays the running configuration on the switch.


ntp trusted-key

Use the ntp trusted-key global configuration command if you want to authenticate the identity of a system to which the Network Time Protocol (NTP) will synchronize. Use the no form of this command to disable authentication of the identity of the system.

ntp trusted-key key-number

no ntp trusted-key key-number

Syntax Description

key-number

Authentication key to be used for time authentication. The range is from
1 to 4294967295.


Defaults

No key number is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If authentication is enabled, use this command to define one or more key numbers that a peer NTP system must provide in its NTP packets in order for this system to synchronize to it. The key numbers must correspond to the keys defined with the ntp authentication-key command. This provides protection against accidentally synchronizing the system to a system that is not allowed because the other system must know the correct authentication key.

Examples

The following example shows how to configure the system to synchronize only to systems providing authentication key 42 in its NTP packets:

Switch(config)# ntp authenticate
Switch(config)# ntp authentication-key 42 md5 aNiceKey
Switch(config)# ntp trusted-key 42

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ntp authenticate

Enables NTP authentication.

ntp authentication-key

Defines an authentication key for NTP.

show running-config

Displays the running configuration on the switch.


port group

Use the port group interface configuration command to assign a port to a Fast EtherChannel or Gigabit EtherChannel port group. Up to six port groups can be created on a switch. Up to eight ports can belong to a source-based or destination-based port group. Use the no form of this command to remove a port from a port group.

port group group-number [distribution {source | destination}]

no port group

Syntax Description

group-number

Port group number to which the port belongs. The range is
from 1 to 6.

distribution {source | destination}

(Optional) Forwarding method for the port group.

source—Set the port to forward traffic to a port group based on the packet source address. This is the default forwarding method

destination—Set the port to forward traffic to a port group based on the packet destination address.


Defaults

Port does not belong to a port group.

The default forwarding method is source.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The following restrictions apply for all ports:

Do not group Fast Ethernet and gigabit ports together.

No port group member can be configured for Switched Port Analyzer (SPAN) port monitoring.

No port group member can be enabled for port security.

You can create up to six port groups of all source-based, all destination-based, or a combination of source-based and destination-based port groups. A source-based port group can have up to eight ports in its group. A destination-based port group can also have only eight ports in its group. You cannot mix source-based and destination-based ports in the same group.

Port group members must belong to the same set of VLANs and must be all static-access or all trunk ports.

When a group is first formed, the switch automatically sets the following parameters to be the same on all ports:

VLAN membership of ports in the group

VLAN mode (static or trunk) of ports in the group

Encapsulation method of the trunk

Native VLAN configuration if the trunk uses IEEE 802.1Q

Allowed VLAN list configuration of the trunk port

Spanning Tree Protocol (STP) Port Fast option

STP port priority

STP path cost

Protected port

Configuration of the first port added to the group is used when setting the above parameters for other ports in the group. After a group is formed, changing any parameter in the above list changes the parameter on all other ports.

Use the distribution keyword to customize the port group to your particular environment. The forwarding method you choose depends on how your network is configured. However, source-based forwarding works best for most network configurations.

Examples

The following example shows how to add a port to a port group by using the default source-based forwarding:

Switch(config-if)# port group 1

The following example shows how to add a port to a group by using destination-based forwarding:

Switch(config-if)# port group 2 distribution destination

You can verify the previous commands by entering the show port group command in privileged EXEC mode.

Related Commands

Command
Description

show port group

Displays the ports that belong to a port group.


port monitor

Use the port monitor interface configuration command to enable Switch Port Analyzer (SPAN) port monitoring on a port. Use the no form of this command to return the port to its default value.

port monitor [interface | vlan vlan-id]

no port monitor [interface | vlan vlan-id]

Syntax Description

interface

(Optional) Port number for the SPAN to be enabled. The interface specified is the port to be monitored.

vlan vlan-id

(Optional) ID of the VLAN to be monitored.


Note VLAN 1 is the only valid option.



Defaults

Port does not monitor any other ports.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Enabling port monitoring without specifying a port causes all other ports in the same VLAN to be monitored.

Entering the port monitor vlan 1 command causes monitoring of all traffic to and from the IP address configured on VLAN 1.

The following restrictions apply for ports that have port-monitoring capability:

A monitor port cannot be in a Fast EtherChannel or Gigabit EtherChannel port group.

A monitor port cannot be enabled for port security.

A monitor port must be a member of the same VLAN as the port monitored. VLAN membership changes are not allowed on monitor ports and ports being monitored.

A monitor port cannot be a dynamic-access port or a trunk port. However, a static-access port can monitor a VLAN on a trunk or a dynamic-access port. The VLAN monitored is the one associated with the static-access port.

Port monitoring does not work if both the monitor and monitored ports are protected ports.

Examples

The following example shows how to enable port monitoring on port fa0/2:

Switch(config-if)# port monitor fa0/2

You can verify the previous command by entering the show port monitor command in privileged EXEC mode.

Related Commands

Command
Description

show port monitor

Displays the ports for which SPAN port monitoring is enabled.


port protected

Use the port protected interface configuration command to isolate unicast, multicast, and broadcast traffic at Layer 2 from other protected ports on the same switch. Use the no form of the command to disable the protected port.

port protected

no port protected

Syntax Description

This command has no keywords or arguments.

Defaults

No protected port is defined.

A monitor port can not be configured as a protected port. However, it is possible to monitor or a protected port.

A protected port continues to forward unicast, multicast, and broadcast traffic to unprotected ports and vice versa.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The port protection feature is local to the switch; communication between protected ports on the same switch is possible only through a Layer 3 device. To prevent communication between protected ports on different switches, you must configure the protected ports for unique VLANs on each switch and configure a trunk link between the switches.

Port monitoring does not work if both the monitor and the monitored ports are protected ports. A monitor port cannot be configured as a protected port. However, you can monitor a protected port by a non protected port.

A protected port is different from a secure port.

Examples

The following example shows how to enable a protected port on interface fa0/3:

Switch(config)# interface fa0/3
Switch(config-if)# port protected

You can verify the previous command by entering the show port protected command in privileged EXEC mode.

Related Commands

Command
Description

show port protected

Displays the ports that are in port-protected mode.


port security

Use the port security interface configuration command to enable port security on a port and restrict the use of the port to a user-defined group of stations. Use the no form of this command to return the port to its default value.

port security [action {shutdown | trap} | max-mac-count addresses]

no port security

Syntax Description

action {shutdown | trap}

(Optional) Action to take when an address violation occurs on this port.

shutdown—Disable the port when a security violation occurs.

trap—Generate an SNMP trap when a security violation occurs

max-mac-count addresses

(Optional) The maximum number of secure addresses that this port can support. The range is from 1 to 132.


Defaults

Port security is disabled.

When enabled, the default action is to generate an SNMP trap.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If you specify trap, use the snmp-server host command to configure the SNMP trap host to receive traps.

The following restrictions apply to secure ports:

A secure port cannot belong to a Fast EtherChannel or Gigabit EtherChannel port group.

A secure port cannot have Switched Port Analyzer (SPAN) port monitoring enabled on it.

A secure port cannot be a dynamic-access port or a trunk port.

Examples

The following example shows how to enable port security and what action the port takes in case of an address violation (shutdown).

Switch(config-if)# port security action shutdown

The following example shows how to set the maximum number of addresses that the port can learn to 8.

Switch(config-if)# port security max-mac-count 8

You can verify the previous commands by entering the show port security command in privileged EXEC mode.

Related Commands

Command
Description

show port security

Displays the port security settings defined for the port.


port storm-control

Use the port storm-control interface configuration command to enable broadcast, multicast, or unicast storm control on a port. Use the no form of this command to disable storm control or one of the storm-control parameters on the port.

port storm-control {broadcast | multicast | unicast} {{action {filter | shutdown} | threshold {rising rising-number falling falling-number} | trap}}

no port storm-control {broadcast | multicast | unicast}

Syntax Description

{broadcast | multicast | unicast}

Determine the type of packet-storm suppression.

broadcast—Enable broadcast storm control on the port.

multicast—Enable multicast storm control on the port.

unicast—Enable unicast storm control on the port.

{action {filter | shutdown}

(Optional) Determines the type of action to perform.

filter—Filter traffic during a storm.

shutdown—Disable the port during a storm.

threshold {rising rising-number falling falling-number}

Defines the rising and falling thresholds

rising rising-number—Block the flooding of storm packets when the value specified for rising-number is reached. The rising-number is 0 to 4294967295 packets per second.

falling falling-number—Restart the normal transmission of broadcast packets when the value specified for falling-number is reached. The falling-number is 0 to 4294967295 packets per second.

trap

(Optional) Generate an SNMP trap when the traffic on the port crosses the rising or falling threshold. Traps are generated only for broadcast traffic and not for unicast or multicast traffic.


Defaults

Broadcast, multicast, and unicast storm control are disabled.

The rising thresholds are 500 broadcast packets per second, 2500 multicast packets per second, and 5000 unicast packets per second.

The falling thresholds are 250 broadcast packets per second, 1200 multicast packets per second, and 2500 unicast packets per second.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Do not set the rising and falling thresholds to the same value.

Examples

The following example shows how to enable broadcast storm control on a port. In this example, transmission is inhibited when the number of broadcast packets arriving on the port reaches 1000 and is restarted when the number drops to 200.

Switch(config-if)# port storm-control broadcast threshold rising 1000 falling 200

You can verify the previous command by entering the show port storm-control command in privileged EXEC mode.

Related Commands

Command
Description

show port storm-control

Displays the packet-storm control information.


rcommand

Use the rcommand user EXEC command to start a Telnet session and to execute commands on a member switch from the command switch. To end the session, enter the exit command.

rcommand {n | commander | mac-address hw-addr}

Syntax Description

n

Provide the number that identifies a cluster member. The range is from 0 to 15.

commander

Provide access to the command switch from a member switch.

mac-address hw-addr

MAC address of the member switch.


Command Modes

User EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the switch is the command switch but the member switch n does not exist, an error message appears. To obtain the switch number, enter the EXEC mode show cluster members command on the command switch.

You can use this command to access a member switch from the command-switch prompt or to access a command switch from the member-switch prompt.

For 2950 switches, the Telnet session accesses the member-switch command-line interface (CLI) at the same privilege level as on the command switch. For example, if you execute this command at user level on the cluster command switch, the member switch is accessed at user level. If you use this command on the command switch at privileged level, the command accesses the remote device at privileged level. If you use an intermediate enable-level lower than privileged, access to the member switch is at user level.

Examples

The following example shows how to start a session with member 3. All subsequent commands are directed to member 3 until you enter the exit command or close the session.

Switch# rcommand 3
Switch-3# show version
Cisco Internet Operating System Software ...
...
Switch-3# exit
Switch#

Related Commands

Command
Description

show cluster members

Displays information about the cluster members.


reset

Use the reset VLAN database command to abandon the proposed VLAN database and remain in VLAN database mode. This command resets the proposed database to the currently implemented VLAN database on the switch.

reset

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Examples

The following example shows how to abandon the proposed VLAN database and reset to the current VLAN database:

Switch(vlan)# reset
Switch(vlan)#

You can verify the previous command by entering the show changes and show proposed commands in VLAN database mode.

Related Commands

Command
Description

abort

Abandons the proposed new VLAN database, exits VLAN database mode, and returns to privileged EXEC mode.

apply

Implements the proposed new VLAN database, increments the database configuration revision number, propagates it throughout the administrative domain, and remains in VLAN database mode.

exit

Implements the proposed new VLAN database, increments the database configuration number, propagates it throughout the administrative domain, and returns to privileged EXEC mode.

show changes

Displays the differences between the VLAN database currently on the switch and the proposed VLAN database.

show proposed

Displays the proposed VLAN database or a selected VLAN from it.

shutdown vlan

Shuts down (suspends) local traffic on the specified VLAN.

vlan database

Enters VLAN database mode from the command-line interface (CLI).


rmon collection stats

Use the rmon collection stats interface configuration command to collect Ethernet group statistics. The Ethernet group statistics include utilization statistics about broadcast and multicast packets, and error statistics about Cyclic Redundancy Check (CRC) alignment errors and collisions. Use the no form of this command to return to the default setting.

rmon collection stats index [owner name]

no rmon collection stats index [owner name]

Syntax Description

index

Remote Network Monitoring (RMON) collection control index. The range is 1 to 65535.

owner name

(Optional) Owner of the RMON collection.


Defaults

The RMON statistics collection is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The RMON statistics collection command is based on hardware counters.

Examples

The following example shows how to collect rmon statistics for the owner root on interface fa0/1:

Switch(config)# interface fa0/1
Switch(config-if)# rmon collection stats 2 owner root

You can verify this command by entering the show rmon statistics command in user EXEC mode.

Related Commands

Command
Description

show rmon statistics

Displays RMON statistics.

For more information on this command, refer to the complete IOS Release 12.0 documentation set available on Cisco.com.


show changes

Use the show changes VLAN database command to display the differences between the VLAN database currently on the switch and the proposed VLAN database. You can also display the differences between the two for a selected VLAN.

show changes [vlan-id] | [{begin | exclude | include} expression]

Syntax Description

vlan-id

(Optional) ID of the VLAN in the current or proposed database. If this variable is omitted, all the differences between the two VLAN databases are displayed, including the pruning state and Version 2 mode. Valid IDs are from 1 to 1001; do not enter leading zeroes.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show changes command. It displays the differences between the current and proposed databases.

Switch(vlan)# show changes
ADDED:
    Name:VLAN0003
    Media Type:Ethernet
    VLAN 802.10 Id:100003
    State:Operational
    MTU:1500

ADDED:
    Name:VLAN0004
    Media Type:Ethernet
    VLAN 802.10 Id:100004
    State:Operational
    MTU:1500

The following is sample output from the show changes 4 command. It displays the differences between VLAN 4 in the current database and the proposed database.

Switch(vlan)# show changes 4

ADDED:
    Name:VLAN0004
    Media Type:Ethernet
    VLAN 802.10 Id:100004
    State:Operational

Related Commands MTU:1500

Command
Description

show current

Displays the current VLAN database on the switch or a selected VLAN.

show proposed

Displays the proposed VLAN database or a selected VLAN.


show cluster

Use the show cluster user EXEC command to display the cluster status and a summary of the cluster to which the switch belongs. This command can be entered on command and member switches.

show cluster | [{begin | exclude | include} expression]

Syntax Descriptionshow cluster

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

User EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the switch is not a command switch or a member switch, the command displays an empty line at the prompt.

On a member switch, this command displays the identity of the command switch, the switch member number, and the state of its connectivity with the command switch.

On a command switch, this command displays the cluster name, and the total number of members. It also shows the cluster status and time since the status changed. If redundancy is enabled, it displays the primary and secondary command-switch information.

If you enter this command on a switch that is not a cluster member, the error message Not a management cluster member is displayed.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output when this command is executed on the active command switch:

Switch# show cluster
Command switch for cluster "Ajang"
        Total number of members:        7
        Status:                         1 members are unreachable
        Time since last status change:  0 days, 0 hours, 2 minutes
        Redundancy:                     Enabled
                Standby command switch: Member 1
                Standby Group:          Ajang_standby
                Standby Group Number:   110
        Heartbeat interval:             8
        Heartbeat hold-time:            80
        Extended discovery hop count:   3 

The following is sample output when this command is executed on a member switch:

Switch1# show cluster
Member switch for cluster "commander"
        Member number:                  3
        Management IP address:          192.192.192.192
        Command switch mac address:     0000.0c07.ac14
        Heartbeat interval:             8
        Heartbeat hold-time:            80 

The following is sample output when this command is executed on a member switch that is configured as the standby command switch:

Switch# show cluster
Member switch for cluster "commander"
        Member number:                  3 (Standby command switch)
        Management IP address:          192.192.192.192
        Command switch mac address:     0000.0c07.ac14
        Heartbeat interval:             8
        Heartbeat hold-time:            80 

The following is sample output when this command is executed on the command switch that is separated from member 1:

Switch> show cluster
Command switch for cluster "Ajang"
        Total number of members:        7
        Status:                         1 members are unreachable
        Time since last status change:  0 days, 0 hours, 5 minutes
        Redundancy:                     Disabled
        Heartbeat interval:             8
        Heartbeat hold-time:            80
        Extended discovery hop count:   3 

The following is sample output when this command is executed on a member switch that is separated from the command switch:

Switch> show cluster
Member switch for cluster "commander"
        Member number:                  <UNKNOWN>
        Management IP address:          192.192.192.192
        Command switch mac address:     0000.0c07.ac14
        Heartbeat interval:             8
        Heartbeat hold-time:            80 

Related Commands

Command
Description

cluster enable

Enables a command-capable switch as the cluster command switch, assigns a cluster name, and optionally assigns a member number to it.

show cluster candidates

Displays a list of candidate switches.

show cluster members

Displays information about the cluster members.


show cluster candidates

Use the show cluster candidates user EXEC command on the command switch to display a list of candidate switches.

show cluster candidates [mac-address H.H.H. | detail] | [{begin | exclude | include} expression]

Syntax Description

mac-address H.H.H.

(Optional) Hexadecimal MAC address of the cluster candidate.

detail

(Optional) Display detailed information for all candidates.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

User EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You should enter this command only on a command switch.

If the switch is not a command switch, the command displays an empty line at the prompt.

The SN in the display means "switch member number." If E is displayed in the SN column, it means that the switch is discovered through extended discovery. The hop count is the number of devices the candidate is from the command switch.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show cluster candidates command.

Switch# show cluster candidates
                                                             |---Upstream---|
MAC Address    Name         Device Type      PortIf  FEC Hops SN PortIf  FEC
00d0.7961.c4c0 c2950-012    WS-C2950-12      Fa0/5        1   0  Fa0/3 
00d0.bbf5.e900 ldf-dist-128 WS-C3524-XL      Fa0/7        1   0  Fa0/24      
00e0.1e7e.be80 1900_Switch  1900             3        0   1   0  Fa0/11      
00e0.1e9f.7a00 c2924XL-24   WS-C2924-XL      Fa0/5        1   0  Fa0/3       
00e0.1e9f.8c00 c2912XL-12-2 WS-C2912-XL      Fa0/4        1   0  Fa0/7       
00e0.1e9f.8c40 c2912XL-12-1 WS-C2912-XL      Fa0/1        1   0  Fa0/9       
0050.2e4a.9fb0 C3508XL-0032 	WS-C3508-XL 	E
0050.354e.7cd0 C2924XL-0034 	WS-C2924-XL 	E

The following is sample output from the show cluster candidates command that uses the MAC address of a member switch directly connected to the command switch:

Switch# show cluster candidates mac-address 00d0.7961.c4c0
Device 'c2950-12' with mac address number 00d0.7961.c4c0
        Device type:            cisco WS-C2950-12
        Upstream MAC address:   00d0.796d.2f00 (Cluster Member 0)
        Local port:             Fa0/3   FEC number: 
        Upstream port:          Fa0/13  FEC Number: 
        Hops from cluster edge: 1
        Hops from command device: 1

The following is sample output from the show cluster candidates command that uses the MAC address of a member switch three hops from the cluster edge:

Switch# show cluster candidates mac-address 0010.7bb6.1cc0
Device 'c2950-24' with mac address number 0010.7bb6.1cc0
        Device type:            cisco WS-C2950-24
        Upstream MAC address:   0010.7bb6.1cd4
        Local port:             Fa2/1   FEC number: 
        Upstream port:          Fa0/24  FEC Number: 
        Hops from cluster edge: 3
        Hops from command device: -

The following is sample output from the show cluster candidates detail command:

Switch# show cluster candidates detail
Device 'c2950-12' with mac address number 00d0.7961.c4c0
        Device type:            cisco WS-C2950-12
        Upstream MAC address:   00d0.796d.2f00 (Cluster Member 1)
        Local port:             Fa0/3   FEC number: 
        Upstream port:          Fa0/13  FEC Number: 
        Hops from cluster edge: 1
        Hops from command device: 2
	Device '1900_Switch' with mac address number 00e0.1e7e.be80
        Device type:            cisco 1900
        Upstream MAC address:   00d0.796d.2f00 (Cluster Member 2)
        Local port:             3       FEC number: 0
        Upstream port:          Fa0/11  FEC Number: 
        Hops from cluster edge: 1
        Hops from command device: 2
Device 'c2924-XL' with mac address number 00e0.1e9f.7a00
        Device type:            cisco WS-C2924-XL
        Upstream MAC address:   00d0.796d.2f00 (Cluster Member 3)
        Local port:             Fa0/5   FEC number: 
        Upstream port:          Fa0/3   FEC Number: 
        Hops from cluster edge: 1
        Hops from command device: 2

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show cluster members

Displays information about the cluster members.


show cluster members

Use the show cluster members user EXEC command on the command switch to display information about the cluster members.

show cluster members [n | detail] | [{begin | exclude | include} expression]

Syntax Description

n

(Optional) Number that identifies a cluster member. The range is from 0 to 15.

detail

(Optional) Display detailed information for all cluster members.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

User EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You should enter this command only on a command switch.

If the cluster has no members, this command displays an empty line at the prompt.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show cluster members command. The SN in the display means switch number.

Switch# show cluster members
|---Upstream---|
SN MAC Address    Name         PortIf FEC Hops   SN PortIf  FEC  State
0  0030.0002.0240 c2950-001                0                    Up   (Cmdr)
4  0050.2ae6.2e00 2900XL-1     Fa0/1       1     0  Fa0/1       Up 

The following is sample output from the show cluster members for cluster member 4:

Switch# show cluster members 4
Device '2900XL-1' with member number 4
        Device type:           cisco WS-C2924M-XL
        MAC address:           0050.2ae6.2e00
        Upstream MAC address:  0030.0002.0240 (Cluster member 0)
        Local port:            Fa0/1   FEC number:
        Upstream port:         Fa0/1   FEC Number:
        Hops from command device:1

The following is sample output from the show cluster members detail command:

Switch# show cluster members detail
Device 'c2950-001' with member number 0 (Command Switch)
        Device type:           cisco WS-C2950-24
        MAC address:           0030.0002.0240
        Upstream MAC address:
        Local port:                    FEC number:
        Upstream port:                 FEC Number:
        Hops from command device:0
Device '2900XL-1' with member number 4
        Device type:           cisco WS-C2924M-XL
        MAC address:           0050.2ae6.2e00
        Upstream MAC address:  0030.0002.0240 (Cluster member 0)
        Local port:            Fa0/1   FEC number:
        Upstream port:         Fa0/1   FEC Number:
        Hops from command device:1

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show cluster candidates

Displays a list of candidate switches.


show current

Use the show current VLAN database command to display the current VLAN database on the switch or a selected VLAN from it.

show current [vlan-id] | [{begin | exclude | include} expression]

Syntax Description

vlan-id

(Optional) ID of the VLAN in the current database. If this variable is omitted, the entire VLAN database displays, included the pruning state and Version 2 mode.
Valid IDs are from 1 to 1001; do not enter leading zeroes.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show current command. It displays the current VLAN database.

Switch(vlan)# show current
    Name: default
    Media Type: Ethernet
    VLAN 802.10 Id: 100001
    State: Operational
    MTU: 1500
    Translational Bridged VLAN: 1002
    Translational Bridged VLAN: 1003

    Name: fddi-default
    Media Type: FDDI
    VLAN 802.10 Id: 101002
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Translational Bridged VLAN: 1
    Translational Bridged VLAN: 1003

    Name: token-ring-default
    Media Type: Token Ring
    VLAN 802.10 Id: 101003
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Ring Number: 0 
    Bridge Number: 1
    Parent VLAN: 1005
    Maximum ARE Hop Count: 7
    Maximum STE Hop Count: 7
    Backup CRF Mode: Disabled
    Translational Bridged VLAN: 1
    Translational Bridged VLAN: 1002

    Name: fddinet-default
    Media Type: FDDI Net
    VLAN 802.10 Id: 101004
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Bridge Number: 1
    STP Type: IBM

    Name: trnet-default
    Media Type: Token Ring Net
    VLAN 802.10 Id: 101005
    State: Operational
    MTU: 1500
    Bridge Type: SRB 
    Bridge Type: SRB
    Bridge Number: 1
    STP Type: IBM 

Related Commands STP Type: IBM

Command
Description

show changes

Displays the differences between the VLAN database currently on the switch and the proposed VLAN database.

show proposed

Displays the proposed VLAN database or a selected VLAN.


show env

Use the show env privileged EXEC command to display fan information for the Catalyst 2950 switch.

show env {all | fan} | [{begin | exclude | include} expression]

Syntax Description

all

Display both fan and temperature environmental status.

fan

Display the switch fan status.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show env all command:

Switch# show env all
FAN 1 is OK

The following is sample output from the show env fans command:

FAN 1 is OK

or

FAN 1 is FAULTY

show file systems

Use the show file systems privileged EXEC command to display file system information.

show file systems | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show file systems command:

Switch# show file systems
File Systems:

     Size(b)     Free(b)      Type  Flags  Prefixes
*    3612672     1234432     flash     rw   flash:
     3612672     1234432   unknown     rw   zflash:
           -           -    opaque     ro   bs:
       32768       30917     nvram     rw   nvram:
           -           -   network     rw   tftp:
           -           -    opaque     rw   null:
           -           -    opaque     rw   system:
           -           -   network     rw   rcp:

show interface

Use the show interface privileged EXEC command to display the administrative and operational status of a switching (nonrouting) port.

show interface [interface-id | vlan number] [flow-control | status | switchport [allowed-vlan | native-vlan]] | [{begin | exclude | include} expression]

Syntax Description

interface-id

ID of the port number.

vlan number

VLAN number of the management VLAN. Valid IDs are from 1 to 1001.
Do not enter leading zeroes.

flow-control

Displays flowcontrol information for the specified port.

status

(Optional) Display the status of the interface.

switchport

(Optional) Display the administrative and operational status of a switching (nonrouting) port.

allowed-vlan—Display the VLAN IDs that receive and transmit all types of traffic on the trunk port. By default, all VLAN IDs are included.

native-vlan—Display the native VLAN ID for untagged traffic when the port is in 802.1Q trunking mode.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show interface gi0/1 flow-control command.

Switch# show interface gi0/1 flow-control
Any,Input only 

The display shows two values separated by a comma. The first value is the value you configured by using the flowcontrol command or through the Cluster Management Suite (or the default value if you did not configure it). The first value displayed can be one of the following settings:

None—Flow control is not enabled.

Asymmetric—Only the transmit or receive flow control is enabled.

Symmetric—Both the transmit and receive flow control are enabled.

Any—Any type of flow control is supported.

The second value in the display represents the flow control value that is autonegotiated with the link partner and can be one of the following settings:

None—Flow control with the link partner did not occur.

Output only—The interface can only transmit pause frames but not receive any.

Input only—The interface can only receive pause frames but not transmit any.

Output and Input—The interface can transmit and receive pause frames.

The following is sample output from the show interface status command:

Switch# show interface status

Port    Name               Status       Vlan     Duplex Speed   Type
------- ------------------ ------------ -------- ------ ------- ----
Fa0/1                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/2                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/3                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/4                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/5                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/6                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/7                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/8                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/9                      connected    1        A-Full   A-100 100BaseTX/FX
Fa0/10                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/11                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/12                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/13                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/14                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/15                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/16                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/17                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/18                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/19                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/20                     connected    1        A-Full   A-100 100BaseTX/FX
          
Port    Name               Status       Vlan     Duplex Speed   Type
------- ------------------ ------------ -------- ------ ------- ----
Fa0/21                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/22                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/23                     connected    1        A-Full   A-100 100BaseTX/FX
Fa0/24                     connected    1        A-Full   A-100 100BaseTX/FX
Gi0/1                      connected    1          Full    1000 1000BaseT
Gi0/2                      connected    1          Full    1000 1000BaseT

The following is sample output from the show interface fa0/2 switchport command. Table 2-1 describes each field in the display.

Switch# show interface fa0/2 switchport
Name: Fa0/2
Switchport: Enabled
Administrative mode: static access
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: NONE
Pruning VLANs Enabled: NONE

Priority for untagged frames: 0
Override vlan tag priority: FALSE
Voice VLAN: none
Appliance trust: none

Table 2-1 Show Interface fa0/2 Switchport Field Descriptions 

Field
Description

Name

Displays the port name.

Switchport

Displays the administrative and operational status of the port. In this display, the port is in switchport mode.

Administrative Mode

Operational Mode

Displays the administrative and operational mode.

Administrative Trunking Encapsulation

Operation Trunking Encapsulation

Negotiation of Trunking

Displays the administrative and operational encapsulation method. Also displays whether trunking negotiation is enabled.

Access Mode VLAN

Displays the VLAN ID to which the port is configured.

Trunking Native Mode VLAN

Trunking VLANs Enabled

Trunking VLANs Active

Lists the VLAN ID of the trunk that is in native mode. Lists the allowed VLANs on the trunk. Lists the active VLANs on the trunk.

Priority for untagged frames

Displays the port priority on incoming untagged frames.


Related Commands

Command
Description

switchport access

Configures a port as static access.

switchport mode

Configures the VLAN membership mode of a port.

switchport priority default

Provides a default port priority for the incoming untagged frames.


show ip igmp snooping

Use the show ip igmp snooping privileged EXEC command to display the Internet Group Management Protocol (IGMP) snooping configuration of the switch or the VLAN.

show ip igmp snooping | [{begin | exclude | include} expression]

show ip igmp snooping vlan vlan-id | [{begin | exclude | include} expression]

Syntax Description

vlan vlan-id

(Optional) Keyword and variable to specify a VLAN; valid values are 1 to 1001.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Defaults

This command has no default setting.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this command to display snooping characteristics for the switch or for a specific VLAN.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following example shows how to display snooping information for the switch:

Switch# show ip igmp snooping 

vlan 1
----------
  IGMP snooping is globally enabled
  IGMP snooping is enabled on this Vlan
  IGMP snooping immediate-leave is enabled on this Vlan
  IGMP snooping mrouter learn mode is pim-dvmrp on this Vlan
vlan 2
----------
  IGMP snooping is globally enabled
  IGMP snooping is enabled on this Vlan
  IGMP snooping immediate-leave is enabled on this Vlan
  IGMP snooping mrouter learn mode is cgmp on this Vlan
vlan 3
----------
  IGMP snooping is globally enabled
  IGMP snooping is enabled on this Vlan
  IGMP snooping immediate-leave is disabled on this Vlan
  IGMP snooping mrouter learn mode is cgmp on this Vlan
vlan 4
----------
  IGMP snooping is globally enabled
  IGMP snooping is enabled on this Vlan
  IGMP snooping immediate-leave is disabled on this Vlan 
IGMP snooping mrouter learn mode is cgmp on this Vlan
vlan 5
----------
  IGMP snooping is globally enabled
  IGMP snooping is enabled on this Vlan
  IGMP snooping immediate-leave is disabled on this Vlan
  IGMP snooping mrouter learn mode is pim-dvmrp on this Vlan
vlan 33
----------
  IGMP snooping is globally enabled
  IGMP snooping is enabled on this Vlan
  IGMP snooping immediate-leave is disabled on this Vlan
  IGMP snooping mrouter learn mode is pim-dvmrp on this Vlan 

The following example shows how to display snooping information for a specific VLAN:

Switch# show ip igmp snooping vlan 1

vlan 1
----------
  IGMP snooping is globally enabled
  IGMP snooping is enabled on this Vlan
  IGMP snooping immediate-leave is enabled on this Vlan
  IGMP snooping mrouter learn mode is pim-dvmrp on this Vlan 

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping.

ip igmp snooping vlan vlan_id

Enables IGMP snooping on the VLAN interface.

ip igmp snooping vlan immediate-leave

Configures IGMP Immediate-Leave processing.

ip igmp snooping vlan mrouter

Configures a Layer 2 port as a multicast router port.

show mac-address-table multicast

Displays the Layer 2 multicast entries for a VLAN.


show ip igmp snooping mrouter

Use the show ip igmp snooping mrouter privileged EXEC command to display information on dynamically learned and manually configured multicast router ports.

show ip igmp snooping mrouter vlan vlan-id | [{begin | exclude | include} expression]

Syntax Description

vlan vlan-id

(Optional) Keyword and variable to specify a VLAN; valid values are 1 to 1001.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Defaults

This command has no default setting.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You can also use the show mac-address-table multicast command to display entries in the MAC address table for a VLAN that has Internet Group Management Protocol (IGMP) snooping enabled.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following example shows how to display snooping information for VLAN 1.


Note In this example, Fa0/3 is a dynamically learned router port, and Fa0/2 is a configured static router port.


Switch# show ip igmp snooping mrouter vlan 1

Vlan    ports
----    -----
   1    Fa0/2(static), Fa0/3(dynamic) 

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping.

ip igmp snooping vlan

Enables IGMP snooping on the VLAN interface.

ip igmp snooping vlan immediate-leave

Configures IGMP Immediate-Leave processing.

ip igmp snooping vlan mrouter

Configures a Layer 2 port as a multicast router port.

show mac-address-table multicast

Displays the Layer 2 multicast entries for a VLAN.



show mac-address-table

Use the show mac-address-table privileged EXEC command to display the MAC address table.

show mac-address-table [static | dynamic | secure | self | aging-time | count]
[address hw-addr] [interface interface] [vlan vlan-id] | [{begin | exclude | include} expression]

Syntax Description

static

(Optional) Display only the static addresses.

dynamic

(Optional) Display only the dynamic addresses.

secure

(Optional) Display only the secure addresses.

self

(Optional) Display only addresses added by the switch itself.

aging-time

(Optional) Display aging-time for dynamic addresses for all VLANs.

count

(Optional) Display a count for different kinds of MAC addresses.

address hw-addr

(Optional) Display information for a specific address.

interface interface

(Optional) Display addresses for a specific port.

vlan vlan-id

(Optional) Display addresses for a specific VLAN. Valid IDs are from
1 to 1001; do not enter leading zeroes.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command displays the MAC address table for the switch. Specific views can be defined by using the optional keywords and values. If more than one optional keyword is used, all of the conditions must be true in order for that entry to be displayed.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show mac-address-table command:

Switch# show mac-address-table

Dynamic Addresses Count:               9
Secure Addresses (User-defined) Count: 0
Static Addresses (User-defined) Count: 0
System Self Addresses Count:           41
Total MAC addresses:                   50
Non-static Address Table:
Destination Address  Address Type  VLAN  Destination Port
-------------------  ------------  ----  --------------------
0010.0de0.e289       Dynamic          1  FastEthernet0/1
0010.7b00.1540       Dynamic          2  FastEthernet0/5
0010.7b00.1545       Dynamic          2  FastEthernet0/5
0060.5cf4.0076       Dynamic          1  FastEthernet0/1
0060.5cf4.0077       Dynamic          1  FastEthernet0/1
0060.5cf4.1315       Dynamic          1  FastEthernet0/1
0060.70cb.f301       Dynamic          1  FastEthernet0/1
00e0.1e42.9978       Dynamic          1  FastEthernet0/1
00e0.1e9f.3900       Dynamic          1  FastEthernet0/1 

Related Commands

Command
Description

clear mac-address-table

Deletes entries from the MAC address table.


show mac-address-table multicast

Use the show mac-address-table multicast privileged EXEC command to display the Layer 2 multicast entries for the switch or for the VLAN.

show mac-address-table multicast vlan vlan-id [user|igmp-snooping] [count] | [{begin | exclude | include} expression]

Syntax Description

vlan vlan-id

(Optional) Specify a VLAN; valid values are 0 to 1001.

user

(Optional) Display only the user-configured multicast entries.

igmp_snooping

(Optional) Display only entries learned through Internet Group Management Protocol (IGMP) snooping.

count

(Optional) Display total number of entries for the specified criteria instead of the actual entries.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Defaults

This command has no default setting.

Command Modes

Privileged EXEC mode

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Displays the multicast MAC address for the switch.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following example shows how to display the multicast MAC address for the switch:

Switch#show mac-address-table multicast

Vlan    Mac Address     Type    Ports
----    -----------     ----    -----
   1    0100.5e00.0128  IGMP    Fa0/11
   1    0100.5e01.1111  USER    Fa0/5, Fa0/6, Fa0/7, Fa0/11

show ntp associations

Use the show ntp associations privileged EXEC command to display the status of Network Time Protocol (NTP) associations.

show ntp associations [detail] | [{begin | exclude | include} expression]

Syntax Description

detail

(Optional) Show detailed information about each NTP association.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

Detailed descriptions of the information displayed by this command can be found in the NTP specification RFC 1305.

The following is sample output from the show ntp associations command:

Switch# show ntp associations
     address         ref clock     st  when  poll reach  delay  offset    disp
 ~160.89.32.2      160.89.32.1       5    29  1024  377     4.2   -8.59     1.6
+~131.108.13.33    131.108.1.111     3    69   128  377     4.1    3.48     2.3
*~131.108.13.57    131.108.1.111     3    32   128  377     7.9   11.18     3.6
* master (synced), # master (unsynced), + selected, - candidate, ~ configured

show ntp status

Use the show ntp status privileged EXEC command to display the status of the Network Time Protocol (NTP).

show ntp status | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command deletes entries from the global MAC address table. Specific subsets can be deleted by using the optional keywords and values. If more than one optional keyword is used, all of the conditions in the argument must be true for that entry to be deleted.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show ntp status command:

Switch# show ntp status
Clock is synchronized, stratum 4, reference is 131.108.13.57
nominal freq is 250.0000 Hz, actual freq is 249.9990 Hz, precision is 2**19
reference time is AFE2525E.70597B34 (00:10:22.438 PDT Mon Jul 5 1993)
clock offset is 7.33 msec, root delay is 133.36 msec
root dispersion is 126.28 msec, peer dispersion is 5.98 msec

show port group

Use the show port group privileged EXEC command to display the ports that belong to a port group.

show port group [group-number] | [{begin | exclude | include} expression]

Syntax Description

group-number

(Optional) Port group to which the port is assigned.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable group-number is omitted, the show port group command displays all port groups on the switch.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show port group command:

Switch# show port group 1

Group  Interface
-----  ---------------
    1  FastEthernet0/1
    1  FastEthernet0/4

Related Commands

Command
Description

port group

Assigns a port to a Fast EtherChannel or Gigabit EtherChannel port group.


show port monitor

Use the show port monitor privileged EXEC command to display the ports for which Switched Port Analyzer (SPAN) port monitoring is enabled.

show port monitor [interface-id | vlan number] | [{begin | exclude | include} expression]

Syntax Description

interface-id

(Optional) ID of the port number enabled for SPAN.

vlan number

(Optional) VLAN number from 1 to 1001. Do not enter leading zeroes.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable interface is omitted, the show port monitor command displays all monitor ports on the switch.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show port monitor command:

Switch# show port monitor fa0/8

Monitor Port        Port Being Monitored
------------------  --------------------
FastEthernet0/8     FastEthernet0/1
FastEthernet0/8     FastEthernet0/2
FastEthernet0/8     FastEthernet0/3
FastEthernet0/8     FastEthernet0/4 

Related Commands

Command
Description

port monitor

Enables SPAN port monitoring on a port.


show port protected

Use the show port protected privileged EXEC command to display the port protected mode for all ports.

show port protected | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show port protected command:

Switch# show port protected

FastEthernet0/3 is in protected mode
GigabitEthernet1/1 is in protected mode

Related Commands

Command
Description

port protected

Isolates unicast, multicast, and broadcast traffic at Layer 2 from other protected ports on the same switch.


show port security

Use the show port security privileged EXEC command to display the port security settings defined for the port.

show port security [interface-id | vlan number] | [{begin | exclude | include} expression]

Syntax Description

interface-id

(Optional) ID of the port number.

vlan number

(Optional) VLAN number from 1 to 1001. Do not enter leading zeroes.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable interface is omitted, the show port security command displays all secure ports on the switch.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show port security command for fixed port 07:

Switch# show port security fa0/7

Secure Port      Secure Addr    Secure Addr  Security   Security Action
                 Cnt (Current)  Cnt (Max)    Reject Cnt
---------------  -------------  -----------  ---------- ----------------
FastEthernet0/7  0              132          0          Send Trap

Related Commands

Command
Description

port security

Enables port security on a port.


show port storm-control

Use the show port storm-control privileged EXEC command to display the packet-storm control information. This command also displays the action that the switch takes when the thresholds are reached.

show port storm-control [interface] [{broadcast | multicast | unicast | history}] | [{begin | exclude | include} expression]

Syntax Description

interface

(Optional) Port for which information is to be displayed.

broadcast

(Optional) Display broadcast storm information.

multicast

(Optional) Display multicast storm information.

unicast

(Optional) Display unicast storm information.

history

(Optional) Display storm history on a per-port basis.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable interface is omitted, the show port storm-control command displays storm control settings on all ports on the switch.

You can display broadcast, multicast, or unicast packet-storm information by using the corresponding keyword.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show port storm-control command:

Switch# show port storm-control

Interface  Filter State   Trap State     Rising  Falling  Current  Traps Sent
---------  -------------  -------------  ------  -------  -------  ----------
Fa0/1      <inactive>     <inactive>       1000      200        0           0
Fa0/2      <inactive>     <inactive>        500      250        0           0
Fa0/3      <inactive>     <inactive>        500      250        0           0
Fa0/4      <inactive>     <inactive>        500      250        0           0

Related Commands

Command
Description

port storm-control

Enables broadcast, multicast, or unicast storm control on a port.


show proposed

Use the show proposed VLAN database command to display the proposed VLAN database or a selected VLAN from it.

show proposed [vlan-id] | [{begin | exclude | include} expression]

Syntax Description

vlan-id

(Optional) ID of the VLAN in the proposed database. If this variable is omitted, the entire VLAN database displays, included the pruning state and Version 2 mode. Valid IDs are from 1 to 1001; do not enter leading zeroes.

| begin

(Optional) Display begins with the line that matches thespecified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable vlan-id is omitted, the show proposed command displays the entire proposed VLAN database.

The proposed VLAN database is not the running configuration until you use the exit or apply command.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show proposed command:

Switch(vlan)# show proposed
    Name: default
    Media Type: Ethernet
    VLAN 802.10 Id: 100001
    State: Operational
    MTU: 1500
    Translational Bridged VLAN: 1002
    Translational Bridged VLAN: 1003

    Name: fddi-default
    Media Type: FDDI
    VLAN 802.10 Id: 101002
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Translational Bridged VLAN: 1
    Translational Bridged VLAN: 1003

    Name: token-ring-default
    Media Type: Token Ring
    VLAN 802.10 Id: 101003
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Ring Number: 0
    Bridge Number: 1
    Parent VLAN: 1005
    Maximum ARE Hop Count: 7
    Maximum STE Hop Count: 7
    Backup CRF Mode: Disabled
    Translational Bridged VLAN: 1
    Translational Bridged VLAN: 1002

    Name: fddinet-default
    Media Type: FDDI Net
    VLAN 802.10 Id: 101004
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Bridge Number: 1
    STP Type: IBM

    Name: trnet-default
    Media Type: Token Ring Net
    VLAN 802.10 Id: 101005
    State: Operational
    MTU: 1500
    Maximum ARE Hop Count: 7
    Maximum STE Hop Count: 7
    Backup CRF Mode: Disabled
    Translational Bridged VLAN: 1
    Translational Bridged VLAN: 1002

    Name: fddinet-default
    Media Type: FDDI Net
    VLAN 802.10 Id: 101004
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Bridge Number: 1
    STP Type: IBM
    Name: trnet-default
    Media Type: Token Ring Net
    VLAN 802.10 Id: 101005
    State: Operational
    MTU: 1500
    Bridge Type: SRB
    Bridge Number: 1
    STP Type: IBM 

Command
Description

show changes

Displays the differences between the VLAN database currently on the switch and the proposed VLAN database.

show current

Displays the current VLAN database on the switch or a selected VLAN from it.



show rps

Use the show rps privileged EXEC command to display the status of the Cisco Redundant Power System (RPS).

show rps | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show rps command. Table 2-2 describes the possible display output.

Switch# show rps
ACTIVATED

Table 2-2 Show RPS Display Output Description 

Display
Description
Switch RPS LED Color

NA

The RPS is off or not installed.

Off (all switch and RPS models)

ACTIVATED

The internal power supply of the switch is down. The switch is operating through the RPS.

Blinking amber

DEACTIVATED

The RPS is connected, operational, and in active mode. The switch is operating from its own internal power supply.

Solid green

FAULTY

The RPS is connected but not functioning. One of the power supplies in the RPS could be powered down, or a fan on the RPS could have failed, or RPS temperature is too high, or RPS is in standby mode.

Solid amber (all switch and RPS models)

NOT AVAILABLE

The RPS is backing up another switch; power redundancy is lost.

Blinking green


show spanning-tree

Use the show spanning-tree privileged EXEC command to display spanning-tree information for the specified spanning-tree instances.

show spanning-tree [brief] | [summary] | [vlan stp-list] [interface interface-list] | [{begin | exclude | include} expression]

Syntax Description

brief

Display a brief status of the spanning tree.

summary

Display a summary of the spanning-tree states.

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Enter each VLAN ID separated by a space. Valid IDs are from 1 to 1001; do not enter leading zeroes.
Ranges are not supported.

interface interface-list

List of ports for which spanning-tree information is displayed. Enter each port separated by a space. Ranges are not supported.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable stp-list is omitted, the command applies to the Spanning Tree Protocol (STP) instance associated with VLAN 1.

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show spanning-tree summary command:

Switch# show spanning-tree summary

UplinkFast is disabled

Name                 Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1                23       0         0        1          24
-------------------- -------- --------- -------- ---------- ----------
              1 VLAN 23       0         0        1          24

Switch# show spanning-tree brief
VLAN1
  Spanning tree enabled protocol IEEE
  ROOT ID    Priority 32768
             Address 0030.7172.66c4
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec 
VLAN1
  Spanning tree enabled protocol IEEE
  ROOT ID    Priority 32768
             Address 0030.7172.66c4
Port                           Designated
Name    Port ID Prio Cost Sts  Cost  Bridge ID      Port ID
------- ------- ---- ---- ---  ----  -------------- -------
Fa0/11  128.17  128  100  BLK  38    0404.0400.0001 128.17
Fa0/12  128.18  128  100  BLK  38    0404.0400.0001 128.18
Fa0/13  128.19  128  100  BLK  38    0404.0400.0001 128.19
Fa0/14  128.20  128  100  BLK  38    0404.0400.0001 128.20
Fa0/15  128.21  128  100  BLK  38    0404.0400.0001 128.21
Fa0/16  128.22  128  100  BLK  38    0404.0400.0001 128.22
Fa0/17  128.23  128  100  BLK  38    0404.0400.0001 128.23
Fa0/18  128.24  128  100  BLK  38    0404.0400.0001 128.24
Fa0/19  128.25  128  100  BLK  38    0404.0400.0001 128.25
Fa0/20  128.26  128  100  BLK  38    0404.0400.0001 128.26
Fa0/21  128.27  128  100  BLK  38    0404.0400.0001 128.27

Port                           Designated
Name    Port ID Prio Cost Sts  Cost  Bridge ID      Port ID
------- ------- ---- ---- ---  ----  -------------- -------
Fa0/22  128.28  128  100  BLK  38    0404.0400.0001 128.28
Fa0/23  128.29  128  100  BLK  38    0404.0400.0001 128.29
Fa0/24  128.30  128  100  BLK  38    0404.0400.0001 128.30 Hello Time   2 sec  Max Age 20 
sec  Forward Delay 15 sec 

The following is sample output from the show spanning-tree command for VLAN 1:

Switch# show spanning-tree vlan 1

Spanning tree 1 is executing the IEEE compatible Spanning Tree protocol
  Bridge Identifier has priority 32768, address 00e0.1eb2.ddc0
  Configured hello time 2, max age 20, forward delay 15
  Current root has priority 32768, address 0010.0b3f.ac80
  Root port is 5, cost of root path is 10
  Topology change flag not set, detected flag not set, changes 1
  Times:  hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
  Timers: hello 0, topology change 0, notification 0

Interface Fa0/1  in Spanning tree 1 is down
   Port path cost 100, Port priority 128
   Designated root has priority 32768, address 0010.0b3f.ac80
   Designated bridge has priority 32768, address 00e0.1eb2.ddc0
   Designated port is 1, path cost 10
   Timers: message age 0, forward delay 0, hold 0
   BPDU: sent 0, received 0 
...

The following is sample output from the show spanning-tree interface command for port 3:

Switch# show spanning-tree interface fa0/3

Interface Fa0/3 (port 3) in Spanning tree 1 is down
   Port path cost 100, Port priority 128
   Designated root has priority 6000, address 0090.2bba.7a40
   Designated bridge has priority 32768, address 00e0.1e9f.4abf
   Designated port is 3, path cost 410
   Timers: message age 0, forward delay 0, hold 0
   BPDU: sent 0, received 0 

Related Commands

Command
Description

spanning-tree

Enables STP on a VLAN.

spanning-tree forward-time

Sets the forwarding-time for the specified spanning-tree instances.

spanning-tree max-age

Changes the interval between messages the spanning tree receives from the root switch.

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.

spanning-tree protocol

Specifies the STP to be used for specified spanning-tree instances.


show tacacs

Use the show tacacs privileged EXEC command to display various Terminal Access Controller Access Control System Plus (TACACS+) server statistics.

show tacacs | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show tacacs command:

Switch# show tacacs

Server:172.20.128.113/49:opens=4 closes=4 aborts=0 errors=0
        packets in=6 packets out=6
        no connection

show udld

Use the show udld user EXEC command to display UniDirectional Link Detection (UDLD) status for all ports or the specified port.

show udld [interface-id] | [{begin | exclude | include} expression]

Syntax Description

interface-id

(Optional) ID of the port number or a VLAN ID. Valid IDs are from 1 to 1001.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

User EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show udld fa0/11 command. For this display, UDLD is enabled on both ends of the link, and UDLD detects that the link is bidirectional. Table 2-3 describes the fields in this display.

Switch# show udld fa0/11
Interface Fa0/11
Port enable configuration setting: Follows global setting
Operational enable state: Enabled
Current bidirectional state: Bidirectional
Message interval: 60
Message timer: 38
Current operational state: Advertisement
Time out interval: 5
Time out timer: 0
Restart counter: 0
Neighbors counter: 1
Probe counter: 0
No multiple neighbors detected
Current pool id: 1
    ---
    Cache entry 1 (0x69D8E4)
    Device name: aunguyen-1.cisco.com
    Device MAC address: 00:E0:1E:9F:85:80
    Port ID: Fa1/1
    Expiration time: 159
    Cache device ID: 1
    Resynch flag clear
    Current neighbor state: Bidirectional
    Most recent message type received: Probe
    Message interval: 5
        Neighbor echo 1 device: 00:50:0F:08:A4:00
        Neighbor echo 1 port: Fa0/11 

Table 2-3 Show Udld Field Descriptions 

Field
Description

Interface

The interface on the local device configured for UDLD.

Port enable configuration setting

How UDLD is configured on the port. If UDLD is enabled or disabled, the port enable configuration setting is the same as operational enable state. Otherwise, the enable operational setting depends on the global enable setting.

Operational enable state

Operational state that indicates whether UDLD is actually running on this port.

Current bidirectional state

The bidirectional state of the link. An unknown state is displayed if the link is down or if it is connected to an UDLD-incapable device. A bidirectional state is displayed if the link is a normal two-way connection to a UDLD-capable device. All other values indicate miswiring.

Message interval

How often advertisement messages are sent from the local device. Measured in seconds.

Message timer

The length of time before the next advertisement is sent from the local device. Measured in seconds.

Current operational state

The current phase of the UDLD state machine. For a normal bidirectional link, the state machine is most often in the Advertisement phase.

Time out interval

The time period, in seconds, that UDLD waits for echoes from a neighbor device during the detection window.

Time out timer

The remaining time in seconds in the detection window. This setting is meaningful only if UDLD is in the detection phase.

Restart counter

The number of times UDLD sends probe messages in the detection phase.

Neighbors counter

The number of neighbors detected. For point-to-point links, this value should always be one. It is greater than one only when the port is connected to a hub.

Probe counter

The remaining number of probe messages to send in the current detection window. This setting is meaningful only if UDLD is in the detection phase.

Current pool id

An internal index number on the local device.

Cache entry 1

Information from the first cache entry, which contains a copy of echo information received from the neighbor.

Device name

The neighbor device name.

Device MAC address

The neighbor MAC address.

Port ID

The neighbor port ID enabled for UDLD.

Expiration time

The amount of time in seconds remaining before this cache entry is aged out.

Cache device ID

The ID of the cache device.

Resynch flag clear

Indicates that there are no outstanding requests from neighbors to resynchronize cache data.

Current neighbor state

The neighbor's current state. If both the local and neighbor devices are running UDLD normally, the neighbor state and local state should be bidirectional. If the link is down or the neighbor is not UDLD-capable, no cache entries are displayed.

Most recent message type received

The type of message received from the neighbor.

Message interval

The rate, in seconds, at which the neighbor is sending advertisement messages.

Neighbor echo 1 device

The MAC address of the neighbors neighbor from which the echo originated.

Neighbor echo 1 port

The port number ID of the neighbor from which the echo originated.


Related Commands

Command
Description

udld

Enables UDLD on a port.

udld enable

Enables UDLD on all ports on the switch.

udld reset

Resets any interface that has been shut down by UDLD.


show version

Use the show version privileged EXEC command to display version information for the hardware and firmware.

show version | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show version command:

Switch# show version

Cisco Internetwork Operating System Software
IOS (tm) C2950 Software (C2950-C3H2S-M), Experimental Version 12.0(5)WC(1) 
[cchang-switch2_12_0t 845]
Copyright (c) 1986-2000 by cisco Systems, Inc.
Compiled Tue 29-Aug-00 11:27 by cchang
Image text-base: 0x80010000, data-base: 0x802F2000

ROM: Bootstrap program is Commander boot loader

switch uptime is 14 hours, 57 minutes
System returned to ROM by power-on
System image file is "flash:c2950-c3h2s-mz.120.bin"


cisco WS-C2950-12 (RC32300) processor with 22383K bytes of memory.
Last reset from system-reset

Processor is running Enterprise Edition Software
Cluster command switch capable
Cluster member switch capable
12 FastEthernet/IEEE 802.3 interface(s)


32K bytes of flash-simulated non-volatile configuration memory. 
32K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address: 00:01:02:03:04:00
Configuration register is 0xF

show vlan

Use the show vlan privileged EXEC command to display the parameters for all configured VLANs or one VLAN (if the VLAN ID or name is specified) in the administrative domain.

show vlan [brief | id vlan-id | name vlan-name] | [{begin | exclude | include} expression]

Syntax Description

brief

(Optional) Display one line for each VLAN with the VLAN name, status, and its ports.

id vlan-id

(Optional) ID of the VLAN displayed. Valid IDs are from 1 to 1001; do not enter leading zeroes.

name vlan-name

(Optional) Name of the VLAN displayed. The VLAN name is an ASCII string from 1 to 32 characters.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show vlan command:

Switch# show vlan
VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/1, Fa0/2, Fa0/3, Fa0/4,
                                                Fa0/5, Fa0/6, Fa0/7, Fa0/8,
                                                Fa0/9, Fa0/10, Fa0/11, Fa0/12,
                                                Fa0/13, Fa0/14, Fa0/15, Fa0/16,
                                                Fa0/17, Fa0/18, Fa0/19, Fa0/20,
                                                Fa0/21, Fa0/22, Fa0/23, Fa0/24,
                                                Gi0/1, Gi0/2
1002 fddi-default                     active    
1003 token-ring-default               active    
1004 fddinet-default                  active    
1005 trnet-default                    active 



VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- ------ ------
1    enet  100001     1500  -      -      -        -    1002   1003
6    fdnet 100006     1500  -      -      -        ieee 0      0
7    trnet 100007     1500  -      -      5        ieee 0      0
1002 fddi  101002     1500  -      -      -        -    1      1003
1003 tr    101003     1500  1005   3276   -        -    1      1002
1004 fdnet 101004     1500  -      -      1        ibm  0      0
1005 trnet 101005     1500  -      -      15       ibm  0      0

The following is sample output from the show vlan brief command:

Switch# show vlan brief

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/1, Fa0/2, Fa0/5, Fa0/6,
                                                Fa0/7, Fa0/8, Fa0/9, Fa0/10,
                                                Fa0/11, Fa0/12, Fa0/13, Fa0/14,
                                                Fa0/15, Fa0/16, Fa1/1, Fa1/2,
                                                Fa1/3, Fa1/4, Fa2/3, Fa2/4
2    VLAN0002                         active
3    VLAN0003                         active
6    VLAN0006                         active
7    VLAN0007                         active
1002 fddi-default                     active
1003 token-ring-default               active
1004 fddinet-default                  active
1005 trnet-default                    active 

The following is sample output from the show vlan id 6 or show vlan name VLAN006 command:

Switch# show vlan id 6

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
6    VLAN0006                         active

VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- ------ ------
6    fdnet 100006     1500  -      -      -        ieee 0      0 

Related Commands

Command
Description

switchport mode

Configures the VLAN membership mode of a port.

vlan

Configures VLAN characteristics.


show vtp

Use the show vtp privileged EXEC command to display general information about the VLAN Trunk Protocol (VTP) management domain, status, and counters.

show vtp {counters | status} | [{begin | exclude | include} expression]

Syntax Description

counters

Display the VTP counters for the switch.

status

Display general information about the VTP management domain.

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show vtp counters command. Table 2-4 describes each field in the display.

Switch# show vtp counters

VTP statistics:
Summary advertisements received    : 38
Subset advertisements received     : 0
Request advertisements received    : 0
Summary advertisements transmitted : 13
Subset advertisements transmitted  : 3
Request advertisements transmitted : 0
Number of config revision errors   : 0
Number of config digest errors     : 0
Number of V1 summary errors        : 0

VTP pruning statistics:

Trunk            Join Transmitted Join Received    Summary advts received from
                                                   non-pruning-capable device
---------------- ---------------- ---------------- ---------------------------
Fa0/9               827              824              0
Fa0/10              827              823              0 
Fa0/11              827              823              0

Table 2-4 Show VTP Counters Field Descriptions 

Field
Description

Summary Advts Received

Number of summary advertisements received by this switch on its trunk ports. Summary advertisements contain the management domain name, the configuration revision number, the update timestamp and identity, the authentication checksum, and the number of subset advertisements to follow.

Subset Advts Received

Number of subset advertisements received by this switch on its trunk ports. Subset advertisements contain all the information for one or more VLANs.

Request Advts Received

Number of advertisement requests received by this switch on its trunk ports. Advertisement requests normally request information on all VLANs. They can also request information on a subset of VLANs.

Summary Advts Transmitted

Number of summary advertisements sent by this switch on its trunk ports. Summary advertisements contain the management domain name, the configuration revision number, the update timestamp and identity, the authentication checksum, and the number of subset advertisements to follow.

Subset Advts Transmitted

Number of subset advertisements sent by this switch on its trunk ports. Subset advertisements contain all the information for one or more VLANs.

Request Advts Transmitted

Number of advertisement requests sent by this switch on its trunk ports. Advertisement requests normally request information on all VLANs. They can also request information on a subset of VLANs.

No. of Configuration Revision Errors

Number of revision errors.

Whenever you define a new VLAN, delete an existing one, suspend or resume an existing VLAN, or modify the parameters on an existing VLAN, the configuration revision number of the switch increments.

Revision errors increment whenever the switch receives an advertisement whose revision number matches the revision number of the switch, but the MD5 digest values do not match. This error indicates that the VTP password in the two switches is different, or the switches have different configurations.

These errors indicate that the switch is filtering incoming advertisements, which causes the VTP database to become unsynchronized across the network.

No. of Configuration Digest Errors

Number of MD5 digest errors.

Digest errors increment whenever the MD5 digest in the summary packet and the MD5 digest of the received advertisement calculated by the switch do not match. This error usually indicates that the VTP password in the two switches is different. To solve this problem, make sure the VTP password on all switches is the same.

These errors indicate that the switch is filtering incoming advertisements, which causes the VTP database to become unsynchronized across the network.

No. of V1 Summary Errors

Number of version 1 errors.

Version 1 summary errors increment whenever a switch in VTP V2 mode receives a VTP version 1 frame. These errors indicate that at least one neighboring switch is either running VTP version 1 or VTP version 2 with V2-mode disabled. To solve this problem, change the configuration of the switches in VTP V2-mode to disabled.

Summary Advts Received from non-pruning-capable device

Number of VTP summary messages received on the trunk from devices that do not support pruning.


The following is sample output from the show vtp status command. Table 2-5 describes each field in the display.

Switch# show vtp status

VTP Version                     : 2
Configuration Revision          : 1
Maximum VLANs supported locally : 68
Number of existing VLANs        : 7
VTP Operating Mode              : Server
VTP Domain Name                 : test1
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x3D 0x02 0xD4 0x3A 0xC4 0x46 0xA1 0x03
Configuration last modified by 172.20.130.52 at 3-4-93 22:25:

Table 2-5 Show VTP Status Field Descriptions 

Field
Description

VTP Version

Displays the VTP version operating on the switch. By default,
2950 switches implement version 1 but can be set to
version 2.

Configuration Revision

Current configuration revision number on this switch.

Maximum VLANs Supported Locally

Maximum number of VLANs supported locally.

Number of Existing VLANs

Number of existing VLANs.

VTP Operating Mode

Displays the VTP operating mode, which can be server, client, or transparent.

Server: a switch in VTP server mode is enabled for VTP and sends advertisements. You can configure VLANs on it. The switch guarantees that it can recover all the VLAN information in the current VTP database from nonvolatile storage after reboot. By default, every switch is a VTP server.

Client: a switch in VTP client mode is enabled for VTP, can send advertisements, but does not have enough nonvolatile storage to store VLAN configurations. You cannot configure VLANs on it. When a VTP client starts up, it does not transmit VTP advertisements until it receives advertisements to initialize its VLAN database.

Transparent: a switch in VTP transparent mode is disabled for VTP, does not transmit advertisements or learn from advertisements sent by other devices, and cannot affect VLAN configurations on other devices in the network. The switch receives VTP advertisements and forwards them on all trunk ports except the one on which the advertisement was received.

VTP Domain Name

Name that identifies the administrative domain for the switch.

VTP V2 Mode

Displays if VTP version 2 mode is enabled. All VTP version 2 switches operate in version 1 mode by default. Each VTP switch automatically detects the capabilities of all the other VTP devices. A network of VTP devices should be configured to version 2 only if all VTP switches in the network can operate in version 2 mode.

VTP Traps Generation

Displays whether VTP traps are transmitted to a network management station.

MD5 Digest

A 16-byte checksum of the VTP configuration.

Configuration Last Modified

Displays the date and time of the last configuration modification. Displays the IP address of the switch that caused the configuration change to the database.


Related Commands

Command
Description

clear vtp counters

Clears the VTP counters.

vtp

Configures the VTP mode.


show wrr-queue bandwidth

Use the show wrr-queue bandwidth user EXEC command to display the weighted round-robin (WRR) bandwidth allocation for the four class of service (CoS) priority queues.

show wrr-queue bandwidth | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

User EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show wrr-queue bandwidth command.

Switch# show wrr-queue bandwidth 

WRR Queue  :   1   2   3   4

Bandwidth  :  10  20  30  40 

Related Commands

Command
Description

wrr-queue cos-map

Assigns CoS values to the CoS priority queues.

wrr-queue bandwidth

Assigns WRR weights to the four CoS priority queues.

show wrr-queue cos-map

Displays the mapping of the CoS to the priority queues.


show wrr-queue cos-map

Use the show wrr-queue cos-map user EXEC command to display the mapping of the class of service (CoS) priority queues.

show wrr-queue cos-map | [{begin | exclude | include} expression]

Syntax Description

| begin

(Optional) Display begins with the line that matches the specified expression.

| exclude

(Optional) Display excludes lines that match the specified expression.

| include

(Optional) Display includes lines that match the specified expression.

expression

Expression in the output to use as a reference point.


Command Modes

User EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output are displayed.

Examples

The following is sample output from the show wrr-queue cos-map command.

Switch# show wrr-queue cos-map 

CoS Value      :  0  1  2  3  4  5  6  7

Priority Queue :  1  1  2  2  3  3  4  4 

Related Commands

Command
Description

wrr-queue cos-map

Assigns CoS values to the CoS priority queues.

wrr-queue bandwidth

Assigns weighted round-robin (WRR) weights to the four CoS priority queues.

show wrr-queue bandwidth

Displays the WRR bandwidth allocation for the four CoS priority queues.


shutdown

Use the shutdown interface configuration command to disable a port and to shutdown the management VLAN. Use the no form of this command to restart a disabled port or to activate the management VLAN.

shutdown

no shutdown

Syntax Description

This command has no arguments or keywords.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The shutdown command for a port causes it to stop forwarding. You can enable the port with the no shutdown command.

The no shutdown command has no effect if the port is a static-access port assigned to a VLAN that has been deleted, suspended, or shut down. The port must first be a member of an active VLAN before it can be reenabled.

Only one management VLAN interface can be active at a time. The remaining VLANs are shut down. In the show running-config command, the active management VLAN interface is the one with the shutdown command displayed.

Examples

The following examples show how to disable fixed port fa0/8 and how to reenable it:

Switch(config)# interface fa0/8
Switch(config-if)# shutdown

Switch(config-if)# no shutdown

You can verify the previous commands by entering the show interface command in privileged EXEC mode.

Related Commands

Command
Description

management

Shuts down the current management VLAN interface and enables the new management VLAN interface.


shutdown vlan

Use the shutdown vlan global configuration command to shut down (suspend) local traffic on the specified VLAN. Use the no form of this command to restart local traffic on the VLAN.

shutdown vlan vlan-id

no shutdown vlan vlan-id

Syntax Description

vlan-id

ID of the VLAN to be locally shut down. Valid IDs are from 2 to 1001, excluding VLANs defined as default VLANs under the VLAN Trunk Protocol (VTP).
The default VLANs are 1 and 1002-1005. Do not enter leading zeroes.


Defaults

No default is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The shutdown vlan command does not change the VLAN information in VTP database. It shuts down traffic locally, but the switch still advertises VTP information.

Examples

The following example shows how to shutdown traffic on VLAN 2:

Switch(config)# shutdown vlan 2

You can verify the previous command by entering the show vlan command in privileged EXEC mode.

Related Commands

Command
Description

abort

Abandons the proposed new VLAN database, exits VLAN database mode, and returns to privileged EXEC mode.

apply

Implements the proposed new VLAN database, increments the database configuration revision number, propagates it throughout the administrative domain, and remains in VLAN database mode.

exit

Implements the proposed new VLAN database, increments the database configuration number, propagates it throughout the administrative domain, and returns to privileged EXEC mode.

reset

Abandons the proposed VLAN database and remains in VLAN database mode. Resets the proposed database to the currently implemented VLAN database on the switch.

vlan database

Enters VLAN database mode from the command-line interface (CLI).


snmp-server enable traps vlan-membership

Use the snmp-server enable traps vlan-membership global configuration command to enable SNMP notification for VLAN Membership Policy Server (VMPS) changes. Use the no form of this command to disable the VMPS trap notification.

snmp-server enable traps vlan-membership

no snmp-server enable traps vlan-membership

Syntax Description

This command has no arguments or keywords.

Defaults

SNMP traps for VMPS are disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Specify the host that receives the traps by using the snmp-server host command.

Examples

The following example shows how to enable VMPS to send trap notifications:

Switch(config)# snmp-server enable trap vlan-membership

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

snmp-server host

Specifies the host that receives SNMP traps.


snmp-server enable traps vtp

Use the snmp-server enable traps vtp global configuration command to enable SNMP notification for VLAN Trunk Protocol (VTP) changes. Use the no form of this command to disable VTP trap notification.

snmp-server enable traps vtp

no snmp-server enable traps vtp

Syntax Description

This command has no arguments or keywords.

Defaults

SNMP traps for VTP are disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Specify the host that receives the traps by using the snmp-server host command.

Examples

The following example shows how to enable VTP to send trap notifications:

Switch(config)# snmp-server enable trap vtp

You can verify the previous command by entering the show vtp status or show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

show vtp status

Displays general information about the VTP management domain and status.

snmp-server host

Specifies the host that receives SNMP traps.


snmp-server host

Use the snmp-server host global configuration command to specify the host that receives SNMP traps. Use the no form of this command to remove the specified host.

snmp-server host host-address community-string [c2900 | config | snmp | tty | udp-port port-number | vlan-membership | vtp]

no snmp-server host host-address community-string

Syntax Description

host-address

IP address or name of the SNMP trap host.

community-string

Password-like community string sent with the trap operation

c2900

(Optional) Send SNMP 2950 switch traps.

config

(Optional) Send SNMP configuration traps.

snmp

(Optional) Send SNMP-type traps.

tty

(Optional) Send Cisco enterprise-specific traps when a Transmission Control Protocol (TCP) connection closes

udp-port port-number

(Optional) UDP port of the host to use. The default is 162.

vlan-membership

(Optional) Send SNMP VLAN Membership Policy Server (VMPS) traps

vtp

(Optional) Send SNMP VLAN Trunk Protocol (VTP) traps.


Defaults

The SNMP trap host address and community string are not defined.

Traps are disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use the snmp-server host command with the snmp-server enable traps commands to generate traps.

Examples

The following example shows how to configure an SNMP host to receive VTP traps:

Switch(config)# snmp-server host 172.20.128.178 traps vtp

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

snmp-server enable traps vlan-membership

Enables SNMP notification for VMPS changes.

snmp-server enable traps vtp

Enables SNMP notification for VTP changes.


spanning-tree

Use the spanning-tree global configuration command to enable Spanning Tree Protocol (STP) on a VLAN. Use the no form of the command to disable STP on a VLAN.

spanning-tree [vlan stp-list]

no spanning-tree [vlan stp-list]

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.


Defaults

STP is enabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Disabling STP causes the VLAN or list of VLANs to stop participating in STP. Ports that are administratively down remain down. Received Bridge Protocol Data Units (BPDUs) are forwarded like other multicast frames. The VLAN does not detect and prevent loops when STP is disabled.

You can disable STP on a VLAN that is not currently active, and verify the change by using the privileged EXEC show running-config or the show spanning-tree vlan stp-list command. The setting takes effect when the VLAN is activated.

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can enable STP on a VLAN that has no ports assigned to it.

Examples

The following example shows how to disable STP on VLAN 5:

Switch(config)# no spanning-tree vlan 5

You can verify the previous command by entering the show spanning-tree command in privileged EXEC mode. In this instance, VLAN 5 does not appear in the list.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree forward-time

Sets the forwarding-time for the specified spanning-tree instances.

spanning-tree max-age

Changes the interval between messages the spanning tree receives from the root switch.

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.

spanning-tree protocol

Specifies the STP protocol to be used for specified spanning-tree instances.


spanning-tree cost

Use the spanning-tree cost interface configuration command to set the path cost for Spanning Tree Protocol (STP) calculations. In the event of a loop, spanning tree considers the path cost when selecting an interface to place into the forwarding state. Use the no form of this command to return to the default value.

spanning-tree [vlan stp-list] cost cost

no spanning-tree [vlan stp-list] cost

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

cost

Path cost can range from 1 to 65535, with higher values indicating higher costs. This range applies whether or not the IEEE STP has been specified


Defaults

The default path cost is computed from the interface bandwidth setting. The following are IEEE default path cost values:

10 Mbps - 100

100 Mbps - 19

155 Mbps - 14

1 Gbps - 4

10 Gbps - 2

Speeds greater than 10 Gbps - 1

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can set a cost for a port or on a VLAN that does not exist. The setting takes effect when the VLAN exists.

Examples

The following example shows how to set a path cost value of 64 for VLAN 1:

Switch(config-if)# spanning-tree vlan 1 cost 64

You can verify the previous command by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree portfast

Enables the Port Fast feature on a port in all its associated VLANs.

spanning-tree priority

Configures the switch priority for the specified spanning-tree instance.


spanning-tree forward-time

Use the spanning-tree forward-time global configuration command to set the forwarding-time for the specified spanning-tree instances. The forwarding time determines how long each of the listening and learning states last before the port begins forwarding. Use the no form of this command to return to the default value.

spanning-tree [vlan stp-list] forward-time seconds

no spanning-tree [vlan stp-list] forward-time

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

seconds

Forward-delay interval from 4 to 200 seconds.


Defaults

The default forwarding-time for IEEE Spanning Tree Protocol (STP) is 15 seconds. The default for IBM STP is 4 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can set the forwarding-time on a VLAN that has no ports assigned to it. The setting takes effect when you assign ports to it.

Examples

The following example shows how to set the spanning-tree forwarding time to 18 seconds for VLAN 20:

Switch(config)# spanning-tree vlan 20 forward-time 18

You can verify the previous command by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree max-age

Changes the interval between messages the spanning tree receives from the root switch.

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.

spanning-tree protocol

Specifies the STP protocol to be used for specified spanning-tree instances.


spanning-tree hello-time

Use the spanning-tree hello-time global configuration command to specify the interval between hello Bridge Protocol Data Units (BPDUs). Use the no form of this command to return to the default interval.

spanning-tree [vlan stp-list] hello-time seconds

no spanning-tree [vlan stp-list] hello-time

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

seconds

Interval from 1 to 10 seconds.


Defaults

The default hello time for IEEE Spanning Tree Protocol (STP) and IBM STP is 2 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can set the hello time on a VLAN that has no ports assigned to it. The setting takes effect when you assign ports to it.

Examples

The following example shows how to set the spanning-tree hello-delay time to 3 seconds for VLAN 20:

Switch(config)# spanning-tree vlan 20 hello-time 3

You can verify the previous command by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree

Enables STP on a VLAN.

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.

spanning-tree protocol

Specifies the STP protocol to be used for specified spanning-tree instances.


spanning-tree max-age

Use the spanning-tree max-age global configuration command to change the interval between messages the spanning tree receives from the root switch. If a switch does not receive a Bridge Protocol Data Unit (BPDU) message from the root switch within this interval, it recomputes the Spanning Tree Protocol (STP) topology. Use the no form of this command to return to the default interval.

spanning-tree [vlan stp-list] max-age seconds

no spanning-tree [vlan stp-list] max-age

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

seconds

Interval the switch waits between receiving BPDUs from the root switch.
Enter a number from 6 to 200.


Defaults

The default max-age for IEEE STP is 20 seconds. The default for IBM STP is 10 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The max-age setting must be greater than the hello-time setting.

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can set the max-age on a VLAN that has no ports assigned to it. The setting takes effect when you assign ports to the VLAN.

Examples

The following example shows how to set spanning-tree max-age to 30 seconds for VLAN 20:

Switch(config)# spanning-tree vlan 20 max-age 30

The following example shows how to reset the max-age parameter to the default value for spanning-tree instances 100 through 102:

Switch(config)# no spanning-tree vlan 100 101 102 max-age

You can verify the previous commands by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree forward-time

Sets the forwarding-time for the specified spanning-tree instances.

spanning-tree hello-time

Specifies the interval between hello Bridge Protocol Data Units (BPDUs).

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.

spanning-tree protocol

Specifies the STP protocol to be used for specified spanning-tree instances.


spanning-tree portfast

Use the spanning-tree portfast interface configuration command to enable the Port Fast feature on a port in all its associated VLANs. When the Port Fast feature is enabled, the port changes directly from a blocking state to a forwarding state without making the intermediate Spanning Tree Protocol (STP) status changes. Use the no form of this command to return the port to default operation.

spanning-tree portfast

no spanning-tree portfast

Syntax Description

This command has no keywords or arguments.

Defaults

The Port Fast feature is disabled; however, it is automatically enabled on dynamic-access ports.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use this feature only on ports that connect to end stations.

This feature affects all VLANs on the port.

A port with the Port Fast feature enabled is moved directly to the spanning-tree forwarding state.

Examples

The following example shows how to enable the Port Fast feature on fixed port 2.

Switch(config-if)# spanning-tree portfast fa0/2

You can verify the previous commands by entering the show running-config in privilege EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.


spanning-tree port-priority

Use the spanning-tree port-priority interface configuration command to configure a port priority, which is used when two switches tie for position as the root switch. Use the no form of this command to return to the default value.

spanning-tree [vlan stp-list] port-priority port-priority

no spanning-tree [vlan stp-list] port-priority

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

port-priority

Number from 0 to 255. The lower the number, the higher the priority.


Defaults

The default port-priority for IEEE STP and IBM STP is 128.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can set the port priority on a VLAN that has no ports assigned to it. The setting takes effect when you assign ports to the VLAN.

Examples

The following example shows how to increase the likelihood that the spanning-tree instance 20 is chosen as the root switch on port fa0/2:

Switch(config)# interface fa0/2
Switch(config-if)# spanning-tree vlan 20 port-priority 0

You can verify the previous commands by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree protocol

Specifies the STP protocol to be used for specified spanning-tree instances.


spanning-tree priority

Use the spanning-tree priority global configuration command to configure the switch priority for the specified spanning-tree instance. This changes the likelihood that the switch is selected as the root switch. Use the no form of this command to revert to the default value.

spanning-tree [vlan stp-list] priority bridge-priority

no spanning-tree [vlan stp-list] priority

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

bridge-priority

A number from 0 to 65535. The lower the number, the more likely the switch will be chosen as root.


Defaults

The default bridge priority for IEEE STP and IBM STP is 32768.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can configure the switch priority on a VLAN that has no ports assigned to it. The setting takes effect when you assign ports to the VLAN.

Examples

The following example shows how to set the spanning-tree priority to 125 for a list of VLANs:

Switch(config)# spanning-tree vlan 20 100 101 102 priority 125

You can verify the previous command by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree forward-time

Sets the forwarding-time for the specified spanning-tree instances.

spanning-tree hello-time

Specifies the interval between hello Bridge Protocol Data Units (BPDUs).

spanning-tree max-age

Changes the interval between messages the spanning tree receives from the root switch.

spanning-tree protocol

Specifies the STP protocol to be used for specified spanning-tree instances.


spanning-tree protocol

Use the spanning-tree protocol global configuration command to specify the Spanning Tree Protocol (STP) to be used for specified spanning-tree instances. Use the no form of this command to use the default protocol.

spanning-tree [vlan stp-list] protocol {ieee | ibm}

no spanning-tree [vlan stp-list] protocol

Syntax Description

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

ieee

IEEE Ethernet STP.

ibm

IBM STP.


Defaults

The default protocol is ieee.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Changing the spanning-tree protocol command causes STP parameters to change to default values of the new protocol.

If the variable stp-list is omitted, this command applies to the STP instance associated with VLAN 1.

You can change the protocol on a VLAN that has no ports assigned to it. The setting takes effect when you assign ports to it.

Examples

The following example shows how to change the STP protocol for VLAN 20 to the IBM version of STP:

Switch(config)# spanning-tree vlan 20 protocol ibm

You can verify the previous command by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree

Enables STP on a VLAN.

spanning-tree forward-time

Sets the forwarding-time for the specified spanning-tree instances.

spanning-tree max-age

Changes the interval between messages the spanning tree receives from the root switch.

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.


spanning-tree rootguard

Use the spanning-tree rootguard interface configuration command to enable the root guard feature for all the VLANs associated with the selected port. Root guard restricts which port is allowed to be the Spanning Tree Protocol (STP) root port or the path-to-the root for the switch. The root port provides the best path from the switch to the root switch. Use the no form of this command to disable this feature.

spanning-tree rootguard

no spanning-tree rootguard

Syntax Description

This command has no keywords or arguments.

Defaults

The root guard feature is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When the root guard feature is enabled, if spanning-tree calculations cause a port to be selected as the root port, the port transitions to the root-inconsistent (blocked) state to prevent the customer's switch from becoming the root switch or being in the path to the root.

When the no spanning-tree rootguard command is executed, the root guard feature is disabled for all VLANs on the selected port. If this port is in the root-inconsistent (blocked) state, the port automatically transitions to the listening state.

Do not enable the root guard on ports that will be used by the UplinkFast feature. With UplinkFast, the backup ports (in the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the backup ports used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and prevented from reaching the forwarding state.

Examples

The following example shows how to enable the root guard feature on all the VLANs associated with interface fa0/3:

Switch(config)# interface fa0/3
Switch(config-if)# spanning-tree rootguard

You can verify the previous commands by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

show running-config

Displays the current operating configuration.

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.

spanning-tree cost

Sets the path cost for STP calculations. In the event of a loop, spanning tree considers the path cost when selecting an interface to place into the forwarding state.

spanning-tree port-priority

Configures a port priority, which is used when two switches tie for position as the root switch.

spanning-tree priority

Configures the switch priority for the specified spanning-tree instance and affects the likelihood that the switch is selected as the root switch.


spanning-tree uplinkfast

Use the spanning-tree uplinkfast global configuration command to accelerate the choice of a new root port when a link or switch fails or when Spanning Tree Protocol (STP) reconfigures itself. Use the no form of this command to return to the default value.

spanning-tree uplinkfast [max-update-rate pkts-per-second]

no spanning-tree uplinkfast [max-update-rate pkts-per-second]

Syntax Description

max-update-rate pkts-per-second

The number of packets per second at which stations address update packets are sent. The range is 0 to 1000.


Defaults

UplinkFast is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When you enable UplinkFast, it is enabled for the entire switch and cannot be enabled for individual VLANs.

When you enable UplinkFast, the bridge priority of all VLANs is set to 49152, and the path cost of all ports and VLAN trunks is increased by 3000. This change reduces the chance that the switch will become the root switch.

When you disable UplinkFast, the bridge priorities of all VLANs and path costs are set to their default values.

Do not enable the root guard on ports that will be used by the UplinkFast feature. With UplinkFast, the backup ports (in the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the backup ports used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and prevented from reaching the forwarding state.

Examples

The following command shows how to enable UplinkFast:

Switch(config)# spanning-tree uplinkfast 

You can verify the previous command by entering the show spanning-tree command in privileged EXEC mode.

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree information for the specified spanning-tree instances.


speed

Use the speed interface configuration command to specify the speed of a Fast Ethernet port. Use the no form of this command to return the port to its default value.

speed {10 | 100 | 1000 | auto}

no speed

Syntax Description

10

Port runs at 10 Mbps.

100

Port runs at 100 Mbps.

1000

Port runs at 1000 Mbps.

auto

Port automatically detects whether it should run at 10 or 100 Mbps on
Fast Ethernet ports.


Defaults

For Fast Ethernet ports, the default is auto.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Certain ports can be configured to be either 10 or 100 Mbps. Applicability of this command is hardware-dependent.

If the speed is set to auto, the switch negotiates with the device at the other end of the link for the speed setting and then forces the speed setting to the negotiated value. The duplex setting remains as configured on each end of the link, which could result in a duplex setting mismatch.

For Gigabit Ethernet ports, the speed can be configured at 10, 100, or 1000 Mbps.


Note The Gigabit Ethernet ports can operate in either half- or full-duplex mode when they are set to 10 or 100 Mbps, but when they are set to 1000 Mbps, they can only operate in the full-duplex mode.


If both the speed and duplex are set to specific values, autonegotiation is disabled.


Note For guidelines on setting the switch speed and duplex parameters, see the Catalyst 2950 Desktop Switch Software Configuration Guide.


Examples

The following example shows how to set port 1 to 100 Mbps:

Switch(config)# interface fastethernet2/1
Switch(config-if)# speed 100

You can verify the previous commands by entering the show running-config in privilege EXEC mode.

Related Commands

Command
Description

duplex

Specifies the duplex mode of operation for Fast Ethernet and Gigabit Ethernet ports.


switchport access

Use the switchport access interface configuration command to configure a port as a static-access or dynamic-access port. If the mode is set to access, the port operates as a member of the configured VLAN. If set to dynamic, the port starts discovery of VLAN assignment based on the incoming packets it receives. Use the no form of this command to reset the access mode to the default VLAN for the switch.

switchport access vlan vlan-id

no switchport access vlan vlan-id

Syntax Description

vlan vlan-id

ID of the VLAN. Valid IDs are from 1 to 1001. Do not enter leading zeroes.


Defaults

All ports are in static-access mode in VLAN 1.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The port must be in access mode before the switchport access vlan vlan-id or switchport access vlan command can take effect. For more information, see the switchport mode.

An access port can be assigned to only one VLAN.

When the no switchport access vlan form is used, the access mode is reset to static access on VLAN 1.

Examples

The following example shows how to assign a port already in access mode to VLAN 2 (instead of the default VLAN 1):

Switch(config-if)# switchport access vlan 2

You can verify the previous commands by entering the show interface interface-id switchport command in privileged EXEC mode and examining information in the Administrative Mode and Operational Mode rows.

Related Commands

Command
Description

switchport mode

Configures the VLAN membership mode of a port.


switchport mode

Use the switchport mode interface configuration command to configure the VLAN membership mode of a port. Use the no form of this command to reset the mode to the appropriate default for the device.

switchport mode {access | trunk}

no switchport mode {access | trunk}

Syntax Description

access

Set the port to access mode (static-access). The port operates as a nontrunking, single VLAN interface that transmits and receives nonencapsulated frames. An access port can be assigned to only one VLAN.

trunk

Set the port to a trunking VLAN Layer-2 interface. The port transmits and receives encapsulated (tagged) frames that identify the VLAN of origination. A trunk is a point-to-point link between two switches or between a switch and a router.


Defaults

All ports are static-access ports in VLAN 1.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Configuration by using the access or trunk keywords takes affect only when the port is changed to the corresponding mode by using the switchport mode command. The static-access and trunk configurations are saved, but only one configuration is active at a time.

The no switchport mode form resets the mode to static access.

Trunk ports cannot coexist on the same switch.

The following example shows how to configure a port for access mode:

Switch(config-if)# switchport mode access

The following example shows how to configure a port for trunk mode:

Switch(config-if)# switchport mode trunk

You can verify the previous commands by entering the show interface interface-id switchport command in privileged EXEC mode and examining information in the Administrative Mode and Operational Mode rows.

Related Commands

Command
Description

switchport access

Configures a port as a static-access port.


switchport priority

Use the switchport priority interface configuration command to set a port priority for the incoming untagged frames or the priority of frames received by the appliance connected to the specified port. Use the no form of this command to return the setting to its default.

switchport priority {default default-priority-id | extend {cos value | none | trust} | override}

no switchport priority {default default-priority-id | extend | override}

Syntax Description

default-priority-id

The priority number for untagged traffic. The priority is a number from
0 to 7. Seven is the highest priority.

extend

Set the 802.1p priority of the appliance.

cos value—Override the 802.1p priority of devices connected to the appliance. The cos value is a number from 0 to 7. Seven is the highest priority.

none—The appliance is not instructed what to do with the priority.

trust—Specify that the appliance should trust (honor) the received 802.1p priority from devices connected to it.

override

Override the priority of tagged frames with the default value.


Defaults

The port priority is not set, and the default value for untagged frames received on the port is zero.

The appliance connected to the port is not instructed (none) what to do with the priority.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The default port priority applies if the incoming frame is an untagged frame received from a VLAN trunk or static-access port. This port priority does not apply to IEEE 802.1Q VLAN tagged frames. If the incoming frame is an IEEE 802.1Q VLAN tagged frame, IEEE 802.1p User Priority bits is used.

Examples

The following example shows how to set a default priority on port 3.

Switch(config)# interface fa0/3
Switch(config-if)# switchport priority default 7

All untagged frames received from this port will have the same priority value. You can verify the previous commands by entering the show interface interface-id switchport command in privileged EXEC mode.

The following example shows how to configure the appliance connected to the specified port to honor the received 802.1p priority:

Switch(config-if)# switchport priority extend trust

You can verify the previous command by entering the show interface interface-id switchport command in privileged EXEC mode.

Related Commands

Command
Description

show interface

Displays the administrative and operational status of a switching (nonrouting) port.

switchport access

Configures a port as a static-access port.

switchport mode

Configures the VLAN membership mode of a port.


switchport trunk allowed vlan

Use the switchport trunk allowed vlan interface configuration command to control which VLANs can receive and transmit traffic on the trunk. Use the no form of this command to reset the allowed list to the default value.

switchport trunk allowed vlan {add vlan-list | all | except vlan-list | remove vlan-list}

no switchport trunk allowed vlan

Syntax Description

add vlan-list

List of VLAN IDs to add. Valid IDs are from 1 to 1001. Separate nonconsecutive VLAN IDs with a comma and no spaces; use a hyphen to designate a range of IDs. Do not enter leading zeroes.

all

Add all VLAN IDs to the list.

except vlan-list

List of exception VLAN IDs VLANs are added except the ones specified). Valid IDs are from 1 to 1001. Separate nonconsecutive VLAN IDs with a comma and no spaces; use a hyphen to designate a range of IDs. Do not enter leading zeroes.

remove vlan-list

List of VLAN IDs to remove. Valid IDs are from 1 to 1001. Separate nonconsecutive VLAN IDs with a comma and no spaces; use a hyphen to designate a range of IDs. Do not enter leading zeroes.


Defaults

All VLANs are included in the allowed list.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When the no switchport trunk allowed vlan form is used, the allowed list is reset to the default list, which includes all VLANs.

In the variable vlan-list, separate nonconsecutive VLAN IDs with a comma; use a hyphen to designate a range of IDs. You cannot remove VLAN 1 or 1002 to 1005 from the list.

A trunk port cannot be a secure port or a monitor port. However, a static-access port can monitor a VLAN on a trunk port. The VLAN monitored is the one associated with the static-access port.

Examples

The following example shows how to add VLANs 1, 2, 5, and 6 to the allowed list:

Switch(config-if)# switchport trunk allowed vlan add 1,2,5,6

You can verify the previous command by entering the show interface interface-id switchport command in privileged EXEC mode.

Related Commands

Command
Description

switchport mode

Configures the VLAN membership mode of a port.

switchport trunk encapsulation

Sets the encapsulation format on the trunk port.

switchport trunk native

Sets the native VLAN for untagged traffic when in 802.1Q trunking mode.


switchport trunk native

Use the switchport trunk native interface configuration command to set the native VLAN for untagged traffic when in 802.1Q trunking mode. Use the no form of this command to reset the native VLAN to the default.

switchport trunk native vlan vlan-id

no switchport trunk native

Syntax Description

vlan vlan-id

ID of the VLAN that is sending and receiving untagged traffic on the trunk port. Valid IDs are from 1 to 1001. Do not enter leading zeroes.


Defaults

VLAN 1 is the default native VLAN ID on the port.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

All untagged traffic received on the 802.1Q trunk port is forwarded with the native VLAN configured for the port.

If a packet has a VLAN ID that is the same as the sending port native VLAN ID, the packet is transmitted untagged; otherwise, the switch transmits the packet with a tag.

Examples

The following example shows how to configure VLAN 3 as the default port to send all untagged traffic:

Switch(config-if)# switchport trunk native vlan 3

You can verify the previous command by entering the show interface interface-id switchport command in privileged EXEC mode.

Related Commands

Command
Description

switchport mode

Configures the VLAN membership mode of a port.

switchport trunk allowed vlan

Controls which VLANs can receive and transmit traffic on the trunk.

switchport trunk encapsulation

Sets the encapsulation format on the trunk port.


tacacs-server attempts

Use the tacacs-server attempts global configuration command to control the number of login attempts that can be made on a line set up for Terminal Access Controller Access Control System (TACACS), Extended TACACS, or TACACS+ verification. Use the no form of this command to disable this feature and restore the default.

tacacs-server attempts count

no tacacs-server attempts

Syntax Description

count

Integer that sets the number of attempts. The range is from 1 to 1000.


Defaults

The default number of login attempts is 3.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Examples

The following example shows how to change the login attempt to just one:

Switch(config)# tacacs-server attempts 1

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

enable use-tacacs

Enables the use of TACACS to determine whether a user can access the privileged command level.

login tacacs

Configures the switch to use TACACS user authentication.

show tacacs

Displays various TACACS+ server statistics.

tacacs-server directed-request

Sends only a username to a specified server when a direct request is issued in association with TACACS, Extended TACACS, and TACACS+.

tacacs-server host

Specifies a TACACS, Extended TACACS, or TACACS+ host.

tacacs-server key

Sets the authentication encryption key used for all TACACS+ communications between the access server and the TACACS+ daemon.

tacacs-server last-resort

Causes the network access server to request the privileged password as verification for TACACS or Extended TACACS or to allow successful login without further user input.

tacacs-server timeout

Sets the interval that the server waits for a TACACS, Extended TACACS, or TACACS+ server to reply.


tacacs-server directed-request

Use the tacacs-server directed-request global configuration command to send only a username to a specified server when a direct request is issued in association with Terminal Access Controller Access Control System (TACACS), Extended TACACS, and TACACS+. Use the no form of this command to send the whole string, both before and after the @ symbol.

tacacs-server directed-request

no tacacs-server directed-request

Syntax Description

This command has no arguments or keywords.

Defaults

The directed-request feature is enabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command sends only the portion of the username before the @ symbol to the host specified after the @ symbol. In other words, with the directed-request feature enabled, you can direct a request to any of the configured servers, and only the username is sent to the specified server.

Using no tacacs-server directed-request causes the whole string, both before and after the @ symbol, to be sent to the default TACACS server. When the directed-request feature is disabled, the router queries the list of servers, starting with the first one in the list. It sends the whole string and accepts the first response it gets from the server. The tacacs-server directed-request command is useful for sites that have developed their own TACACS server software that parses the whole string and makes decisions based on it.

With tacacs-server directed-request enabled, only configured TACACS servers can be specified by the user after the @ symbol. If the host name specified by the user does not match the IP address of a TACACS server configured by the administrator, the user input is rejected.

Use no tacacs-server directed-request to disable the ability of the user to choose between configured TACACS servers and to cause the entire string to be passed to the default server.

Examples

The following example shows how to pass the entire user input to the default TACACS server:

Switch(config)# no tacacs-server directed-request

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

enable use-tacacs

Enables the use of TACACS to determine whether a user can access the privileged command level.

login tacacs

Configures the switch to use TACACS user authentication.

show tacacs

Displays various TACACS+ server statistics.

tacacs-server directed-request

Sends only a username to a specified server when a direct request is issued in association with TACACS, Extended TACACS, and TACACS+.

tacacs-server host

Specifies a TACACS, Extended TACACS, or TACACS+ host.

tacacs-server key

Sets the authentication encryption key used for all TACACS+ communications between the access server and the TACACS+ daemon.

tacacs-server last-resort

Causes the network access server to request the privileged password as verification for TACACS or Extended TACACS or to allow successful login without further user input.

tacacs-server timeout

Sets the interval that the server waits for a TACACS, Extended TACACS, or TACACS+ server to reply.


tacacs-server dns-alias-lookup

Use the tacacs-server dns-alias-lookup global configuration command to enable IP Domain Name System alias lookup for Terminal Access Controller Access Control System Plus (TACACS+). Use the no form of this command to disable this feature.

tacacs-server dns-alias-lookup

no tacacs-server dns-alias-lookup

Syntax Description

This command has no keywords or arguments.

Defaults

The DNS alias lookup is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Examples

The following example shows how to enable the IP DNS alias lookup:

Switch(config)# tacacs-server dns-alias-lookup

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

ip domain-name

Defines a default domain name that is used to complete unqualified host names (names without a dotted-decimal domain name).

ip name-server

Specifies the address of one or more name servers to use for name and address resolution.


tacacs-server extended

Use the tacacs-server extended global configuration command to enable an Extended Terminal Access Controller Access Control System (TACACS) mode. Use the no form of this command to disable the mode.

tacacs-server extended

no tacacs-server extended

Syntax Description

This command has no arguments or keywords.

Defaults

The Extended TACACS mode is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command initializes Extended TACACS. To initialize authentication, authorization, and accounting (AAA) and TACACS+, use the aaa new-model command.

Examples

The following example shows how to enable Extended TACACS mode:

Switch(config)# tacacs-server extended

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

tacacs-server host

Use the tacacs-server host global configuration command to specify a Terminal Access Controller Access Control System (TACACS), Extended TACACS, or TACACS+ host. Use the no form of this command to delete the specified name or address.

tacacs-server host hostname [single-connection] [port integer] [timeout integer] [key string]

no tacacs-server host hostname

Syntax Description

hostname

Name or IP address of the host.

single-connection

(Optional) Specify that the switch maintain a single open connection for confirmation from an authentication, authorization, and accounting (AAA) and TACACS+ server (CiscoSecure Release 1.0.1 or later). This command contains no autodetect and fails if the specified host is not running a CiscoSecure daemon.

port integer

(Optional) Specify a server port number. The range is from 1 to 65535.

timeout integer

(Optional) Specify a timeout value. This overrides the global timeout value set with the tacacs-server timeout command for this server only. The timeout is an integer in seconds.The range is from 1 to 300 seconds.

key string

(Optional) Specify an authentication and encryption key. This key must match the key used by the TACACS+ daemon. Specifying this key overrides the key set by the global configuration tacacs-server key command for this server only. The key string is a character string specifying the authentication and encryption key.


Defaults

No host is specified.

The default port number is 49.

The default timeout is 5 seconds.

No key string is specified.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

You can use multiple tacacs-server host commands to specify additional hosts. The Cisco IOS software searches for hosts in the order in which you specify them. Use the single-connection, port, timeout, and key options only when running an AAA/TACACS+ server.

Because some of the parameters of the tacacs-server host command override global settings made by the tacacs-server timeout and tacacs-server key commands, you can use this command to enhance security on your network by uniquely configuring individual switches.

Examples

The following example shows how to specify a TACACS host named Sea_Change:

Switch(config)# tacacs-server host Sea_Change

You can verify the previous command by entering the show running-config command in privileged EXEC mode.


The following example shows how to specify that the switch consult the CiscoSecure TACACS+ host named Sea_Cure on port number 51 for AAA confirmation. The timeout value for requests on this connection is 3 seconds; the encryption key is a_secret.

Switch(config)# tacacs-server host Sea_Cure single-connection port 51 timeout 3 key 
a_secret

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

login tacacs

Configures the switch to use TACACS user authentication.

tacacs-server key

Sets the authentication encryption key used for all TACACS+ communications between the access server and the TACACS+ daemon.

tacacs-server timeout

Sets the interval that the server waits for a TACACS, Extended TACACS, or TACACS+ server to reply.


tacacs-server key

Use the tacacs-server key global configuration command to set the authentication encryption key used for all Terminal Access Controller Access Control System Plus (TACACS+) communications between the access server and the TACACS+ daemon. Use the no form of the command to disable the key.

tacacs-server key key

no tacacs-server key [key]

Syntax Description

key

Key used to set authentication and encryption. This key must match the key used on the TACACS+ daemon.


Defaults

No key is specified.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

After enabling authentication, authorization, and accounting (AAA) with the aaa new-model command, you must set the authentication and encryption key by using the tacacs-server key command.

The key entered must match the key used on the TACACS+ daemon. All leading spaces are ignored; spaces within and at the end of the key are not. If you use spaces in your key, do not enclose the key in quotation marks unless the quotation marks themselves are part of the key.

Examples

The following example shows how to set the authentication and encryption key to dare to go:

Switch(config)# tacacs-server key dare to go

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

aaa new-model

Enables the AAA access control model.

tacacs-server host

Specifies a TACACS, Extended TACACS, or TACACS+ host.


tacacs-server last-resort

Use the tacacs-server last-resort global configuration command to cause the network access server to request the privileged password as verification for Terminal Access Controller Access Control System (TACACS) or Extended TACACS or to allow successful log in without further user input. Use the no form of the command to restore the system to the default behavior.

tacacs-server last-resort {password | succeed}

no tacacs-server last-resort {password | succeed}

Syntax Description

password

Provide the user access to the privileged EXEC command mode by entering the password set by the enable command.

succeed

Provide the user access to the privileged EXEC command mode without further question.


Defaults

The last-resort feature is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use the tacacs-server last-resort command to be sure that you can log in; for example, a systems administrator would use this command to log in to troubleshoot TACACS servers that might be down.


Note This command is not used in authentication, authorization, and accounting (AAA) and TACACS+.


Examples

The following example shows how to force successful log in:

Switch(config)# tacacs-server last-resort succeed

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

enable password

Sets a local password to control access to various privilege levels.

login (EXEC)

Changes a login username.


tacacs-server login-timeout

Use the tacacs-server login-timeout global configuration command to cause the network access server to request the privileged password as verification for Terminal Access Controller Access Control System (TACACS) or Extended TACACS or to allow successful log in without further user input. Use the no form of the command to restore the system to the default behavior.

tacacs-server login-timeout {password | succeed}

no tacacs-server login-timeout {password | succeed}

Syntax Description

password

Provide the user access to the privileged EXEC command mode by entering the password set by the enable command.

succeed

Provide the user access to the privileged EXEC command mode without further question.


s

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Use the tacacs-server login-timeout command to be sure that you can log in; for example, a system administrator would use this command to log in to troubleshoot TACACS servers that might be down.


Note This command is not used in authentication, authorization, and accounting (AAA)/TACACS+.


Examples

The following example shows how to force successful log in:

Switch(config)# tacacs-server login-timeout succeed

Related Commands

Command
Description

enable password

Sets a local password to control access to various privilege levels.

login (EXEC)

Changes a login username.


tacacs-server optional-passwords

Use the tacacs-server optional-passwords global configuration command to specify that the first Terminal Access Controller Access Control System (TACACS) request to a TACACS or Extended TACACS server be made without password verification. Use the no form of this command to restore the default.

tacacs-server optional-passwords

no tacacs-server optional-passwords

Syntax Description

This command has no arguments or keywords.

Defaults

Password verification is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When the user enters the login name, the login request is transmitted with the name and a zero-length password. If accepted, the login procedure completes. If the TACACS server refuses this request, the server software prompts for a password and tries again when the user supplies a password. The TACACS server must support authentication for users without passwords to make use of this feature. This feature supports all TACACS request—login, Serial Line Internet Protocol (SLIP), enable, and so on.


Note This command is not used in authentication, authorization, and accounting (AAA)/TACACS+.


Examples

The following example shows how to configure the first login to bypass TACACS verification:

Switch(config)# tacacs-server optional-passwords

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

tacacs-server retransmit

Use the tacacs-server retransmit global configuration command to specify the number of times the Cisco IOS software searches the list of Terminal Access Controller Access Control System (TACACS) or Extended TACACS server hosts. Use the no form of this command to disable retransmission.

tacacs-server retransmit retries

no tacacs-server retransmit

Syntax Description

retries

Integer that specifies the retransmit count. The range is from 0 to 100.


Defaults

The default is two retries.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The Cisco IOS software tries all servers, allowing each one to time out before increasing the retransmit count.

Examples

The following example shows how to specify a retransmit counter value of 5:

Switch(config)# tacacs-server retransmit 5

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

tacacs-server timeout

Use the tacacs-server timeout global configuration command to set the interval that the server waits for a Terminal Access Controller Access Control System (TACACS), Extended TACACS, or TACACS+ server to reply. Use the no form of this command to restore the default.

tacacs-server timeout seconds

no tacacs-server timeout

Syntax Description

seconds

Integer that specifies the timeout interval in seconds. The range is from 1 to 1000.


Defaults

The timeout interval is 5 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Examples

The following example shows how to change the interval timer to 10 seconds:

Switch(config)# tacacs-server timeout 10

You can verify the previous command by entering the show running-config command in privileged EXEC mode.

Related Commands

Command
Description

tacacs-server host

Specifies a TACACS, Extended TACACS, or TACACS+ host.


udld

Use the udld interface configuration command to enable UniDirectional Link Detection (UDLD) on a port to assist with the detection of spanning-tree loops on logical one-way connections. Use the no form of this command to return the port setting to the global setting.

udld {enable | disable}

no udld {enable | disable}

Syntax Description

enable

Enable UDLD on the specified port.

disable

Disable UDLD on the specified port.


Defaults

UDLD follows the setting of the udld enable global configuration command and is disabled on all ports.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

UDLD is supported on fiber- and copper-based Ethernet ports.

A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of another switch.

This setting overrides the global UDLD configuration on the switch.

Examples

The following example shows how to enable UDLD on port 2:

Switch(config)# interface fastethernet 0/2
Switch(config-if)# udld enable

You can verify the previous command by entering the show running-config or the show udld interface command in privilege EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

show udld

Displays UDLD status for all ports or the specified port.

udld enable

Enables UDLD on all ports on the switch.

udld reset

Resets any interface that has been shut down by UDLD.


udld enable

Use the udld enable global configuration command to enable UniDirectional Link Detection (UDLD) on all ports on the switch to assist with the detection of spanning-tree loops on logical one-way connections. Use the no form of this command to return the switch setting to its default value.

udld enable

no udld enable

Syntax Description

This command has no keywords or arguments.

Defaults

UDLD is disabled on the switch.

Command Modes

Global configuration mode

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

UDLD is supported on fiber- and copper-based Ethernet ports.

A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of another switch.

This setting is overridden by each specific port UDLD configuration.

Examples

The following example shows how to enable UDLD on the switch:

Switch(config)# udld enable

You can verify the previous command by entering the show running-config in privilege EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

show udld

Displays UDLD status for all ports or the specified port.

udld

Enables UDLD on a port.

udld reset

Resets any interface that has been shut down by UDLD.


udld reset

Use the udld reset privileged EXEC command to reset all interfaces that have been shut down by UniDirectional Link Detection (UDLD).

udld reset

Syntax Description

This command has no keywords or arguments.

Command Modes

Privileged EXEC mode

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Examples

The following example shows how to reset all interfaces that have been shut down by UDLD:

Switch# udld reset
1 ports shutdown by UDLD were reset.

You can verify the previous command by entering the show udld in user EXEC mode.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch.

show udld

Displays UDLD status for all ports or the specified port.

udld

Enables UDLD on a port.

udld enable

Enables UDLD on all ports on the switch.


vlan

Use the vlan VLAN database command to configure VLAN characteristics. Use the no form of this command to delete a VLAN and its configured characteristics.

vlan vlan-id [name vlan-name] [media {ethernet | fddi | fdi-net | tokenring | tr-net}]
[state {suspend | active}] [said said-value] [mtu mtu-size] [ring ring-number]
[bridge bridge-number | type {srb | srt}] [parent parent-vlan-id]
[stp type {ieee | ibm | auto}] [are are-number] [ste ste-number]
[backupcrf {enable | disable}] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]

no vlan vlan-id [name vlan-name] [media {ethernet | fddi | fdi-net | tokenring | tr-net}]
[state {suspend | active}] [said said-value] [mtu mtu-size] [ring ring-number]
[bridge bridge-number | type {srb | srt}] [parent parent-vlan-id]
[stp type {ieee | ibm | auto}] [are are-number] [ste ste-number]
[backupcrf {enable | disable}] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]


Note Catalyst 2950 switches support only Ethernet ports. You can configure only FDDI and Token Ring media-specific characteristics for VLAN Trunk Protocol (VTP) global advertisements to other switches. These VLANs are locally suspended.


Table 2-6 lists the valid syntax for each media type.

Table 2-6 Valid Syntax for Different Media Types 

Media Type
Valid Syntax

Ethernet

vlan vlan-id [name vlan-name] media ethernet [state {suspend | active}]
[said said-value] [mtu mtu-size] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]

FDDI

vlan vlan-id [name vlan-name] media fddi [state {suspend | active}]
[said said-value] [mtu mtu-size] [ring ring-number] [parent parent-vlan-id] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]

FDDI-NET

vlan vlan-id [name vlan-name] media fdi-net [state {suspend | active}]
[said said-value] [mtu mtu-size] [bridge bridge-number]
[stp type {ieee | ibm | auto}] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]

If VTP V2 mode is disabled, do not set the stp type to auto.

Token Ring

VTP V2 mode is disabled.

vlan vlan-id [name vlan-name] media tokenring [state {suspend | active}]
[said said-value] [mtu mtu-size] [ring ring-number] [parent parent-vlan-id]
[tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]

Token Ring concentrator relay function (TRCRF)

VTP V2 mode is enabled.

vlan vlan-id [name vlan-name] media tokenring [state {suspend | active}]
[said said-value] [mtu mtu-size] [ring ring-number] [parent parent-vlan-id]
[bridge type {srb | srt}] [are are-number] [ste ste-number]
[backupcrf {enable | disable}] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]

Token Ring-NET

VTP V2 mode is disabled.

vlan vlan-id [name vlan-name] media tr-net [state {suspend | active}]
[said said-value] [mtu mtu-size] [bridge bridge-number]
[stp type {ieee | ibm}] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]

Token Ring bridge relay function (TRBRF)

VTP V2 mode is enabled.

vlan vlan-id [name vlan-name] media tr-net [state {suspend | active}]
[said said-value] [mtu mtu-size] [bridge bridge-number]
[stp type {ieee | ibm | auto}] [tb-vlan1 tb-vlan1-id] [tb-vlan2 tb-vlan2-id]


VLAN Configuration Rules

Table 2-7 describes the rules for configuring VLANs.

Table 2-7 VLAN Configuration Rules 

Configuration
Rule

VTP V2 mode is enabled, and you are configuring a TRCRF VLAN media type.

Specify a parent VLAN ID of a TRBRF that already exists in the database.

Specify a ring number. Do not leave this field blank.

Specify unique ring numbers when TRCRF VLANs have the same parent VLAN ID. Only one backup concentrator relay function (CRF) can be enabled.

VTP V2 mode is enabled, and you are configuring VLANs other than TRCRF media type.

Do not specify a backup CRF.

VTP V2 mode is enabled, and you are configuring a TRBRF VLAN media type.

Specify a bridge number. Do not leave this field blank.

VTP V2 mode is disabled.

No VLAN can have an STP type set to auto.

This rule applies to Ethernet, FDDI, FDDI-NET, Token Ring, and Token Ring-NET VLANs.

Add a VLAN that requires translational bridging (values are not set to zero).

The translational bridging VLAN IDs that are used must already exist in the database.

The translational bridging VLAN IDs that a configuration points to must also contain a pointer to the original VLAN in one of the translational bridging parameters (for example, Ethernet points to FDDI, and FDDI points to Ethernet).

The translational bridging VLAN IDs that a configuration points to must be different media types than the original VLAN (for example, Ethernet can point to Token Ring).

If both translational bridging VLAN IDs are configured, these VLANs must be different media types (for example, Ethernet can point to FDDI and Token Ring).


Syntax Description

vlan-id

ID of the configured VLAN. Valid IDs are from 1 to 1001 and must be unique within the administrative domain. Do not enter leading zeroes.

name

(Optional) Keyword to be followed by the VLAN name.

vlan-name

ASCII string from 1 to 32 characters that must be unique within the administrative domain.

media

(Optional) Keyword to be followed by the VLAN media type.

ethernet

Ethernet media type.

fddi

FDDI media type.

fdi-net

FDDI network entity title (NET) media type.

tokenring

Token Ring media type if the VTP V2 mode is disabled.

TRCRF media type if the VTP V2 mode is enabled.

tr-net

Token Ring network entity title (NET) media type if the VTP V2 mode is disabled.

TRBRF media type if the VTP V2 mode is enabled.

state

(Optional) Keyword to be followed by the VLAN state.

active

VLAN is operational.

suspend

VLAN is suspended. Suspended VLANs do not pass packets.

said

(Optional) Keyword to be followed by the security association identifier (SAID) as documented in IEEE 802.10.

said-value

Integer from 1 to 4294967294 that must be unique within the administrative domain.

mtu

(Optional) Keyword to be followed by the maximum transmission unit (packet size in bytes).

mtu-size

Packet size in bytes from 1500 to 18190 that the VLAN can use.

ring

(Optional) Keyword to be followed by the logical ring for an FDDI, Token Ring, or TRCRF VLAN.

ring-number

Integer from 1 to 4095.

bridge

(Optional) Keyword to be followed by the logical distributed source-routing bridge. This bridge that interconnects all logical rings having this VLAN as a parent VLAN in FDDI-NET, Token Ring-NET, and TRBRF VLANs.

bridge-number

Integer from 0 to 15.

type

Keyword to be followed by the bridge type. Applies only to TRCRF VLANs.

srb

Source-route bridging VLAN.

srt

Source-route transparent bridging VLAN.

parent

(Optional) Keyword to be followed by the parent VLAN of an existing FDDI, Token Ring, or TRCRF VLAN. This parameter identifies the TRBRF to which a TRCRF belongs and is required when defining a TRCRF.

parent-vlan-id

Integer 0 to 1001.

stp type

(Optional) Keyword to be followed by the spanning-tree type for FDDI-NET, Token Ring-NET, or TRBRF VLAN.

ieee

IEEE Ethernet STP running source-route transparent (SRT) bridging.

ibm

IBM STP running source-route bridging (SRB).

auto

STP running a combination of source-route transparent bridging (IEEE) and source-route bridging (IBM).

are

Keyword to be followed by the number of all-routes explorer (ARE) hops. This keyword applies only to TRCRF VLANs.

are-number

Integer from 0 to 13 that defines the maximum number of ARE hops for this VLAN.

ste

Keyword to be followed by the number of spanning-tree explorer (STE) hops. This keyword applies only to TRCRF VLANs.

ste-number

Integer from 0 to 13 that defines the maximum number of STE hops for this VLAN.

backupcrf

Keyword to be followed by the backup CRF mode. This keyword applies only to TRCRF VLANs.

enable

Enable backup CRF mode for this VLAN.

disable

Disable backup CRF mode for this VLAN.

tb-vlan1 and tb-vlan2

(Optional) Keyword to be followed by the first and second VLAN to which this VLAN is translationally bridged. Translational VLANs translate FDDI or Token Ring to Ethernet, for example.

tb-vlan1-id and tb-vlan2-id

Integer from 0 to 1001.


Defaults

The vlan-name variable is VLANxxxx, where xxxx represents four numeric digits (including leading zeroes) equal to the VLAN ID number.

The media type is ethernet.

The state is active.

The said value is 100000 plus the VLAN ID.

The mtu size for Ethernet, FDDI, and FDDI-NET VLANs is 1500 bytes. The MTU size for Token Ring and Token Ring-NET VLANs is 1500 bytes. The MTU size for TRBRF and TRCRF VLANs is 4472 bytes.

The ring number for Token Ring VLANs is zero. For FDDI VLANs, there is no default. For TRCRF VLANs, you must specify a ring number.

The bridge number is zero (no source-routing bridge) for FDDI-NET and Token Ring-NET VLANs. For TRBRF VLANs, you must specify a bridge number.

The parent VLAN ID is zero (no parent VLAN) for FDDI and Token Ring VLANs. For TRCRF VLANs, you must specify a parent VLAN ID. For both Token Ring and TRCRF VLANs, the parent VLAN ID must already exist in the database and be associated with a Token Ring-NET or TRBRF VLAN.

The STP type is ieee for FDDI-NET VLANs. For Token Ring-NET and TRBRF VLANs, the default is ibm.

The ARE value is 7.

The STE value is 7.

Backup CRF is disabled.

The tb-vlan1-id and tb-vlan2-id variables are zero (no translational bridging).

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

When the no vlan vlan-id form is used, the VLAN is deleted. Deleting VLANs automatically resets to zero any other parent VLANs and translational bridging parameters that refer to the deleted VLAN.

When the no vlan vlan-id name vlan-name form is used, the VLAN name returns to the default name (VLANxxxx, where xxxx represent four numeric digits (including leading zeroes) equal to the VLAN ID number).

When the no vlan vlan-id media form is used, the media type returns to the default (ethernet). Changing the VLAN media type (including the no form) resets the VLAN MTU to the default MTU for the type (unless the mtu keyword is also present in the command). It also resets the VLAN parent and translational bridging VLAN to the default (unless the parent, tb-vlan1, and/or tb-vlan2 are also present in the command).

When the no vlan vlan-id state form is used, the VLAN state returns to the default (active).

When the no vlan vlan-id said form is used, the VLAN SAID returns to the default (100,000 plus the VLAN ID).

When the no vlan vlan-id mtu form is used, the VLAN MTU returns to the default for the applicable VLAN media type. You can also modify the MTU using the media keyword.

When the no vlan vlan-id ring form is used, the VLAN logical ring number returns to the default (0).

When the no vlan vlan-id bridge form is used, the VLAN source-routing bridge number returns to the default (0). The vlan vlan-id bridge command is only used for FDDI-NET and Token Ring-NET VLANs and is ignored in other VLAN types.

When the no vlan vlan-id parent form is used, the parent VLAN returns to the default (0). The parent VLAN resets to the default if the parent VLAN is deleted or if the media keyword changes the VLAN type or the VLAN type of the parent VLAN.

When the no vlan vlan-id stp type form is used, the VLAN spanning-tree type returns to the default (ieee).

When the no vlan vlan-id tb-vlan1 or no vlan vlan-id tb-vlan2 form is used, the VLAN translational bridge VLAN (or VLANs, if applicable) returns to the default (0). Translational bridge VLANs must be a different VLAN type than the affected VLAN, and if two are specified, the two must be different VLAN types from each other. A translational bridge VLAN resets to the default if the translational bridge VLAN is deleted, if the media keyword changes the VLAN type, or if the media keyword changes the VLAN type of the corresponding translation bridge VLAN.

Examples

The following example shows how to add an Ethernet VLAN with default media characteristics. The default includes a vlan-name of VLANxxx, where xxxx represents four numeric digits (including leading zeroes) equal to the VLAN ID number. The default media option is ethernet; the state option is active. The default said-value variable is 100000 plus the VLAN ID; the mtu-size variable is 1500; the stp-type option is ieee. The VLAN is added if it did not already exist; otherwise, this command does nothing.

Switch(vlan)# vlan 2

The following example shows how to modify an existing VLAN by changing its name and MTU size:

Switch(vlan)# no vlan name engineering mtu 1200

You can verify the previous commands by entering the show vlan command in privileged EXEC mode.

Related Commands

Command
Description

show vlan

Displays the parameters for all configured VLANs or one VLAN (if the VLAN ID or name is specified) in the administrative domain.


vlan database

Use the vlan database privileged EXEC command to enter VLAN database mode from the command-line interface (CLI). From the CLI, you can add, delete, and modify VLAN configurations and globally propagate these changes by using the VLAN Trunk Protocol (VTP).

vlan database

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

To return to the privileged EXEC mode from the VLAN database mode, enter the exit command.


Note This command mode is different from other modes because it is session-oriented. When you add, delete, or modify VLAN parameters, the changes are not applied until you exit the session by entering the apply or exit commands. When the changes are applied, the VTP configuration version is incremented. You can also not apply the changes to the VTP database by entering abort.


Examples

The following example shows how to enter the VLAN database mode from the privileged EXEC mode:

Switch# vlan database
Switch(vlan)#

Related Commands

Command
Description

abort

Abandons the proposed new VLAN database, exits VLAN database mode, and returns to privileged EXEC mode.

apply

Implements the proposed new VLAN database, increments the database configuration revision number, propagates it throughout the administrative domain, and remains in VLAN database mode.

reset

Abandons the proposed VLAN database and remains in VLAN database mode. Resets the proposed database to the currently implemented VLAN database on the switch.

shutdown vlan

Shuts down (suspends) local traffic on the specified VLAN.


vtp

Use the vtp VLAN database command to configure the VLAN Trunk Protocol (VTP) mode. Use the no form of this command to return to the default setting.

vtp {server | client | transparent}

no vtp {server | client | transparent}

Syntax Description

server

Place the switch in VTP server mode. A switch in VTP server mode is enabled for VTP and sends advertisements. You can configure VLANs on it. The switch can recover all the VLAN information in the current VTP database from nonvolatile storage after reboot.

client

Place the switch in VTP client mode. A switch in VTP client mode is enabled for VTP, can send advertisements, but does not have enough nonvolatile storage to store VLAN configurations. You cannot configure VLANs on it. When a VTP client starts up, it does not transmit VTP advertisements until it receives advertisements to initialize its VLAN database.

transparent

Place the switch in VTP transparent mode. A switch in VTP transparent mode is disabled for VTP, does not transmit advertisements or learn from advertisements sent by other devices, and cannot affect VLAN configurations on other devices in the network. The switch receives VTP advertisements and forwards them on all trunk ports except the one on which the advertisement was received. The configuration of multi-VLAN ports causes the switch to automatically enter transparent mode.



Note The Catalyst 2950 switches support up to 64 VLANs.


Defaults

Server mode is the default mode.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The no vtp client and no vtp transparent forms of the command return the switch to VTP server mode.

The vtp server command is the same as no vtp client or no vtp transparent except that it does not return an error if the switch is not in client or transparent mode.

Examples

The following example shows how to place the switch in VTP transparent mode:

Switch(vlan)# vtp transparent

You can verify the previous commands by entering the show vtp status command in privileged EXEC mode.

Related Commands

Command
Description

show vtp status

Displays general information about the VTP management domain, status, and counters.


vtp domain

Use the vtp domain VLAN database command to configure the VLAN Trunk Protocol (VTP) administrative domain.

vtp domain domain-name

Syntax Description

domain-name

ASCII string from 1 to 32 characters that identifies the VTP administrative domain for the switch. The domain name is case sensitive.


Defaults

No domain name is defined.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

The switch is in the no-management-domain state until you configure a domain name. While in the no-management-domain state, the switch does not transmit any VTP advertisements even if changes occur to the local VLAN configuration. The switch leaves the no-management-domain state after receiving the first VTP summary packet on any port that is currently trunking or after configuring a domain name using the vtp domain command. If the switch receives its domain from a summary packet, it resets its configuration revision number to zero. After the switch leaves the no-management-domain state, it can never be configured to reenter it until you clear the nonvolatile RAM (NVRAM) and reload the software.

Domain names are case sensitive.

Once you configure a domain name, it cannot be removed. You can only reassign it to a different domain.

Examples

The following example shows how to set the administrative domain for the switch:

Switch(vlan)# vtp domain OurDomainName

You can verify the previous commands by entering the show vtp status command in privileged EXEC mode.

Related Commands

Command
Description

show vtp status

Displays general information about the VTP management domain, status, and counters.

vtp password

Configures the VTP administrative domain password.


vtp file

Use the vtp file global configuration command to modify the VLAN Trunk Protocol (VTP) configuration storage filename. Use the no form of this command to return the filename to its default name.

vtp file ifsfilename

no vtp file

Syntax Description

ifsfilename

The IOS IFS filename where the VTP VLAN configuration is stored.


Defaults

The default filename is flash:vlan.dat.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

This command cannot be used to load a new database; it only renames the file in which the existing database is stored.

Examples

The following example shows how to rename the filename for VTP configuration storage to vtpfilename:

Switch(config)# vtp file vtpfilename

Related Commands

Command
Description

vtp

Configures the VTP mode.


vtp password

Use the vtp password VLAN database command to configure the VLAN Trunk Protocol (VTP) administrative domain password. Use the no form of this command to remove the password.

vtp password password-value

no vtp password password-value

Syntax Description

password

Set the password for the generation of the 16-byte secret value used in MD5 digest calculation to be sent in VTP advertisements and to validate received VTP advertisements.

password-value

ASCII string from 8 to 64 characters. The password is case sensitive.


Defaults

No password is defined.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Passwords are case sensitive. Passwords should match on all switches in the same domain.

When the no vtp password form of the command is used, the switch returns to the no-password state.

Examples

The following example shows how to configure the VTP domain password:

Switch(vlan)# vtp password ThisIsOurDomain'sPassword

Related Commands

Command
Description

vtp domain

Configures the VTP administrative domain.


vtp v2-mode

Use the vtp v2-mode VLAN database command to enable VLAN Trunk Protocol (VTP) version 2 in the administrative domains. Use the no form of this command to disable V2 mode.

vtp v2-mode

no vtp v2-mode

Syntax Description

This command has no arguments or keywords.

Defaults

VTP version 2 is disabled.

Command Modes

VLAN database

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

Toggling the V2 mode state modifies certain parameters of certain default VLANs.

Each VTP switch automatically detects the capabilities of all the other VTP devices. To use V2 mode, all VTP switches in the network must support version 2; otherwise, you must configure them to operate in VTP version 1 mode (no vtp v2-mode).

If you are using VTP in a Token Ring environment, VTP V2 mode must be enabled.

If you are configuring a Token Ring bridge relay function (TRBRF) or Token Ring concentrator relay function (TRCRF) VLAN media type, you must use version 2.

If you are configuring a Token Ring or Token Ring-NET VLAN media type, you must use version 1.

Examples

The following example shows how to enable V2 mode in the proposed new VLAN database:

Switch(vlan)# vtp v2-mode

You can verify the previous commands by entering the show vtp status command in privileged EXEC mode.

Related Commands

Command
Description

show vtp status

Displays general information about the VTP management domain, status, and counters.

vtp

Configures the VTP mode.


wrr-queue bandwidth

Use the wrr-queue bandwidth global configuration command to assign weighted round-robin (WRR) weights to the four class of service (CoS) priority queues. Use the no form to disable the WRR scheduler and enable the strict priority scheduler.

wrr-queue bandwidth weight1...weight4

no wrr-queue bandwidth

Syntax Description

weight1...weight4

The ratio of weight1, weight2, weight3, and weight4 determines the weights of the WRR scheduler. Ranges are 1 to 255.


Defaults

WRR is disabled. The strict priority is the default scheduler.

Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

WRR allows bandwidth sharing at the egress port. This command defines the bandwidths for egress WRR through scheduling weights.

Examples

The following example shows how to assign WRR weights of 10, 20, 30, and 40 to the CoS priority queues 1, 2, 3 and 4:

Switch(config)# wrr-queue bandwidth 10 20 30 40 

The following example shows how to disable the WRR scheduler and enable the strict priority scheduler.

Switch(config)# no wrr-queue bandwidth

You can verify the previous command by entering the show wrr-queue bandwidth command in the privileged EXEC mode.

Related Commands

Command
Description

wrr-queue cos-map

Assigns CoS values to the CoS priority queues.

show wrr-queue bandwidth

Displays the WRR bandwidth allocation for the four CoS priority queues.

show wrr-queue cos-map

Displays the mapping of the CoS to the CoS priority queues.



wrr-queue cos-map

Use the wrr-queue cos-map global configuration command to assign class of service (CoS) values to the CoS priority queues. Use the no form set the CoS map to default setting.

wrr-queue cos-map quid cos1...cos 4

no wrr-queue cos-map

Syntax Description

quid

The queue id of the CoS priority queue. Ranges are 1 to 4 where 1 is the lowest CoS priority queue.

cos1...cosn

The CoS values that are mapped to the queue id.


Defaults

The default CoS values are as follows:

CoS Value
CoS Priority Queues

0, 1

1

2, 3

2

4, 5

3

6, 7

4


Command Modes

Global configuration

Command History

Release
Modification

12.0(5)WC(1)

This command was first introduced.


Usage Guidelines

CoS assigned at the ingress port is used to select a CoS priority at the egress port.

Examples

The following example shows how to map CoS values 0, 1 and 2 to CoS priority queue 1, value 3 to CoS priority queue 2, values 4 and 5 to CoS priority 3, and values 6 and 7 to CoS priority queue 4:

Switch(config)# wrr-queue cos-map 1 0 1 2
Switch(config)# wrr-queue cos-map 2 3
Switch(config)# wrr-queue cos-map 3 4 5
Switch(config)# wrr-queue cos-map 4 6 7

The following example shows how to map CoS values 0, 1, 2 and 3 to CoS priority queue 2.

Switch(config)# wrr-queue cos-map 2 0 1 2 3

If all other priority queues use their default setting, the new mapping is as follows:

CoS Value
CoS Priority Queue

Not applied

1

0, 1, 2, 3

2

4, 5

3

6, 7

4



Note CoS priority queue 1 is no longer used because no CoS value is assigned to the queue.


You can set the CoS values to the default values by entering the no wrr-queue bandwidth in the global configuration mode.

You can verify the previous command by entering the show wrr-queue cos-map command in the privileged EXEC mode.

Related Commands

Command
Description

wrr-queue bandwidth

Assigns weighted round-robin (WRR) weights to the four CoS priority queues.

show wrr-queue bandwidth

Displays the WRR bandwidth allocation for the four CoS priority queues.

show wrr-queue cos-map

Displays the mapping of the CoS to the priority queues.