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show mac-address-table multicast
show mac-address-table notification
spanning-tree extend system-id
spanning-tree loopguard default
spanning-tree mst configuration
spanning-tree mst forward-time
spanning-tree mst port-priority
spanning-tree portfast (global configuration)
spanning-tree portfast (interface configuration)
switchport port-security aging
2service-policy
Use the service-policy interface configuration command to apply a policy map defined by the policy-map command to the input of a particular interface. Use the no form of this command to remove the policy map and interface association.
service-policy input policy-map-name
no service-policy input policy-map-name
This command is available only if your switch is running the enhanced software image.
Syntax Description
Defaults
No policy maps are attached to the interface.
Command Modes
Interface configuration
Command History
Usage Guidelines
Only one policy map per ingress interface is supported.
Service policy maps cannot be defined on egress interfaces.
Note
For more information about configuring access control lists (ACLs), refer to the "Configuring Network Security with ACLs" chapter in the Catalyst 2950 Desktop Switch Software Configuration Guide for this release.
Examples
This example shows how to apply plcmap1 to an ingress interface:
Switch(config)# interface gigabitethernet0/1Switch(config-if)# service-policy input plcmap1You can verify your settings by entering the show policy-map privileged EXEC command.
Related Commands
Creates or modifies a policy map that can be attached to multiple interfaces to specify a service policy.
Displays quality of service (QoS) policy maps.
set
Use the set policy-map class configuration command to classify IP traffic by setting a Differentiated Services Code Point (DSCP) value. Use the no form of this command to remove traffic classification.
set ip dscp new-dscp
no set ip dscp new-dscp
This command is available only if your switch is running the enhanced software image.
Syntax Description
new-dscp
New DSCP value assigned to the classified traffic.
The supported DSCP values are 0, 8, 10, 16, 18, 24, 26, 32, 34, 40, 46, 48, and 56.
Defaults
No traffic classification is defined.
Command Modes
Policy-map class configuration
Command History
Usage Guidelines
The set command can be used in a policy with a match command.
The set command sets the DSCP value for in-profile packets.
Note
To return to policy-map configuration mode, use the exit command. To return to privileged EXEC mode, use the end command.
Note
Examples
This example shows how to assign a DSCP value of 10 to all FTP traffic without any policers:
Switch(config)# policy-map policy_ftpSwitch(config-pmap)# class ftp_classSwitch(config-pmap-c)# set ip dscp 10Switch(config-pmap)# exitYou can verify your settings by entering the show policy-map privileged EXEC command.
Related Commands
show access-lists
Use the show access-lists privileged EXEC command to display access control lists (ACLs) configured on the switch.
show access-lists [name | number] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show access-lists command:
Switch# show access-listsStandard IP access list testingaclpermit 10.10.10.2Standard IP access list wizard_1-1-1-2permit 1.1.1.2Extended IP access list 103permit tcp any any eq wwwExtended IP access list CMP-NAT-ACLDynamic Cluster-HSRP deny ip any anyDynamic Cluster-NAT permit ip any anypermit ip host 10.123.222.192 anypermit ip host 10.228.215.0 anypermit ip host 10.245.137.0 anypermit ip host 10.245.155.128 anypermit ip host 10.221.111.64 anypermit ip host 10.216.25.128 anypermit ip host 10.186.122.64 anypermit ip host 10.169.110.128 anypermit ip host 10.146.106.192 anyRelated Commands
show class-map
Use the show class-map user EXEC command to display quality of service (QoS) class maps, which define the match criteria to classify traffic.
show class-map [class-map-name] [ | {begin | exclude | include} expression]
This command is available only if your switch is running the enhanced software image.
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
If you do not specify a class-map-name, all class maps appear.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show class-map test command:
Switch> show class-map testClass Map match-all test (id 2)Match access-group name testingaclThis is an example of output from the show class-map command:
Switch> show class-mapClass Map match-all wizard_1-1-1-2 (id 3)Match access-group name videowizard_1-1-1-2Class Map match-all test (id 2)Match access-group name testingaclClass Map match-any class-default (id 0)Match anyClass Map match-all class1 (id 5)Match access-group 103Class Map match-all classtest (id 4)Description: This is a test.Match access-group name testingaclRelated Commands
Creates a class map to be used for matching packets to the class whose name you specify.
Defines the match criteria to classify traffic.
show cluster
Use the show cluster privileged 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
Command Modes
Privileged EXEC
Command History
Usage Guidelines
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 appears.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output when this command is entered on the active command switch:
Switch# show clusterCommand switch for cluster "Switch1"Total number of members: 7Status: 1 members are unreachableTime since last status change: 0 days, 0 hours, 2 minutesRedundancy: EnabledStandby command switch: Member 1Standby Group: Switch1_standbyStandby Group Number: 110Heartbeat interval: 8Heartbeat hold-time: 80Extended discovery hop count: 3This is an example of output when this command is entered on a member switch:
Switch# show clusterMember switch for cluster "commander"Member number: 3Management IP address: 192.192.192.192Command switch mac address: 0000.0c07.ac14Heartbeat interval: 8Heartbeat hold-time: 80This is an example of output when this command is entered on a member switch that is configured as the standby command switch:
Switch# show clusterMember switch for cluster "commander"Member number: 3 (Standby command switch)Management IP address: 192.192.192.192Command switch mac address: 0000.0c07.ac14Heartbeat interval: 8Heartbeat hold-time: 80This is an example of output when this command is entered on the command switch that has lost connectivity from member 1:
Switch# show clusterCommand switch for cluster "Switch1"Total number of members: 7Status: 1 members are unreachableTime since last status change: 0 days, 0 hours, 5 minutesRedundancy: DisabledHeartbeat interval: 8Heartbeat hold-time: 80Extended discovery hop count: 3This is an example of output when this command is entered on a member switch that has lost connectivity with the command switch:
Switch# show clusterMember switch for cluster "commander"Member number: <UNKNOWN>Management IP address: 192.192.192.192Command switch mac address: 0000.0c07.ac14Heartbeat interval: 8Heartbeat hold-time: 80Related Commands
show cluster candidates
Use the show cluster candidates privileged EXEC command on the command switch to display a list of candidate switches.
show cluster candidates [detail | mac-address H.H.H.] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
You should only enter this command 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 output means switch member number. If E is in the SN column, it means that the switch is discovered through extended discovery. If E does not appear in the SN column, it means that the switch member number is the upstream neighbor of the candidate switch. 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 do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show cluster candidates command:
Switch# show cluster candidates|---Upstream---|MAC Address Name Device Type PortIf FEC Hops SN PortIf FEC00d0.7961.c4c0 c2950-012 WS-C2950-12 Fa0/5 1 0 Fa0/300d0.bbf5.e900 ldf-dist-128 WS-C3524-XL Fa0/7 1 0 Fa0/2400e0.1e7e.be80 1900_Switch 1900 3 0 1 0 Fa0/1100e0.1e9f.7a00 c2924XL-24 WS-C2924-XL Fa0/5 1 0 Fa0/300e0.1e9f.8c00 c2912XL-12-2 WS-C2912-XL Fa0/4 1 0 Fa0/700e0.1e9f.8c40 c2912XL-12-1 WS-C2912-XL Fa0/1 1 0 Fa0/90050.2e4a.9fb0 C3508XL-0032 WS-C3508-XL E0050.354e.7cd0 C2924XL-0034 WS-C2924-XL EThis is an example of 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.c4c0Device 'c2950-12' with mac address number 00d0.7961.c4c0Device type: cisco WS-C2950-12Upstream MAC address: 00d0.796d.2f00 (Cluster Member 0)Local port: Fa0/3 FEC number:Upstream port: Fa0/13 FEC Number:Hops from cluster edge: 1Hops from command device: 1This is an example of 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 0010.7bb6.1cc0Device 'c2950-24' with mac address number 0010.7bb6.1cc0Device type: cisco WS-C2950-24Upstream MAC address: 0010.7bb6.1cd4Local port: Fa2/1 FEC number:Upstream port: Fa0/24 FEC Number:Hops from cluster edge: 3Hops from command device: -This is an example of output from the show cluster candidates detail command:
Switch# show cluster candidates detailDevice 'c2950-12' with mac address number 00d0.7961.c4c0Device type: cisco WS-C2950-12Upstream MAC address: 00d0.796d.2f00 (Cluster Member 1)Local port: Fa0/3 FEC number:Upstream port: Fa0/13 FEC Number:Hops from cluster edge: 1Hops from command device: 2Device '1900_Switch' with mac address number 00e0.1e7e.be80Device type: cisco 1900Upstream MAC address: 00d0.796d.2f00 (Cluster Member 2)Local port: 3 FEC number: 0Upstream port: Fa0/11 FEC Number:Hops from cluster edge: 1Hops from command device: 2Device 'c2924-XL' with mac address number 00e0.1e9f.7a00Device type: cisco WS-C2924-XLUpstream MAC address: 00d0.796d.2f00 (Cluster Member 3)Local port: Fa0/5 FEC number:Upstream port: Fa0/3 FEC Number:Hops from cluster edge: 1Hops from command device: 2Related Commands
Displays the cluster status and a summary of the cluster to which the switch belongs.
Displays information about the cluster members.
show cluster members
Use the show cluster members privileged EXEC command on the command switch to display information about the cluster members.
show cluster members [n | detail] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
You should only enter this command 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 do not appear, but the lines that contain Output appear.
Examples
This is an example of 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 State0 0002.4b29.2e00 StLouis1 0 Up (Cmdr)1 0030.946c.d740 tal-switch-1 Fa0/13 1 0 Gi0/1 Up2 0002.b922.7180 nms-2820 10 0 2 1 Fa0/18 Up3 0002.4b29.4400 SanJuan2 Gi0/1 2 1 Fa0/11 Up4 0002.4b28.c480 GenieTest Gi0/2 2 1 Fa0/9 UpThis is an example of output from the show cluster members 3 command for cluster member 3:
Switch# show cluster members 3Device 'SanJuan2' with member number 3Device type: cisco WS-C3550-12TMAC address: 0002.4b29.4400Upstream MAC address: 0030.946c.d740 (Cluster member 1)Local port: Gi0/1 FEC number:Upstream port: Fa0/11 FEC Number:Hops from command device: 2This is an example of output from the show cluster members detail command:
Switch# show cluster members detailDevice 'StLouis1' with member number 0 (Command Switch)Device type: cisco WS-C3550-12TMAC address: 0002.4b29.2e00Upstream MAC address:Local port: FEC number:Upstream port: FEC Number:Hops from command device: 0Device 'tal-switch-14' with member number 1Device type: cisco WS-C3548-XLMAC address: 0030.946c.d740Upstream MAC address: 0002.4b29.2e00 (Cluster member 0)Local port: Fa0/13 FEC number:Upstream port: Gi0/1 FEC Number:Hops from command device: 1Device 'nms-2820' with member number 2Device type: cisco 2820MAC address: 0002.b922.7180Upstream MAC address: 0030.946c.d740 (Cluster member 1)Local port: 10 FEC number: 0Upstream port: Fa0/18 FEC Number:Hops from command device: 2Device 'SanJuan2' with member number 3Device type: cisco WS-C3550-12TMAC address: 0002.4b29.4400Upstream MAC address: 0030.946c.d740 (Cluster member 1)Local port: Gi0/1 FEC number:Upstream port: Fa0/11 FEC Number:Hops from command device: 2Device 'Test' with member number 4Device type: cisco SeaHorseMAC address: 0002.4b28.c480Upstream MAC address: 0030.946c.d740 (Cluster member 1)Local port: Gi0/2 FEC number:Upstream port: Fa0/9 FEC Number:Hops from command device: 2Device 'Palpatine' with member number 5Device type: cisco WS-C2924M-XLMAC address: 00b0.6404.f8c0Upstream MAC address: 0002.4b29.2e00 (Cluster member 0)Local port: Gi2/1 FEC number:Upstream port: Gi0/7 FEC Number:Hops from command device: 1Related Commands
Displays the cluster status and a summary of the cluster to which the switch belongs.
Displays a list of candidate switches.
show dot1x
Use the show dot1x privileged EXEC command to display the 802.1X statistics, administrative status, and operational status for the switch or for the specified interface.
show dot1x [interface interface-id] | [statistics [interface interface-id]] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
If you do not specify an interface, global parameters and a summary appear. If you specify an interface, details for that interface appear.
If you specify the statistics keyword without the interface interface-id option, statistics appear for all interfaces. If you specify the statistics keyword with the interface interface-id option, statistics appear for the specified interface.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show dot1x command:
Switch# show dot1xGlobal 802.1X Parametersreauth-enabled noreauth-period 3600quiet-period 60tx-period 30supp-timeout 30server-timeout 30reauth-max 2max-req 2802.1X Port SummaryPort Name Status Mode AuthorizedGi0/1 disabled n/a n/aGi0/2 enabled Auto (negotiate) no802.1X Port Details802.1X is disabled on GigabitEthernet0/1802.1X is enabled on GigabitEthernet0/2Status UnauthorizedPort-control AutoSupplicant 0060.b0f8.fbfbMultiple Hosts DisallowedCurrent Identifier 2Authenticator State MachineState AUTHENTICATINGReauth Count 1Backend State MachineState RESPONSERequest Count 0Identifier (Server) 2Reauthentication State MachineState INITIALIZE
Note
In the 802.1X Port Summary section of the example, the Status column shows whether the port is enabled for 802.1X (the dot1x port-control interface configuration command is set to auto or force-unauthorized). The Mode column shows the operational status of the port; for example, if you configure the dot1x port-control interface configuration command to force-unauthorized, but the port has not transitioned to that state, the Mode column displays auto. If you disable 802.1X, the Mode column displays n/a.
The Authorized column shows the authorization state of the port. For information about port states, refer to the "Configuring 802.1X Port-Based Authentication" chapter in the Catalyst 2950 Desktop Switch Software Configuration Guide.
This is an example of output from the show dot1x interface gigabitethernet0/2 privileged EXEC command. Table 2-4 describes the fields in the example.
Switch# show dot1x interface gigabitethernet0/2802.1X is enabled on GigabitEthernet0/2Status AuthorizedPort-control AutoSupplicant 0060.b0f8.fbfbMultiple Hosts DisallowedCurrent Identifier 3Authenticator State MachineState AUTHENTICATEDReauth Count 0Backend State MachineState IDLERequest Count 0Identifier (Server) 2Reauthentication State MachineState INITIALIZE
Table 2-4 show dot1x interface Field Description
802.1X is enabled on GigabitEthernet0/2
Status
Status of the port (authorized or unauthorized). The status of a port appears as authorized if the dot1x port-control interface configuration command is set to auto, and authentication was successful.
Port-control
Setting of the dot1x port-control interface configuration command.
Supplicant
Ethernet MAC address of the client, if one exists. If the switch has not discovered the client, this field displays Not set.
Multiple Hosts
Setting of the dot1x multiple-hosts interface configuration command (allowed or disallowed).
Current Identifier1
Each exchange between the switch and the client includes an identifier, which matches requests with responses. This number is incremented with each exchange and can be reset by the authentication server.
1 This field and the remaining fields in the example show internal state information. For a detailed description of these state machines and their settings, refer to the IEEE 802.1X standard.
This is an example of output from the show dot1x statistics interface gigiabitethernet0/1 command. Table 2-5 describes the fields in the example.
Switch# show dot1x statistics interface gigabitethernet0/1GigabitEthernet0/1Rx: EAPOL EAPOL EAPOL EAPOL EAP EAP EAPStart Logoff Invalid Total Resp/Id Resp/Oth LenError0 0 0 21 0 0 0Last LastEAPOLVer EAPOLSrc1 0002.4b29.2a03Tx: EAPOL EAP EAPTotal Req/Id Req/Oth622 445 0
Table 2-5 show dot1x statistics Field Descriptions
RX EAPOL1 Start
Number of valid EAPOL-start frames that have been received
RX EAPOL Logoff
Number of EAPOL-logoff frames that have been received
RX EAPOL Invalid
Number of EAPOL frames that have been received and have an unrecognized frame type
RX EAPOL Total
Number of valid EAPOL frames of any type that have been received
RX EAP2 Resp/ID
Number of EAP-response/identity frames that have been received
RX EAP Resp/Oth
Number of valid EAP-response frames (other than response/identity frames) that have been received
RX EAP LenError
Number of EAPOL frames that have been received in which the packet body length field is invalid
Last EAPOLVer
Protocol version number carried in the most recently received EAPOL frame
LAST EAPOLSrc
Source MAC address carried in the most recently received EAPOL frame
TX EAPOL Total
Number of EAPOL frames of any type that have been sent
TX EAP Req/Id
Number of EAP-request/identity frames that have been sent
TX EAP Req/Oth
Number of EAP-request frames (other than request/identity frames) that have been sent
1 EAPOL = Extensible Authentication Protocol over LAN
2 EAP = Extensible Authentication Protocol
Related Commands
show env
Use the show env user EXEC command to display fan information for the switch.
show env {all | fan} [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show env all command:
Switch> show env allFAN 1 is OKThis is an example of output from the show env fan command:
Switch# show env fanFAN 1 is FAULTYshow errdisable recovery
Use the show errdisable recovery user EXEC command to display the error-disable recovery timer information.
show errdisable recovery [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show errdisable recovery command:
Switch> show errdisable recoveryErrDisable Reason Timer Status----------------- --------------udld Enabledbpduguard Enabledchannel-misconfig Enabledpagp-flap Enableddtp-flap Enabledlink-flap Enabledpsecure-violation Enabledgbic-invalid EnabledTimer interval:300 secondsInterfaces that will be enabled at the next timeout:Interface Errdisable reason Time left(sec)--------- ----------------- --------------Gi0/4 link-flap 279Related Commands
Configures the recover mechanism variables.
show interfaces trunk
Displays interface status or a list of interfaces in error-disabled state.
show etherchannel
Use the show etherchannel user EXEC command to display EtherChannel information for a channel.
show etherchannel [channel-group-number] {brief | detail | load-balance | port | port-channel | summary} [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
12.1(6)EA2
This command was first introduced. It replaced the show port group command.
Usage Guidelines
If you do not specify a channel-group, all channel groups appear.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show etherchannel 1 detail command:
Switch> show etherchannel 1 detailGroup state = L2Ports: 1 Maxports = 8Port-channels: 1 Max Port-channels = 1Ports in the group:-------------------Port: Fa0/3------------Port state = Down Not-in-BndlChannel group = 1 Mode = Automatic-Sl Gcchange = 0Port-channel = null GC = 0x00000000 Pseudo port-channel = Po1Port index = 0 Load = 0x00Flags: S - Device is sending Slow hello. C - Device is in Consistent state.A - Device is in Auto mode. P - Device learns on physical port.d - PAgP is down.Timers: H - Hello timer is running. Q - Quit timer is running.S - Switching timer is running. I - Interface timer is running.Local information:Hello Partner PAgP Learning GroupPort Flags State Timers Interval Count Priority Method IfindexFa0/3 dA U1/S1 1s 0 200 Any 0Age of the port in the current state: 10d:23h:07m:37sPort-channels in the group:----------------------Port-channel: Po1------------Age of the Port-channel = 03d:02h:22m:43sLogical slot/port = 1/0 Number of ports = 0GC = 0x00000000 HotStandBy port = nullPort state = Port-channel Ag-Not-InuseThis is an example of output from the show etherchannel 1 summary command:
Switch> show etherchannel 1 summaryFlags: D - down P - in port-channelI - stand-alone s - suspendedR - Layer3 S - Layer2U - port-channel in useGroup Port-channel Ports-----+------------+-----------------------------------------------------------1 Po1(SD) Fa0/3(D)This is an example of output from the show etherchannel 1 brief command:
Switch> show etherchannel 1 briefGroup state = L2Ports: 1 Maxports = 8Port-channels: 1 Max Port-channels = 1This is an example of output from the show etherchannel 1 port command:
Switch> show etherchannel 1 portPorts in the group:-------------------Port: Fa0/3------------Port state = Down Not-in-BndlChannel group = 1 Mode = Automatic-Sl Gcchange = 0Port-channel = null GC = 0x00000000 Pseudo port-channel = Po1Port index = 0 Load = 0x00Flags: S - Device is sending Slow hello. C - Device is in Consistent state.A - Device is in Auto mode. P - Device learns on physical port.d - PAgP is down.Timers: H - Hello timer is running. Q - Quit timer is running.S - Switching timer is running. I - Interface timer is running.Local information:Hello Partner PAgP Learning GroupPort Flags State Timers Interval Count Priority Method IfindexFa0/3 dA U1/S1 1s 0 200 Any 0Age of the port in the current state: 10d:23h:13m:21sRelated Commands
Assigns an Ethernet interface to an EtherChannel group.
Accesses or creates the port channel.
show file
Use the show file privileged EXEC command to display a list of open file descriptors, file information, and file system information.
show file {descriptors | information {device:}filename | systems} [ | {begin | exclude |
include} expression]Syntax Description
Command Modes
Privileged EXEC
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(6)EA2
The descriptors and information keywords were added.
Usage Guidelines
File descriptors are the internal representations of open files. You can use this command to see if another user has a file open.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show file descriptors command:
Switch# show file descriptorsFile Descriptors:FD Position Open PID Path0 187392 0001 2 tftp://temp/hampton/c2950g.a1 184320 030A 2 flash:c2950-i-m.aTable 2-6 describes the fields in the show file descriptors command output.
This is an example of output from the show file information nvram:startup-config command:
Switch# show file information nvram:startup-confignvram:startup-config:type is ascii textTable 2-7 lists the possible file types for the previous example.
This is an example of output from the show file systems command:
Switch# show file systemsFile Systems:Size(b) Free(b) Type Flags Prefixes* 7741440 433152 flash rw flash:7741440 433152 unknown rw zflash:32768 25316 nvram rw nvram:- - network rw tftp:- - opaque rw null:- - opaque rw system:- - opaque ro xmodem:- - opaque ro ymodem:- - network rw rcp:- - network rw ftp:For this example, Table 2-8 describes the fields in the show file systems command output. Table 2-9 lists the file system types. Table 2-10 lists the file system flags.
Table 2-10 File System Flags
ro
The file system is Read Only.
wo
The file system is Write Only
rw
The file system is Read/Write.
show interfaces
Use the show interfaces privileged EXEC command to display the administrative and operational status of all interfaces or a specified interface.
show interfaces [interface-id | vlan vlan-id] [accounting | description | etherchannel | pruning | stats | status [err-disabled] | switchport | trunk] [ | {begin | exclude | include} expression]
Syntax Description
Note
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show interfaces accounting command:
Switch# show interfaces accountingVlan1Protocol Pkts In Chars In Pkts Out Chars OutIP 17950 2351279 3205 411175ARP 8626 552064 62 3720Interface Vlan5 is disabledFastEthernet0/1Protocol Pkts In Chars In Pkts Out Chars OutSpanning Tree 2956958 179218508 34383 2131700CDP 14301 5777240 14307 5722418VTP 0 0 1408 145908DTP 28592 1572560 0 0<output truncated>This is an example of output from the show interfaces gigabitethernet0/1 command:
Switch# show interfaces gigabitethernet0/1FastEthernet0/1 is up, line protocol is downHardware is Fast Ethernet, address is 0005.7428.09c1 (bia 0005.7428.09c1)MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,reliability 255/255, txload 1/255, rxload 1/255Encapsulation ARPA, loopback not setKeepalive set (10 sec)Auto-duplex, Auto-speedinput flow-control is off, output flow-control is offLast input never, output 4d21h, output hang neverLast clearing of "show interface" counters neverInput queue:0/75/0/0 (size/max/drops/flushes); Total output drops:0Queueing strategy:fifoOutput queue :0/40 (size/max)5 minute input rate 0 bits/sec, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec1 packets input, 64 bytes, 0 no bufferReceived 0 broadcasts, 0 runts, 0 giants, 0 throttles0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored0 watchdog, 0 multicast, 0 pause input0 input packets with dribble condition detected1 packets output, 64 bytes, 0 underruns0 output errors, 0 collisions, 2 interface resets0 babbles, 0 late collision, 0 deferred0 lost carrier, 0 no carrier, 0 PAUSE output0 output buffer failures, 0 output buffers swapped outThis is an example of output from the show interfaces gigabitethernet0/2 description command when the interface has been described as Connects to Marketing by using the description interface configuration command.
Switch# show interfaces gigabitethernet0/2 descriptionInterface Status Protocol DescriptionG10/2 up down Connects to MarketingThis is an example of output from the show interfaces fastethernet0/1 pruning command when pruning is enabled in the VTP domain:
Switch# show interfaces fastethernet0/1 pruningPort Vlans pruned for lack of request by neighborFa0/1 4,196Port Vlan traffic requested of neighborFa0/1 1,4This is an example of output from the show interfaces stats command:
Switch# show interfaces statsVlan1Switching path Pkts In Chars In Pkts Out Chars OutProcessor 3224706 223689126 3277307 280637322Route cache 0 0 0 0Total 3224706 223689126 3277307 280637322Interface Vlan5 is disabledFastEthernet0/1Switching path Pkts In Chars In Pkts Out Chars OutProcessor 3286423 231672787 179501 17431060Route cache 0 0 0 0Total 3286423 231672787 179501 17431060This is an example of output from the show interfaces status command. It displays the status of all interfaces.
Switch# show interfaces statusPort Name Status Vlan Duplex Speed TypeFa0/1 notconnect 1 auto auto 10/100BaseTXFa0/2 notconnect 1 auto auto 10/100BaseTXFa0/3 disabled 100 auto auto 10/100BaseTXFa0/4 connected trunk a-full a-100 10/100BaseTXFa0/5 notconnect 1 auto auto 10/100BaseTXFa0/6 connected trunk a-full a-100 10/100BaseTXFa0/7 notconnect 1 auto auto 10/100BaseTXFa0/8 connected 1 a-full a-100 10/100BaseTXFa0/9 disabled 1 auto auto 10/100BaseTXFa0/10 notconnect 5 auto 100 10/100BaseTXFa0/11 disabled 1 auto auto 10/100BaseTXFa0/12 disabled 1 auto auto 10/100BaseTXGi0/1 disabled 1 auto auto unknownGi0/2 notconnect 1 auto auto unknownPo1 notconnect 1 auto autoThis is an example of output from the show interfaces status err-disabled command. It displays the status of interfaces in error-disabled state.
switch#show interfaces fa0/15 status err-disabledPort Name Status ReasonFa0/15 err-disabled psecure-violationThis is an example of output from the show interfaces etherchannel command when port channels are configured on the switch:
Switch# show interfaces etherchannel----FastEthernet0/1:Port state = Up Mstr In-BndlChannel group = 1 Mode = On/FEC Gcchange = 0Port-channel = Po1 GC = 0x00010001 Pseudo port-channel = Po1Port index = 0 Load = 0x00Age of the port in the current state:00d:00h:06m:54s----Port-channel1:Age of the Port-channel = 09d:22h:45m:14sLogical slot/port = 1/0 Number of ports = 1GC = 0x00010001 HotStandBy port = nullPort state = Port-channel Ag-InusePorts in the Port-channel:Index Load Port EC state------+------+------+------------0 00 Fa0/1 onTime since last port bundled: 00d:00h:06m:54s Fa0/1This is an example of output from the show interfaces switchport command for a single interface. Table 2-11 describes the fields in the output.
Switch# show interfaces gigabitethernet0/1 switchportName:Fa0/1Switchport:EnabledAdministrative Mode:static accessOperational Mode:downAdministrative Trunking Encapsulation:dot1qNegotiation of Trunking:OffAccess Mode VLAN:1 (default)Trunking Native Mode VLAN:1 (default)Trunking VLANs Enabled:ALLPruning VLANs Enabled:2-1001Protected:falseVoice VLAN:dot1p (Inactive)Appliance trust:5
This is an example of output from the show interfaces trunk command:
Switch# show interfaces trunkPort Mode Encapsulation Status Native vlanFa0/4 on 802.1q trunking 1Fa0/6 on 802.1q trunking 1Port Vlans allowed on trunkFa0/4 1-4094Fa0/6 1-4094Port Vlans allowed and active in management domainFa0/4 1-2,51-52Fa0/6 1-2,51-52Port Vlans in spanning tree forwarding state and not prunedFa0/4 1Fa0/6 1-2,51-52This is an example of output from the show interfaces fastethernet0/1 trunk command. It displays trunking information for the interface.
Switch# show interfaces fastethernet0/1 trunkPort Mode Encapsulation Status Native vlanFa0/1 desirable 802.1q trunking 1Port Vlans allowed on trunkFa0/1 1-4094Port Vlans allowed and active in management domainFa0/1 1,4,196,306Port Vlans in spanning tree forwarding state and not prunedFa0/1 1,306Related Commands
Configures a port as a static-access or dynamic-access port.
Isolates unicast, multicast, and broadcast traffic at Layer 2 from other protected ports on the same switch.
switchport trunk pruning
Configures the VLAN pruning-eligible list for ports in trunking mode.
show interfaces counters
Use the show interfaces counters privileged EXEC command to display various counters for a specific interface or for all interfaces.
show interfaces [interface-id | vlan vlan-id] counters [broadcast | errors | multicast | trunk | unicast] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
If you do not enter any keywords, all counters for all interfaces are included.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show interfaces counters command. It displays all the counters for the switch.
Switch# show interfaces countersPort InOctets InUcastPkts InMcastPkts InBcastPktsGi0/1 23324617 10376 185709 126020Gi0/2 0 0 0 0Port OutOctets OutUcastPkts OutMcastPkts OutBcastPktsGi0/1 4990607 28079 21122 10Gi0/2 1621568 25337 0 0This is an example of output from the show interfaces counters broadcast command. It displays the dropped broadcast traffic for all interfaces.
Switch# show interfaces counters broadcastPort BcastSuppDiscardsGi0/1 1Gi0/2 0This is an example of output from the show interfaces gigabitethernet0/1 counters broadcast command. It displays the dropped broadcast traffic for an interface.
Switch# show interfaces gigabitethernet0/1 counters broadcastPort BcastSuppDiscardsGi0/1 0This is an example of output from the show interfaces counters errors command. It displays the interface error counters for all interfaces.
Switch# show interfaces counters errorsPort Align-Err FCS-Err Xmit-Err Rcv-Err UnderSizeGi0/1 0 0 0 0 0Gi0/2 0 0 0 0 0Port Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts GiantsGi0/1 0 0 0 0 0 0 0Gi0/2 0 0 0 0 0 0 0This is an example of output from the show interfaces counters multicast command. It displays the dropped multicast traffic for all interfaces.
Switch# show interfaces counters multicastPort McastSuppDiscardsGi0/1 0Gi0/2 0This is an example of output from the show interfaces counters trunk command. It displays the trunk counters for all interfaces.
Switch# show interfaces counters trunkPort TrunkFramesTx TrunkFramesRx WrongEncapGi0/1 0 0 0Gi0/2 0 0 0This is an example of output from the show interfaces counters unicast command. It displays the dropped unicast traffic for all interfaces.
Switch# show interfaces counters unicastPort UcastSuppDiscardsGi0/1 6872Gi0/2 0Related Commands
Displays interface characteristics.
Configures broadcast, multicast, and unicast storm control for an interface.
show ip access-lists
Use the show ip access-lists privileged EXEC command to display IP access control lists (ACLs) configured on the switch.
show ip access-lists [name | number] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show ip access-lists command:
Switch# show ip access-listsStandard IP access list testingaclpermit 10.10.10.2Standard IP access list wizard_1-1-1-2permit 1.1.1.2Extended IP access list 103permit tcp any any eq wwwExtended IP access list CMP-NAT-ACLDynamic Cluster-HSRP deny ip any anyDynamic Cluster-NAT permit ip any anypermit ip host 10.245.155.128 anypermit ip host 10.245.137.0 anypermit ip host 10.146.106.192 anypermit ip host 10.216.25.128 anypermit ip host 10.228.215.0 anypermit ip host 10.221.111.64 anypermit ip host 10.123.222.192 anypermit ip host 10.169.110.128 anypermit ip host 10.186.122.64 anyThis is an example of output from the show ip access-lists 103 command:
Switch# show ip access-lists 103Extended IP access list 103permit tcp any any eq wwwRelated Commands
Configures an extended IP ACL on the switch.
Configures a standard IP ACL on the switch.
Configures an IP ACL on the switch.
Displays ACLs configured on a switch.
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 [vlan vlan-id] [ | {begin | exclude | include} expression]
show ip igmp snooping [vlan vlan-id] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
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 do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show ip igmp snooping command:
Switch# show ip igmp snoopingvlan 1----------IGMP snooping is globally enabledIGMP snooping is enabled on this VlanIGMP snooping immediate-leave is enabled on this VlanIGMP snooping mrouter learn mode is pim-dvmrp on this Vlanvlan 2----------IGMP snooping is globally enabledIGMP snooping is enabled on this VlanIGMP snooping immediate-leave is enabled on this VlanIGMP snooping mrouter learn mode is cgmp on this Vlanvlan 3----------IGMP snooping is globally enabledIGMP snooping is enabled on this VlanIGMP snooping immediate-leave is disabled on this VlanIGMP snooping mrouter learn mode is cgmp on this Vlanvlan 4----------IGMP snooping is globally enabledIGMP snooping is enabled on this VlanIGMP snooping immediate-leave is disabled on this VlanIGMP snooping mrouter learn mode is cgmp on this Vlanvlan 5----------IGMP snooping is globally enabledIGMP snooping is enabled on this VlanIGMP snooping immediate-leave is disabled on this VlanIGMP snooping mrouter learn mode is pim-dvmrp on this Vlanvlan 33----------IGMP snooping is globally enabledIGMP snooping is enabled on this VlanIGMP snooping immediate-leave is disabled on this VlanIGMP snooping mrouter learn mode is pim-dvmrp on this VlanThis is an example of output from the show ip igmp snooping vlan 1 command:
Switch# show ip igmp snooping vlan 1vlan 1----------IGMP snooping is globally enabledIGMP snooping is enabled on this VlanIGMP snooping immediate-leave is enabled on this VlanIGMP snooping mrouter learn mode is pim-dvmrp on this VlanRelated Commands
Enables IGMP snooping.
ip igmp snooping vlan vlan-id
Enables IGMP snooping on the VLAN interface.
Configures IGMP Immediate-Leave processing.
Configures a Layer 2 port as a multicast router port.
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
Command Modes
Privileged EXEC
Command History
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 do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show ip igmp snooping mrouter vlan 1 command:
Note
Switch# show ip igmp snooping mrouter vlan 1Vlan ports---- -----1 Fa0/2(static), Fa0/3(dynamic)Related Commands
show mac access-group
Use the show mac access-group user EXEC command to display the MAC access control lists (ACLs) configured for an interface or a switch.
show mac access-group [interface interface-id] [ | {begin | exclude | include} expression]
This command is available only if your switch is running the enhanced software image.
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
Use the show mac access-group command without keywords to display MAC ACLs for all interfaces.
Use this command with the interface keyword to display ACLs for a specific interface.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mac access-group command:
Switch> show mac access-groupInterface FastEthernet0/1:Inbound access-list is not setInterface FastEthernet0/2:Inbound access-list is not setInterface FastEthernet0/3:Inbound access-list is not setInterface FastEthernet0/4:Inbound access-list is not set...Interface FastEthernet0/47:Inbound access-list is not setInterface FastEthernet0/48:Inbound access-list is not setInterface GigabitEthernet0/1:Inbound access-list is not setInterface GigabitEthernet0/2:Inbound access-list is 101This is an example of output from the show mac access-group interface gigabitethernet 0/2 command:
Switch# show mac access-group interface gigabitethernet 0/2Interface GigabitEthernet0/2:Inbound access-list is 101Related Commands
show mac-address-table
Use the show mac-address-table user EXEC command to display the MAC address table.
show mac-address-table [aging-time | count | dynamic | static] [address hw-addr]
[interface interface-id] [vlan vlan-id] [ | {begin | exclude | include} expression]Syntax Description
Command Modes
User EXEC
Command History
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 appear.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mac-address-table command:
Switch> show mac-address-tableDynamic Addresses Count: 9Secure Addresses (User-defined) Count: 0Static Addresses (User-defined) Count: 0System Self Addresses Count: 41Total MAC addresses: 50Non-static Address Table:Destination Address Address Type VLAN Destination Port------------------- ------------ ---- --------------------0010.0de0.e289 Dynamic 1 FastEthernet0/10010.7b00.1540 Dynamic 2 FastEthernet0/50010.7b00.1545 Dynamic 2 FastEthernet0/50060.5cf4.0076 Dynamic 1 FastEthernet0/10060.5cf4.0077 Dynamic 1 FastEthernet0/10060.5cf4.1315 Dynamic 1 FastEthernet0/10060.70cb.f301 Dynamic 1 FastEthernet0/100e0.1e42.9978 Dynamic 1 FastEthernet0/100e0.1e9f.3900 Dynamic 1 FastEthernet0/1This is an example of output from the show mac-address-table static interface fastethernet0/2 vlan 1 command:
Switch> show mac-address-table static interface fastethernet0/2 vlan 1vlan mac address type ports-----+---------------+--------+---------1 abcd.2345.0099 static Fa0/21 abcd.0070.0070 static Fa0/21 abcd.2345.0099 static Fa0/21 abcd.2345.0099 static Fa0/21 00d0.d333.7f34 static Fa0/21 abcd.2345.0099 static Fa0/21 0005.6667.0007 static Fa0/2This is an example of output from the show mac-address-table count vlan 1 command:
Switch# show mac-address-table count vlan 1MAC Entries for Vlan 1 :Dynamic Address Count: 1Static Address (User-defined) Count: 41Total MAC Addresses In Use:42Remaining MAC addresses: 8150This is an example of output from the show mac-address-table aging-time command:
Switch> show mac-address-table aging-timeVlan Aging Time---- ----------1 4502 3003 600300 450301 450This is an example of output from the show mac-address-table aging-time vlan 1 command:
Switch> show mac-address-table aging-time vlan 1Vlan Aging Time---- ----------1 450Related Commands
clear mac-address-table dynamic
Deletes from the MAC address table a specific dynamic address, all dynamic addresses on a particular interface, or all dynamic addresses on a particular VLAN.
show mac-address-table multicast
Use the show mac-address-table multicast user EXEC command to display the Layer 2 multicast entries for the switch or for the VLAN.
show mac-address-table multicast [vlan vlan-id] [count] [igmp-snooping | user] [ | {begin | exclude | include} expression]
Syntax Description
Defaults
This command has no default setting.
Command Modes
User EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mac-address-table multicast vlan 1 command:
Switch# show mac-address-table multicast vlan 1Vlan Mac Address Type Ports---- ----------- ---- -----1 0100.5e00.0128 IGMP Fa0/111 0100.5e01.1111 USER Fa0/5, Fa0/6, Fa0/7, Fa0/11This is an example of output from the show mac-address-table multicast count command:
Switch# show mac-address-table multicast countMulticast Mac Entries for all vlans: 10This is an example of output from the show mac-address-table multicast vlan 1 count command:
Switch# show mac-address-table multicast vlan 1 countMulticast Mac Entries for vlan 1: 2This is an example of output from the show mac-address-table multicast vlan 1 user command:
Switch# show mac-address-table multicast vlan 1 uservlan mac address type ports-----+----------------+-------+---------------------1 0100.5e02.0203 user Fa0/1,Fa0/2,Fa0/4This is an example of output from the show mac-address-table multicast vlan 1 igmp-snooping count command:
Switch# show mac-address-table multicast vlan 1 igmp-snooping countNumber of igmp-snooping programmed entries : 1show mac-address-table notification
Use the show mac-address-table notification user EXEC command to display parameters for the MAC notification feature.
show mac-address-table notification [interface interface-id] [ | {begin | exclude | include} expression]
Syntax Description
Defaults
This command has no default setting.
Command Modes
User EXEC
Command History
Usage Guidelines
Use the show mac-address-table notification command without keywords to display parameters for all interfaces.
Use this command with the interface keyword to display parameters for a specific interface.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mac-address-table notification command:
Switch> show mac-address-table notificationMAC Notification Feature is Disabled on the switchRelated Commands
clear mac-address-table notification
Clears the MAC address notification global counters.
Enables the MAC notification feature.
Enables MAC-notification traps on a port.
show mls masks
Use the show mls masks user EXEC command to display the details of the Access Control Parameters (ACPs) used for quality of service (QoS) and security access control lists (ACLs).
show mls masks [qos | security] [ | {begin | exclude | include} expression]
This command is available only if your switch is running the enhanced software image.
Syntax Description
Note
Command Modes
User EXEC
Command History
Usage Guidelines
Use the show mls mask command without keywords to display all ACPs configured on the switch.
Use this command with the qos keyword to display the ACPs used for QoS ACLs.
Use this command with the security keyword to display the ACPs used for security ACLs.
Note
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mls masks command:
Switch> show mls masksMask1Type : qosFields : ip-sa(0.0.0.255), ip-da(host), dest-portPolicymap: pmap1Interfaces: Fa0/9, Gi0/1Policymap: pmap2Interfaces: Fa0/1, Fa0/5, Fa0/13Mask2Type : securityFields : mac-sa (host), ethertypeAccess-group: 3Interfaces: Fa0/2, Fa0/6Access-group: macag1Interfaces: Fa0/16In this example, Mask 1 is a QoS ACP consisting an IP source address (with wildcard bits 0.0.0.255), an IP destination address, and Layer 4 destination port fields. This ACP is used by the QoS policy maps pmap1 and pmap2.
Mask 2 is a security ACP consisting of a MAC source address and ethertype fields. This ACP is used by the MAC security access groups 3 and macag1.
Related Commands
show mls qos interface
Use the show mls qos interface user EXEC command to display quality of service (QoS) information at the interface level.
show mls qos interface [interface-id] [policers] [ | {begin | exclude | include} expression]
Syntax Description
Note
Command Modes
User EXEC
Command History
Usage Guidelines
Though visible in the command-line help string, the policers keyword is available only when your switch is running the enhanced software image.
Use the show mls qos interface command without keywords to display parameters for all interfaces.
Use the show mls qos interface interface-id command to display the parameters for a specific interface.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mls qos interface fastethernet0/1 command:
Switch> show mls qos interface fastethernet0/1FastEthernet0/1trust state: trust cosCOS override: disdefault COS: 0Related Commands
show mls qos maps
Use the show mls qos maps user EXEC command to display quality of service (QoS) mapping information. Maps are used to generate an internal Differentiated Services Code Point (DSCP) value, which represents the priority of the traffic.
show mls qos maps [cos-dscp | dscp-cos] [ | {begin | exclude | include} expression]
This command is available only if your switch is running the enhanced software image.
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
Use the show mls qos maps command without keywords to display all maps.
Use this command with the cos-dscp keyword to display the CoS-to-DSCP map.
Use this command with the dscp-cos keyword to display the DSCP-to-CoS map.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mls qos maps cos-dscp command:
Switch> show mls qos maps cos-dscpCos-dscp map:cos: 0 1 2 3 4 5 6 7--------------------------------dscp: 8 8 8 8 24 32 56 56This is an example of output from the show mls qos maps dscp-cos command:
Switch> show mls qos maps dscp-cosDscp-cos map:dscp: 0 8 10 16 18 24 26 32 34 40 46 48 56-----------------------------------------------cos: 0 1 1 1 2 2 3 3 4 4 5 6 7This is an example of output from the show mls qos maps command:
Switch> show mls qos mapsDscp-cos map:dscp: 0 8 10 16 18 24 26 32 34 40 46 48 56-----------------------------------------------cos: 0 1 1 2 2 3 7 4 4 5 5 7 7Cos-dscp map:cos: 0 1 2 3 4 5 6 7--------------------------------dscp: 0 8 16 24 32 40 48 56Related Commands
show monitor
Use the show monitor user EXEC command to display Switch Port Analyzer (SPAN) session information.
show monitor [session session-number] [ | {begin | exclude | include} expression]
Syntax Description
Defaults
This command has no default setting.
Command Modes
User EXEC
Command History
12.1(6)EA2
This command was first introduced. It replaced the show port monitor command.
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show monitor command:
Switch> show monitorSession 1---------Source Ports:RX Only: NoneTX Only: NoneBoth: NoneDestination Ports: NoneRelated Commands
Enables SPAN monitoring on a port and configures a port as a source or destination port.
show mvr
Use the show mvr privileged EXEC command without keywords to display the Multicast VLAN Registration (MVR) global parameter values, including whether or not MVR is enabled, the MVR multicast VLAN, the maximum query response time, the number of multicast groups, and the MVR mode (dynamic or compatible).
show mvr [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mvr command:
Switch# show mvrMVR Running: TRUEMVR multicast vlan: 1MVR Max Multicast Groups: 256MVR Current multicast groups: 256MVR Global query response time: 5 (tenths of sec)MVR Mode: compatibleIn the previous example, the maximum number of multicast groups is 256. The MVR mode is either compatible (for interoperability with Catalyst 2900 XL and Catalyst 3500 XL switches) or dynamic (where operation is consistent with Internet Group Management Protocol [IGMP] snooping operation, and dynamic MVR membership on source ports is supported).
Related Commands
show mvr interface
Use the show mvr interface privileged EXEC command without keywords to display the Multicast VLAN Registration (MVR) receiver and source ports. Use the command with keywords to display MVR parameters for a specific receiver port.
show mvr interface [interface-id [members [vlan vlan-id]] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
If the entered port identification is a non-MVR port or a source port, the command returns an error message. For receiver ports, it displays the port type, per port status, and Immediate-Leave setting.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mvr interface command:
Switch# show mvr interfacePort Type Status Immediate Leave---- ---- ------- ---------------Gi0/1 SOURCE ACTIVE/UP DISABLEDGi0/2 RECEIVER ACTIVE/DOWN DISABLEDIn the previous example, Status is defined as:
•
•
•
This is an example of output from the show mvr interface gigabitethernet0/2 command:
Switch# show mvr interface gigabitethernet0/2Type: RECEIVER Status: ACTIVE Immediate Leave: DISABLEDThis is an example of output from the show mvr interface fastethernet0/6 member command:
Switch# show mvr interface fastethernet0/6 member239.255.0.0 DYNAMIC ACTIVE239.255.0.1 DYNAMIC ACTIVE239.255.0.2 DYNAMIC ACTIVE239.255.0.3 DYNAMIC ACTIVE239.255.0.4 DYNAMIC ACTIVE239.255.0.5 DYNAMIC ACTIVE239.255.0.6 DYNAMIC ACTIVE239.255.0.7 DYNAMIC ACTIVE239.255.0.8 DYNAMIC ACTIVE239.255.0.9 DYNAMIC ACTIVERelated Commands
show mvr members
Use the show mvr members privileged EXEC command to display all receiver ports that are members of an IP multicast group.
show mvr members [ip-address] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The show mvr members command only applies to receiver ports. All source ports are members of all multicast groups.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show mvr members command:
Switch# show mvr membersMVR Group IP Status Members------------ ------ -------239.255.0.1 ACTIVE Gi0/1(d), Gi0/2(s)239.255.0.2 INACTIVE None239.255.0.3 INACTIVE None239.255.0.4 INACTIVE None239.255.0.5 INACTIVE None239.255.0.6 INACTIVE None239.255.0.7 INACTIVE None239.255.0.8 INACTIVE None239.255.0.9 INACTIVE None239.255.0.10 INACTIVE None<output truncated>239.255.0.255 INACTIVE None239.255.1.0 INACTIVE NoneThis is an example of output from the show mvr members 239.255.0.2 command. It shows how to view the members of the IP multicast group 239.255.0.2.
Switch# show mvr member 239.255.0.2239.255.0.2 ACTIVE Gi0/1(d), Gi0/2(d)Related Commands
show pagp
Use the show pagp user EXEC command to display Port Aggregation Protocol (PAgP) channel-group information.
show pagp [channel-group-number] {counters | internal | neighbor} [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
You can enter any show pagp command to display the active port channel information. To display the nonactive information, enter the show pagp command with a group number.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show pagp 1 counters command:
Switch> show pagp 1 countersInformation FlushPort Sent Recv Sent Recv--------------------------------------Channel group: 1Gi0/1 45 42 0 0Gi0/2 45 41 0 0This is an example of output from the show pagp 1 internal command:
Switch> show pagp 1 internalFlags: S - Device is sending Slow hello. C - Device is in Consistent state.A - Device is in Auto mode.Timers: H - Hello timer is running. Q - Quit timer is running.S - Switching timer is running. I - Interface timer is running.Channel group 1Hello Partner PAgP Learning GroupPort Flags State Timers Interval Count Priority Method IfindexGi0/1 SC U6/S7 H 30s 1 128 Any 16Gi0/2 SC U6/S7 H 30s 1 128 Any 16This is an example of output from the show pagp 1 neighbor command:
Switch> show pagp 1 neighborFlags: S - Device is sending Slow hello. C - Device is in Consistent state.A - Device is in Auto mode. P - Device learns on physical port.Channel group 1 neighborsPartner Partner Partner Partner GroupPort Name Device ID Port Age Flags Cap.Gi0/1 device-p2 0002.4b29.4600 Gi0/1 9s SC 10001Gi0/2 device-p2 0002.4b29.4600 Gi0/2 24s SC 10001Related Commands
Clears PAgP channel-group information.
Sets the source-address learning method of incoming packets received from an EtherChannel port.
show policy-map
Use the show policy-map user EXEC command to display quality of service (QoS) policy maps, which define classification criteria for incoming traffic. Policy maps can include policers that specify the bandwidth limitations and the action to take if the limits are exceeded.
show policy-map [policy-map-name [class class-name]] [ | {begin | exclude | include} expression]
This command is available only if your switch is running the enhanced software image.
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
Use the show policy-map command without keywords to display all policy maps configured on the switch.
Note
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show policy-map command:
Switch> show policy-mapPolicy Map bumbumDescription: this is a description.Policy Map wizard_policy3class wizard_1-1-1-2set ip dscp 34Policy Map testPolicy Map policytestclass classtestset ip dscp 20police 10000000 8192 exceed-action dropThis is an example of output from the show policy-map policytest command:
Switch> show policy-map policytestPolicy Map policytestclass classtestset ip dscp 20police 10000000 8192 exceed-action dropThis is an example of output from the show policy-map policytest class classtest command:
Switch> show policy-map policytest class classtestset ip dscp 20police 10000000 8192 exceed-action dropRelated Commands
Creates or modifies a policy map that can be attached to multiple interfaces to specify a service policy.
show port-security
Use the show port-security privileged EXEC command to display the port security settings defined for an interface or for the switch.
show port-security [interface interface-id] [address] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
12.1(6)EA2
This command was first introduced. It replaced the show port security and show mac-address-table secure commands.
Usage Guidelines
If you enter this command without keywords, the output includes the administrative and the operational status of all secure ports on the switch.
If you enter an interface-id, the show port-security command displays port security settings for the interface.
If you enter the address keyword, the show port-security address command displays the secure MAC addresses for all interfaces and the aging information for each secure address.
If you enter an interface-id and the address keyword, the show port-security interface interface-id address command displays all the MAC addresses for the interface with aging information for each secure address. You can also use this command to display all the MAC addresses for an interface even if you have not enabled port security on it.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show port-security command:
Switch# show port-securitySecure Port MaxSecureAddr CurrentAddr SecurityViolation SecurityAction(Count) (Count) (Count)-------------------------------------------------------------------------------Fa0/1 11 11 0 ShutdownFa0/5 15 5 0 RestrictFa0/11 5 4 0 Protect-------------------------------------------------------------------------------Total Addresses in System :21Max Addresses limit in System :1024This is an example of output from the show port-security interface fastethernet0/2 command:
Switch# show port-security interface fastethernet0/2Port Security :EnabledPort status :SecureUpViolation mode :ShutdownMaximum MAC Addresses :11Total MAC Addresses :11Configured MAC Addresses :3Aging time :20 minsAging type :InactivitySecureStatic address aging :EnabledSecurity Violation count :0This is an example of output from the show port-security address command:
Switch# show port-security addressSecure Mac Address Table-------------------------------------------------------------------Vlan Mac Address Type Ports Remaining Age(mins)---- ----------- ---- ----- -------------1 0001.0001.0001 SecureDynamic Fa0/1 15 (I)1 0001.0001.0002 SecureDynamic Fa0/1 15 (I)1 0001.0001.1111 SecureConfigured Fa0/1 16 (I)1 0001.0001.1112 SecureConfigured Fa0/1 -1 0001.0001.1113 SecureConfigured Fa0/1 -1 0005.0005.0001 SecureConfigured Fa0/5 231 0005.0005.0002 SecureConfigured Fa0/5 231 0005.0005.0003 SecureConfigured Fa0/5 231 0011.0011.0001 SecureConfigured Fa0/11 25 (I)1 0011.0011.0002 SecureConfigured Fa0/11 25 (I)-------------------------------------------------------------------Total Addresses in System :10Max Addresses limit in System :1024This is an example of output from the show port-security interface fastethernet0/5 address command:
Switch# show port-security interface fastethernet0/5 addressSecure Mac Address Table-------------------------------------------------------------------Vlan Mac Address Type Ports Remaining Age(mins)---- ----------- ---- ----- -------------1 0005.0005.0001 SecureConfigured Fa0/5 19 (I)1 0005.0005.0002 SecureConfigured Fa0/5 19 (I)1 0005.0005.0003 SecureConfigured Fa0/5 19 (I)-------------------------------------------------------------------Total Addresses:3Related Commands
Enables port security on a port, restricts the use of the port to a user-defined group of stations, and configures secure MAC addresses.
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
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show rps command. Table 2-12 describes the possible output.
Switch# show rpsGREEN
show running-config vlan
Use the show running-config vlan privileged EXEC command to display all or a range of VLAN-related configurations on the switch.
show running-config vlan [vlan-ids] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
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
This is an example of output from the show running-config vlan command:
Switch# show running-config vlan 900-2005Building configuration...Current configuration:!vlan 907!vlan 920!vlan 1025!vlan 2000!vlan 2001endRelated Commands
show spanning-tree
Use the show spanning-tree user EXEC command to display spanning-tree state information.
show spanning-tree [active [detail] | backbonefast | blockedports | bridge | detail [active] | inconsistentports | interface interface-id | mst | pathcost method | root | summary [totals] | uplinkfast | vlan vlan-id] [ | {begin | exclude | include} expression]
show spanning-tree vlan vlan-id [active [detail] | blockedports | bridge | detail [active] | inconsistentports | interface interface-id | root | summary] [ | {begin | exclude | include} expression
show spanning-tree {vlan vlan-id} bridge [address | detail | forward-time | hello-time | id | max-age | priority [system-id] | protocol] [ | {begin | exclude | include} expression]
show spanning-tree {vlan vlan-id} root [address | cost | detail | forward-time | hello-time | id | max-age | port | priority [system-id] [ | {begin | exclude | include} expression]
show spanning-tree interface interface-id [active [detail] | cost | detail [active] | inconsistency | portfast | priority | rootcost | state] [ | {begin | exclude | include} expression]
show spanning-tree mst [configuration | instance-id] [detail | interface interface-id [detail]]
[ | {begin | exclude | include} expression]Syntax Description
Command Modes
User EXEC; indicated keywords available only in privileged EXEC mode
Command History
Usage Guidelines
If the vlan-id variable is omitted, the command applies to the spanning-tree instance for all VLANs.
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
This is an example of output from the show spanning-tree active command:
Switch# show spanning-tree activeVLAN0001Spanning tree enabled protocol ieeeRoot ID Priority 32768Address 0001.4297.e000Cost 57Port 1 (GigabitEthernet0/1)Hello Time 2 sec Max Age 20 sec Forward Delay 15 secBridge ID Priority 32769 (priority 32768 sys-id-ext 1)Address 0002.4b29.7a00Hello Time 2 sec Max Age 20 sec Forward Delay 15 secAging Time 300Interface Port ID Designated Port IDName Prio.Nbr Cost Sts Cost Bridge ID Prio.Nbr---------------- -------- --------- --- --------- -------------------- --------Gi0/1 128.1 19 FWD 38 32768 0030.9441.62c1 128.25Gi0/2 128.2 19 FWD 57 32769 0002.4b29.7a00 128.2Po1 128.65 19 FWD 57 32769 0002.4b29.7a00 128.65This is an example of output from the show spanning-tree detail command:
Switch> show spanning-tree detailVLAN0001 is executing the ieee compatible Spanning Tree protocolBridge Identifier has priority 32768, sysid 1, address 0002.4b29.7a00Configured hello time 2, max age 20, forward delay 15Current root has priority 32768, address 0001.4297.e000Root port is 1 (GigabitEthernet0/1), cost of root path is 57Topology change flag not set, detected flag not setNumber of topology changes 2 last change occurred 2d18h agofrom Port-channel1Times: hold 1, topology change 35, notification 2hello 2, max age 20, forward delay 15Timers: hello 0, topology change 0, notification 0, aging 300Port 1 (GigabitEthernet0/1) of VLAN0001 is forwardingPort path cost 19, Port priority 128, Port Identifier 128.1.Designated root has priority 32768, address 0001.4297.e000Designated bridge has priority 32768, address 0030.9441.62c1Designated port id is 128.25, designated path cost 38Timers: message age 4, forward delay 0, hold 0Number of transitions to forwarding state: 1BPDU: sent 2, received 120638<output truncated>This is an example of output from the show spanning-tree interface fastethernet 0/1 command:
Switch> show spanning-tree interface fastethernet0/1Vlan Port ID Designated Port IDName Prio.Nbr Cost Sts Cost Bridge ID Prio.Nbr---------------- -------- --------- --- --------- -------------------- --------VLAN0001 128.1 19 FWD 38 32768 0030.9441.62c1 128.25This is an example of output from the show spanning-tree summary command:
Switch> show spanning-tree summaryRoot bridge for: none.Extended system ID is enabledPortFast BPDU Guard is disabledEtherChannel misconfiguration guard is enabledUplinkFast is disabledBackboneFast is disabledDefault pathcost method used is shortName Blocking Listening Learning Forwarding STP Active-------------------- -------- --------- -------- ---------- ----------VLAN1 13 0 0 1 14VLAN2 1 0 0 1 2VLAN3 1 0 0 1 2<output truncated>This is an example of output from the show spanning-tree mst configuration command:
Switch# show spanning-tree mst configurationName [region1]Revision 1Instance Vlans Mapped-------- ------------------0 1-9,21-40941 10-20----------------------------This is an example of output from the show spanning-tree mst interface fastethernet0/1 command:
Switch# show spanning-tree mst interface fastethernet0/1FastEthernet0/1 of MST00 is root forwardingEdge port: no (default) port guard : none (default)Link type: point-to-point (auto) bpdu filter: disable (default)Boundary : boundary (STP) bpdu guard : disable (default)Bpdus sent 5, received 74Instance role state cost prio vlans mapped-------- ---- ----- --------- ---- --------------------------------------------0 root FWD 200000 128 1,12,14-4094This is an example of output from the show spanning-tree mst 0 command:
Switch# show spanning-tree mst 0###### MST00 vlans mapped: 1-9,21-4094Bridge address 0002.4b29.7a00 priority 32768 (32768 sysid 0)Root address 0001.4297.e000 priority 32768 (32768 sysid 0)port Gi0/1 path cost 200038IST master *this switchOperational hello time 2, forward delay 15, max age 20, max hops 20Configured hello time 2, forward delay 15, max age 20, max hops 20Interface role state cost prio type-------------------- ---- ----- --------- ---- --------------------------------GigabitEthernet0/1 root FWD 200000 128 P2P bound(STP)GigabitEthernet0/2 desg FWD 200000 128 P2P bound(STP)Port-channel1 desg FWD 200000 128 P2P bound(STP)Related Commands
show storm-control
Use the show storm-control user 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 storm-control [interface-id] [{broadcast | history | multicast | unicast }] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
12.1(6)EA2
This command was first introduced. It replaced the show port storm-control command.
Usage Guidelines
If the variable interface-id is omitted, the show storm-control command displays storm-control settings for all ports on the switch.
You can display broadcast, multicast, or unicast packet-storm information by using the corresponding keyword. When no option is specified, the default is to display broadcast storm-control information.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show storm-control broadcast command:
Switch> show storm-control broadcastInterface Filter State Trap State Upper Lower Current Traps Sent--------- ------------- ------------- ------- ------- ------- ----------Fa0/1 <inactive> <inactive> 100.00% 100.00% 0.00% 0Fa0/2 <inactive> <inactive> 100.00% 100.00% 0.00% 0Fa0/3 <inactive> <inactive> 100.00% 100.00% 0.00% 0Fa0/4 Forwarding Below rising 30.00% 20.00% 20.32% 17. . . .Table 2-13 lists the show storm-control field descriptions.
This is an example of output from the show storm-control fastethernet0/4 history command, which displays the ten most recent storm events for an interface.
Switch> show storm-control fastethernet0/4 historyInterface Fa0/4 Storm Event HistoryEvent Type Event Start Time Duration (seconds)------------------ ---------------- ------------------Unicast 04:58:18 206Broadcast 05:01:54 n/aMulticast 05:01:54 n/aUnicast 05:01:54 108Broadcast 05:05:00 n/aMulticast 05:05:00 n/aUnicast 05:06:00 n/aBroadcast 05:09:39 n/aMulticast 05:09:39 n/aBroadcast 05:11:32 172
Note
Related Commands
show system mtu
Use the show system mtu privileged EXEC command to display the global maximum packet size or maximum transmission unit (MTU) set for the switch.
show system mtu [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show system mtu command:
Switch# show system mtuSystem MTU size is 1500 bytesRelated Commands
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
Command Modes
User EXEC
Command History
Usage Guidelines
If you do not enter an interface-id, the administrative and the operational UDLD status for all interfaces appear.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show udld gigabitethernet0/1 command. In this example, UDLD is enabled on both ends of the link, and UDLD detects that the link is bidirectional. Table 2-14 describes the fields in this example.
Switch> show udld gigabitethernet0/1Interface gi0/1---Port enable administrative configuration setting: Follows device defaultPort enable operational state: EnabledCurrent bidirectional state: BidirectionalCurrent operational state: Advertisement - Single Neighbor detectedMessage interval: 60Time out interval: 5Entry 1Expiration time: 146Device ID: 1Current neighbor state: BidirectionalDevice name: 0050e2826000Port ID: Gi0/2Neighbor echo 1 device: SAD03160954Neighbor echo 1 port: Gi0/1Message interval: 5CDP Device name: 066527791
Table 2-14 show udld Field Descriptions
Interface
The interface on the local device configured for UDLD.
Port enable administrative configuration setting
How UDLD is configured on the port. If UDLD is enabled or disabled, the port enable configuration setting is the same as the operational enable state. Otherwise, the enable operational setting depends on the global enable setting.
Port enable operational state
Operational state that shows whether UDLD is actually running on this port.
Current bidirectional state
The bidirectional state of the link. An unknown state appears if the link is down or if it is connected to an UDLD-incapable device. A bidirectional state appears if the link is a normal two-way connection to a UDLD-capable device. All other values mean miswiring.
Current operational state
The phase of the UDLD state machine. For a normal bidirectional link, the state machine is usually in the Advertisement phase.
Message interval
How often advertisement messages are sent from the local device. Measured in seconds.
Time out interval
The time period, in seconds, that UDLD waits for echoes from a neighbor device during the detection window.
Entry 1
Information from the first cache entry, which contains a copy of echo information received from the neighbor.
Expiration time
The amount of time in seconds remaining before this cache entry is aged out.
Device ID
The neighbor device identification.
Current neighbor state
The neighbor's state. If both the local and neighbor devices are running UDLD, the neighbor state and the local state is bidirectional. If the link is down or the neighbor is not UDLD-capable, no cache entries appear.
Device name
The neighbor MAC address.
Port ID
The neighbor port ID enabled for UDLD.
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.
Message interval
The rate, in seconds, at which the neighbor is sending advertisement messages.
CDP1 device name
CDP name of the device.
1 CDP = Cisco Discovery Protocol
Related Commands
Enables UDLD on all ports on the switch.
Enables UDLD on a port.
Resets any interface that was shut down by UDLD.
show version
Use the show version user EXEC command to display version information for the hardware and firmware.
show version [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show version command:
Switch> show versionCisco Internetwork Operating System SoftwareIOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(9)EA1Copyright (c) 1986-2002 by cisco Systems, Inc.Compiled Wed 27-Feb-02 06:51 by antoninoImage text-base:0x80010000, data-base:0x804E2000ROM:Bootstrap program is C2950 boot loaderSwitch uptime is 1 hour, 54 minutesSystem returned to ROM by power-onSystem image file is "flash:c2950-i6q4l2-mz.121-0.0.9.EA1.bin"cisco WS-C2950G-12-EI (RC32300) processor with 20830K bytes of memory.Last reset from system-resetRunning Enhanced Image12 FastEthernet/IEEE 802.3 interface(s)2 Gigabit Ethernet/IEEE 802.3 interface(s)32K bytes of flash-simulated non-volatile configuration memory.Base ethernet MAC Address:00:05:74:28:09:C0Configuration register is 0xFshow vlan
Use the show vlan user EXEC command to display the parameters for all configured VLANs or one VLAN (if the VLAN ID or name is specified) on the switch.
show vlan [brief | id vlan-id || name vlan-name | summary] [ | {begin | exclude | include} expression]
Syntax DescriptionN
Note
Command Modes
User EXEC
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(9)EA1
The summary keyword was added.
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
This is an example of output from the show vlan command. Table 2-15 describes each field in the display.
Switch> show vlanVLAN Name Status Ports---- -------------------------------- --------- -------------------------------1 default active Fa0/1, Fa0/2, Fa0/5, Fa0/7Fa0/8, Fa0/9, Fa0/11, Fa0/12Gi0/1, Gi0/22 VLAN0002 active51 VLAN0051 active52 VLAN0052 active100 VLAN0100 suspended Fa0/3400 VLAN0400 suspended1002 fddi-default active1003 token-ring-default active1004 fddinet-default active1005 trnet-default activeVLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------1 enet 100001 1500 - - - - - 1002 10032 enet 100002 1500 - - - - - 0 051 enet 100051 1500 - - - - - 0 052 enet 100052 1500 - - - - - 0 0100 enet 100100 1500 - - - - - 0 0400 enet 100400 1500 - - - - - 0 01002 fddi 101002 1500 - - - - - 1 10031003 tr 101003 1500 1005 3276 - - srb 1 10021004 fdnet 101004 1500 - - 1 ieee - 0 01005 trnet 101005 1500 - - 15 ibm - 0 0
This is an example of output from the show vlan brief command:
Switch> show vlan briefVLAN Name Status Ports---- -------------------------------- --------- -------------------------------1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4Fa0/5, Fa0/6, Fa0/7, Fa0/8Fa0/9, Fa0/10, Fa0/11, Fa0/121002 fddi-default active1003 token-ring-default active1004 fddinet-default active1005 trnet-default activeThis is an example of output from the show vlan id command. The specified VLAN is in the extended VLAN range.
Switch# show vlan id 2005VLAN Name Status Ports---- -------------------------------- --------- -------------------------------2005 VLAN2005 active Fa0/2VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------2005 enet 102005 1500 - - - - - 0 0This is an example of output from the show vlan summary command:
Switch> show vlan summaryNumber of existing VLANs : 7Number of existing VTP VLANs : 7Number of existing extended VLANs : 0Related Commands
show vmps
Use the show vmps user EXEC command without keywords to display the VLAN Query Protocol (VQP) version, reconfirmation interval, retry count, VLAN Membership Policy Server (VMPS) IP addresses, and the current and primary servers, or use the statistics keyword to display client-side statistics.
show vmps [statistics] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show vmps command:
Switch> show vmpsVQP Client Status:--------------------VMPS VQP Version: 1Reconfirm Interval: 60 minServer Retry Count: 3VMPS domain server:Reconfirmation status---------------------VMPS Action: otherThis is an example of output from the show vmps statistics command. Table 2-16 describes each field in the example.
Switch> show vmps statisticsVMPS Client Statistics----------------------VQP Queries: 0VQP Responses: 0VMPS Changes: 0VQP Shutdowns: 0VQP Denied: 0VQP Wrong Domain: 0VQP Wrong Version: 0VQP Insufficient Resource: 0
Related Commands
show vtp
Use the show vtp user EXEC command to display general information about the VLAN Trunking Protocol (VTP) management domain, status, and counters.
show vtp {counters | status} [ | {begin | exclude | include} expression]
Syntax Description
Command Modes
User EXEC
Command History
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
This is an example of output from the show vtp counters command. Table 2-17 describes each field in the display.
Switch> show vtp countersVTP statistics:Summary advertisements received : 38Subset advertisements received : 0Request advertisements received : 0Summary advertisements transmitted : 13Subset advertisements transmitted : 3Request advertisements transmitted : 0Number of config revision errors : 0Number of config digest errors : 0Number of V1 summary errors : 0VTP pruning statistics:Trunk Join Transmitted Join Received Summary advts received fromnon-pruning-capable device---------------- ---------------- ---------------- ---------------------------Fa0/9 827 824 0Fa0/10 827 823 0Fa0/11 827 823 0
This is an example of output from the show vtp status command. Table 2-18 describes each field in the display.
Switch> show vtp statusVTP Version : 2Configuration Revision : 0Maximum VLANs supported locally : 250Number of existing VLANs : 5VTP Operating Mode : ServerVTP Domain Name :VTP Pruning Mode : DisabledVTP V2 Mode : DisabledVTP Traps Generation : DisabledMD5 digest : 0xBF 0x86 0x94 0x45 0xFC 0xDF 0xB5 0x70Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00Local updater ID is 172.20.135.196 on interface Vl1 (lowest numbered VLAN interface found)
Related Commands
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
Command Modes
User EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show wrr-queue bandwidth command:
Switch> show wrr-queue bandwidthWRR Queue : 1 2 3 4Bandwidth : 10 20 30 40Related Commands
Displays the mapping of the CoS to the priority queues.
Assigns WRR weights to the four CoS priority queues.
Assigns CoS values to the CoS 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
Command Modes
User EXEC
Command History
Usage Guidelines
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output do not appear, but the lines that contain Output appear.
Examples
This is an example of output from the show wrr-queue cos-map command:
Switch> show wrr-queue cos-mapCoS Value : 0 1 2 3 4 5 6 7Priority Queue : 1 1 2 2 3 3 4 4Related Commands
shutdown
Use the shutdown interface configuration command to disable a port and to shut down the management VLAN. Use the no form of this command to enable 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
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 re-enabled.
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 without the shutdown command displayed.
Examples
This example shows how to disable fixed Fast Ethernet port 0/8 and how to re-enable it:
Switch(config)# interface fastethernet0/8Switch(config-if)# shutdownSwitch(config-if)# no shutdownYou can verify your settings by entering the show interfaces privileged EXEC command.
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
Defaults
No default is defined.
Command Modes
Global configuration
Command History
Usage Guidelines
The shutdown vlan command does not change the VLAN information in the VTP database. It shuts down traffic locally, but the switch still advertises VTP information.
Examples
This example shows how to shutdown traffic on VLAN 2:
Switch(config)# shutdown vlan 2You can verify your setting by entering the show vlan privileged EXEC command.
Related Commands
snmp-server enable traps
Use the snmp-server enable traps global configuration command to enable the switch to send Simple Network Management Protocol (SNMP) notification for various trap types to the network management system (NMS). Use the no form of this command to return to the default setting.
snmp-server enable traps [c2900 | cluster | config | entity | hsrp | mac-notification | rtr | snmp | syslog | vlan-membership | vtp]
no snmp-server enable traps [c2900 | cluster | config | entity | hsrp | mac-notification | rtr | snmp | syslog | vlan-membership | vtp]
Syntax Description
Defaults
The sending of SNMP traps is disabled.
Command Modes
Global configuration
Command History
12.1(6)EA2
This command was first introduced.
12.1(9)EA1
The vlan-membership keyword was added.
Usage Guidelines
Though visible in the command-line help string, the hsrp keyword takes affect only when the enhanced software image is installed.
Specify the host (NMS) that receives the traps by using the snmp-server host global configuration command. If no trap types are specified, all trap types are sent.
Examples
This example shows how to send VTP traps to the NMS:
Switch(config)# snmp-server enable traps vtpYou can verify your setting by entering the show vtp status privileged EXEC or the show running-config privileged EXEC command.
Related Commands
snmp-server host
Use the snmp-server host global configuration command to specify the recipient (host) of a Simple Network Management Protocol (SNMP) notification operation. Use the no form of this command to remove the specified host.
snmp-server host host-addr {informs | traps} {version {1 | 2c}} community-string [c2900 | cluster | config | entity | hsrp | mac-notification | rtr | snmp | tty | udp-port | vlan-membership | vtp]
no snmp-server host host-addr {informs | traps} {version {1 | 2c}} community-string [c2900 | cluster | config | entity | hsrp | mac-notification | rtr | snmp | tty | udp-port | vlan-membership | vtp]
Syntax Description
Note
Defaults
This command is disabled by default. No notifications are sent.
If you enter this command with no keywords, the default is to send all trap types to the host. No informs are sent to this host.
If no version keyword is present, the default is version 1.
Though visible in the command-line help string, the hsrp keyword takes affect only when the enhanced software image is installed.
Note
Command Modes
Global configuration
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(6)EA2
The cluster, mac-notification, and rtr keywords were added.
12.1(9)EA1
The vlan-membership keyword was added.
Usage Guidelines
SNMP notifications can be sent as traps or inform requests. Traps are unreliable because the receiver does not send acknowledgments when it receives traps. The sender cannot determine if the traps were received. However, an SNMP entity that receives an inform request acknowledges the message with an SNMP response PDU. If the sender never receives the response, the inform request can be sent again. Thus, informs are more likely to reach their intended destinations.
However, informs consume more resources in the agent and in the network. Unlike a trap, which is discarded as soon as it is sent, an inform request must be held in memory until a response is received or the request times out. Traps are also sent only once, but an inform might be retried several times. The retries increase traffic and contribute to a higher overhead on the network.
If you do not enter an snmp-server host command, no notifications are sent. To configure the switch to send SNMP notifications, you must enter at least one snmp-server host command. If you enter the command with no keywords, all trap types are enabled for the host. To enable multiple hosts, you must enter a separate snmp-server host command for each host. You can specify multiple notification types in the command for each host.
When multiple snmp-server host commands are given for the same host and kind of notification (trap or inform), each succeeding command overwrites the previous command. Only the last snmp-server host command is in effect. For example, if you enter an snmp-server host inform command for a host and then enter another snmp-server host inform command for the same host, the second command replaces the first.
The snmp-server host command is used with the snmp-server enable traps global configuration command. Use the snmp-server enable traps command to specify which SNMP notifications are sent globally. For a host to receive most notifications, at least one snmp-server enable traps command and the snmp-server host command for that host must be enabled. Some notification types cannot be controlled with the snmp-server enable traps command. For example, some notification types are always enabled. Other notification types are enabled by a different command.
The no snmp-server host command with no keywords disables traps, but not informs, to the host. To disable informs, use the no snmp-server host informs command.
Examples
This example shows how to configure a unique SNMP community string named comaccess for traps and prevent SNMP polling access with this string through access-list 10:
Switch(config)# snmp-server community comaccess ro 10Switch(config)# snmp-server host 172.20.2.160 comaccessSwitch(config)# access-list 10 deny anyThis example shows how to send the SNMP traps to the host specified by the name myhost.cisco.com. The community string is defined as comaccess:
Switch(config)# snmp-server enable trapsSwitch(config)# snmp-server host myhost.cisco.com comaccess snmpThis example shows how to enable the switch to send all traps to the host myhost.cisco.com using the community string public:
Switch(config)# snmp-server enable trapsSwitch(config)# snmp-server host myhost.cisco.com publicRelated Commands
snmp trap mac-notification
Use the snmp trap mac-notification interface configuration command to enable the MAC notification traps on a port. Use the no form of this command to disable the traps and to return the port to default settings.
snmp trap mac-notification [added | removed]
no snmp trap mac-notification [added | removed]
Syntax Description
added
(Optional) Enable MAC notification traps when a MAC address is added to a port.
removed
(Optional) Enable MAC notification traps when a MAC address is removed from a port.
Defaults
The Simple Network Management Protocol (SNMP) address-addition and address-removal traps are disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
Even though you enable the notification trap for a specific interface by using the snmp trap mac-notification command, the trap is generated only when you enter the snmp-server enable traps mac-notification and the mac-address-table notification global configuration commands.
Examples
This example shows how to enable an address-addition trap on a port:
Switch(config-if)# snmp trap mac-notification addedThis example shows how to enable an address-removal trap on a port:
Switch(config-if)# snmp trap mac-notification removedYou can verify your settings by entering the show mac-address-table notification privileged EXEC command.
Related Commands
clear mac-address-table notification
Clears the MAC address notification global counters.
Enables the MAC notification feature on a switch.
Displays MAC notification parameters.
Enables SNMP notification for various trap types.
spanning-tree backbonefast
Use the spanning-tree backbonefast global configuration command to enable the BackboneFast feature. Use the no form of the command to return to the default setting.
spanning-tree backbonefast
no spanning-tree backbonefast
Syntax Description
This command has no arguments or keywords.
Defaults
BackboneFast is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
The BackboneFast feature is supported only when the switch is running per-VLAN spanning-tree (PVST).
BackboneFast is started when a root port or blocked port on a switch receives inferior bridge protocol data units (BPDUs) from its designated bridge. An inferior BPDU identifies one switch as both the root bridge and the designated bridge. When a switch receives an inferior BPDU, it means that a link to which the switch is not directly connected (an indirect link) has failed (that is, the designated bridge has lost its connection to the root switch). If there are alternate paths to the root switch, BackboneFast causes the maximum aging time on the ports on which it received the inferior BPDU to expire and allows a blocked port to move immediately to the listening state. BackboneFast then transitions the interface to the forwarding state. For more information, refer to the Catalyst 2950 Desktop Switch Software Configuration Guide.
Enable BackboneFast on all supported switches to allow the detection of indirect link failures and to start the spanning-tree reconfiguration sooner.
Examples
This example shows how to enable BackboneFast on the switch:
Switch(config)# spanning-tree backbonefastYou can verify your setting by entering the show spanning-tree summary privileged EXEC command.
Related Commands
show spanning-tree summary
Displays a summary of the spanning-tree port states.
spanning-tree bpdufilter
Use the spanning-tree bpdufilter interface configuration command to prevent a port from sending or receiving bridge protocol data units (BPDUs). Use the no form of this command to return to the default setting.
spanning-tree bpdufilter {disable | enable}
no spanning-tree bpdufilter
Syntax Description
disable
Disable BPDU filtering on the specified interface.
enable
Enable BPDU filtering on the specified interface.
Defaults
BPDU filtering is disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
You can enable the BPDU filtering feature when the switch is operating in the per-VLAN spanning-tree (PVST) or the multiple spanning-tree (MST) mode. The MST mode is available only if you have the enhanced software image installed on your switch.
Caution
You can globally enable BPDU filtering on all Port Fast-enabled ports by using the spanning-tree portfast bpdufilter default global configuration command.
You can use the spanning-tree bpdufilter interface configuration command to override the setting of the spanning-tree portfast bpdufilter default global configuration command.
Examples
This example shows how to enable the BPDU filtering feature on a port:
Switch(config)# interface fastethernet0/1Switch(config-if)# spanning-tree bpdufilter enableYou can verify your setting by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree bpduguard
Use the spanning-tree bpduguard interface configuration command to put a port in the error-disabled state when it receives a bridge protocol data unit (BPDU). Use the no form of this command to return to the default setting.
spanning-tree bpduguard {disable | enable}
no spanning-tree bpduguard
Syntax Description
disable
Disable BPDU guard on the specified interface.
enable
Enable BPDU guard on the specified interface.
Defaults
BPDU guard is disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
The BPDU guard feature provides a secure response to invalid configurations because you must manually put the port back in service. Use the BPDU guard feature in a service-provider network to prevent a port from being included in the spanning-tree topology.
You can enable the BPDU guard feature when the switch is operating in the per-VLAN spanning-tree (PVST) or the multiple spanning-tree (MST) mode. The MST mode is available only if you have the enhanced software image installed on your switch.
You can globally enable BPDU guard on all Port Fast-enabled ports by using the spanning-tree portfast bpduguard default global configuration command.
You can use the spanning-tree bpduguard interface configuration command to override the setting of the spanning-tree portfast bpduguard default global configuration command.
Examples
This example shows how to enable the BPDU guard feature on a port:
Switch(config)# interface fastethernet0/1Switch(config-if)# spanning-tree bpduguard enableYou can verify your setting by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree cost
Use the spanning-tree cost interface configuration command to set the path cost for spanning-tree calculations. If a loop occurs, spanning tree considers the path cost when selecting an interface to place in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree [vlan vlan-id] cost cost
no spanning-tree [vlan vlan-id] cost
Syntax Description
Defaults
The default path cost is computed from the interface bandwidth setting. These are the IEEE default path cost values:
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Command Modes
Interface configuration
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(9)EA1
The range for the cost variable increased.
Usage Guidelines
When you configure the cost, higher values represent higher costs.
You can set a cost on a VLAN that does not exist. The setting takes effect when the VLAN exists.
Examples
This example shows how to set a path cost of 250 on an interface (an access port):
Switch(config)# interface fastethernet0/4Switch(config-if)# spanning-tree cost 250This example shows how to set a path cost of 300 for VLAN 10 on an interface that is a trunk port:
Switch(config-if)# spanning-tree vlan 10 cost 300You can verify your settings by entering the show spanning-tree interface interface-id privileged EXEC command.
Related Commands
show spanning-tree interface interface-id
Displays spanning-tree information for the specified interface.
Configures an interface priority.
spanning-tree vlan priority
Sets the switch priority for the specified spanning-tree instance.
spanning-tree extend system-id
Use the spanning-tree extend system-id global configuration command to enable the extended system ID feature.
spanning-tree extend system-id
Note
Syntax Description
This command has no arguments or keywords.
Defaults
The extended system ID is enabled.
Command Modes
Global configuration
Command History
Usage Guidelines
In Release 12.1(9)EA1 and later, Catalyst 2950 switches support the 802.1T spanning-tree extensions, and some of the bits previously used for the switch priority are now used for the extended system ID (VLAN identifier for the per-VLAN spanning-tree [PVST] or an instance identifier for the multiple spanning tree [MST]). In earlier releases, the switch priority is a 16-bit value.
The spanning tree uses the extended system ID, the switch priority, and the allocated spanning-tree MAC address to make the bridge ID unique for each VLAN or multiple spanning-tree instance. With earlier releases, spanning tree used one MAC address per VLAN to make the bridge ID unique for each VLAN.
Support for the extended system ID affects how you manually configure the root switch, the secondary root switch, and the switch priority of a VLAN. For more information, see the "spanning-tree mst root" and the "spanning-tree vlan" sections.
If your network consists of switches that do not support the extended system ID and switches that do support it, it is unlikely that the switch with the extended system ID support will become the root switch. The extended system ID increases the switch priority value every time the VLAN number is greater than the priority of the connected switches running older software.
Related Commands
show spanning-tree summary
Displays a summary of spanning-tree port states.
Configures the multiple spanning-tree (MST) root switch priority and timers based on the network diameter.
spanning-tree vlan priority
Sets the switch priority for the specified spanning-tree instance.
spanning-tree guard
Use the spanning-tree guard interface configuration command to enable root guard or loop guard on all the VLANs associated with the selected interface. Root guard restricts which interface is allowed to be the spanning-tree root port or the path-to-the root for the switch. Loop guard prevents alternate or root ports from becoming designated ports when a failure creates a unidirectional link. Use the no form of this command to return to the default setting.
spanning-tree guard {loop | none | root}
no spanning-tree guard
Syntax Description
Defaults
Root guard is disabled.
Loop guard is configured according to the spanning-tree loopguard default global configuration command (globally disabled).
Command Modes
Interface configuration
Command History
12.1(6)EA2
This command was first introduced. It replaced the spanning-tree rootguard command.
12.1(9)EA1
The loop keyword was added.
Usage Guidelines
You can enable root guard or loop guard when the switch is operating in the per-VLAN spanning-tree (PVST) or the multiple spanning-tree (MST) mode. However, you cannot enable both features at the same time. The MST mode is available only if you have the enhanced software image installed on your switch.
When root guard 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. The root port provides the best path from the switch to the root switch.
When the no spanning-tree guard or the no spanning-tree guard none command is entered, root guard is disabled for all VLANs on the selected interface. If this interface is in the root-inconsistent (blocked) state, it automatically transitions to the listening state.
Do not enable root guard on interfaces that will be used by the UplinkFast feature. With UplinkFast, the backup interfaces (in the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the backup interfaces used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and prevented from reaching the forwarding state. The UplinkFast feature is not available when the switch is operating in MST mode.
Loop guard is most effective when it is configured on the entire switched network. When the switch is operating in PVST mode, loop guard prevents alternate and root ports from becoming designated ports, and spanning tree does not send bridge protocol data units (BPDUs) on root or alternate ports. When the switch is operating in MST mode, BPDUs are not sent on nonboundary ports only if the port is blocked by loop guard in all MST instances. On a boundary port, loop guard blocks the port in all MST instances.
To disable root guard or loop guard, use the spanning-tree guard none interface configuration command. You cannot enable both root guard and loop guard at the same time.
You can override the setting of the spanning-tree loopguard default global configuration command by using the spanning-tree guard loop interface configuration command.
Examples
This example shows how to enable root guard on all the VLANs associated with the specified interface:
Switch(config)# interface fastethernet0/3Switch(config-if)# spanning-tree guard rootThis example shows how to enable loop guard on all the VLANs associated with the specified interface:
Switch(config)# interface fastethernet0/3Switch(config-if)# spanning-tree guard loopYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
show running-config
Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference for Release 12.1 > Cisco IOS File Management Commands > Configuration File Commands.
Sets the path cost for spanning-tree calculations.
Prevents alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link.
Configures the path cost for MST calculations.
Configures an interface priority.
Configures the MST root switch priority and timers based on the network diameter.
Configures an interface priority.
spanning-tree vlan priority
Sets the switch priority for the specified spanning-tree instance.
spanning-tree link-type
Use the spanning-tree link-type interface configuration command to override the default link-type setting, which is determined by the duplex mode of the port, and to enable Rapid Spanning-Tree Protocol (RSTP) transitions to the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree link-type {point-to-point | shared}
no spanning-tree link-type
Syntax Description
point-to-point
Specify that the link type of a port is point-to-point.
shared
Specify that the link type of a port is shared.
Defaults
The switch derives the link type of a port from the duplex mode. A full-duplex port is considered a point-to-point link, and a half-duplex port is considered a shared link.
Command Modes
Interface configuration
Command History
Usage Guidelines
You can override the default setting of the link type by using the spanning-tree link-type command; for example, a half-duplex link can be physically connected point-to-point to a single port on a remote switch running RSTP and be enabled for rapid transitions.
Examples
This example shows how to specify the link type as shared (regardless of the duplex setting) and to prevent RSTP rapid transitions to the forwarding state:
Switch(config-if)# spanning-tree link-type sharedYou can verify your settings by entering the show spanning-tree mst interface interface-id privileged EXEC command.
Related Commands
show spanning-tree mst interface interface-id
Displays multiple spanning-tree (MST) information for the specified interface.
spanning-tree loopguard default
Use the spanning-tree loopguard default global configuration command to prevent alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link. Use the no form of this command to return to the default setting.
spanning-tree loopguard default
no spanning-tree loopguard default
Syntax Description
This command has no arguments or keywords.
Defaults
Loop guard is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
You can enable the loop guard feature when the switch is operating in the per-VLAN spanning-tree (PVST) or the multiple spanning-tree (MST) mode. The MST mode is available only if you have the enhanced software image installed on your switch.
Loop guard is most effective when it is configured on the entire switched network. When the switch is operating in PVST mode, loop guard prevents alternate and root ports from becoming designated ports, and spanning tree does not send bridge protocol data units (BPDUs) on root or alternate ports. When the switch is operating in MST mode, BPDUs are not sent on nonboundary ports only if the port is blocked by loop guard in all MST instances. On a boundary port, loop guard blocks the port in all MST instances.
Loop guard operates only on ports that are considered point-to-point by the spanning tree.
You can override the setting of the spanning-tree loopguard default global configuration command by using the spanning-tree guard loop interface configuration command.
Examples
This example shows how to globally enable loop guard:
Switch(config)# spanning-tree loopguard defaultYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
show running-config
Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference for Release 12.1 > Cisco IOS File Management Commands > Configuration File Commands.
spanning-tree guard loop
Enables the loop guard feature on all the VLANs associated with the specified interface.
spanning-tree mode
Use the spanning-tree mode global configuration command to enable either per-VLAN spanning-tree (PVST) or multiple spanning tree (MST) on your switch. Use the no form of this command to return to the default setting.
spanning-tree mode {mst | pvst}
no spanning-tree mode
Syntax Description
mst
Enable MST. This keyword is available only if your switch is running the enhanced software image.
pvst
Enable PVST.
Defaults
The default mode is PVST.
Command Modes
Global configuration
Command History
Usage Guidelines
You cannot run both PVST and MST at the same time.
Caution
Examples
This example shows to enable MST on the switch:
Switch(config)# spanning-tree mode mstYou can verify your setting by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree mst configuration
Use the spanning-tree mst configuration global configuration command to enter multiple spanning-tree (MST) configuration mode through which you configure the MST region. Use the no form of this command to return to the default settings.
spanning-tree mst configuration
no spanning-tree mst configuration
This command is available only if your switch is running the enhanced software image.
Syntax Description
This command has no arguments or keywords.
Defaults
The default mapping is that all VLANs are mapped to the common and internal spanning tree (CIST) instance (instance 0).
The default name is an empty string.
The revision number is 0.
Command Modes
Global configuration
Command History
Usage Guidelines
Entering the spanning-tree mst configuration command enables the MST configuration mode. These configuration commands are available:
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When you map VLANs to an MST instance, the mapping is incremental, and the range of VLANs specified is added or removed to the existing ones. To specify a range, use a hyphen; for example, instance 1 vlan 1-63 maps VLANs 1 to 63 to MST instance 1. To specify a series, use a comma; for example, instance 1 vlan 10, 20, 30 maps VLANs 10, 20, and 30 to MST instance 1.
All VLANs that are not explicitly mapped to an MST instance are mapped to the common and internal spanning tree (CIST) instance (instance 0) and cannot be unmapped from the CIST by using the no form of the command.
For two or more switches to be in the same MST region, they must have the same VLAN mapping, the same configuration revision number, and the same name.
Examples
This example shows how to enter MST configuration mode, map VLAN 10 to 20 to MST instance 1, name the region region1, set the configuration revision to 1, display the pending configuration, apply the changes, and return to global configuration mode:
Switch# spanning-tree mst configurationSwitch(config-mst)# instance 1 vlan 10-20Switch(config-mst)# name region1Switch(config-mst)# revision 1Switch(config-mst)# show pendingPending MST configurationName [region1]Revision 1Instance Vlans Mapped-------- ---------------------0 1-9,21-40941 10-20-------------------------------Switch(config-mst)# exitSwitch(config)#This example shows how to add VLANs 1 to 100 to the ones already mapped (if any) to instance 2, to move VLANs 40 to 60 that were previously mapped to instance 2 to the CIST instance, to add VLAN 10 to instance 10, and to remove all the VLANs mapped to instance 2 and map them to the CIST instance:
Switch(config-mst)# instance 2 vlan 1-100Switch(config-mst)# no instance 2 vlan 40-60Switch(config-mst)# instance 10 vlan 10Switch(config-mst)# no instance 2You can verify your settings by entering the show pending MST configuration command.
Related Commands
show spanning-tree mst configuration
Displays the MST region configuration.
spanning-tree mst cost
Use the spanning-tree mst cost interface configuration command to set the path cost for multiple spanning-tree (MST) calculations. If a loop occurs, spanning tree considers the path cost when selecting an interface to put in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree mst instance-id cost cost
no spanning-tree mst instance-id cost
This command is available only if your switch is running the enhanced software image.
Syntax Description
instance-id
ID associated with a spanning-tree instance. The range is 0 to 15.
cost
Path cost is 1 to 200000000, with higher values meaning higher costs.
Defaults
The default path cost is computed from the interface bandwidth setting. These are the IEEE default path cost values:
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Command Modes
Interface configuration
Command History
Usage Guidelines
When you configure the cost, higher values represent higher costs.
Examples
This example shows how to set a path cost of 250 on an interface associated with instance 2:
Switch(config)# interface fastethernet0/4Switch(config-if)# spanning-tree mst 2 cost 250You can verify your settings by entering the show spanning-tree mst interface interface-id privileged EXEC command.
Related Commands
show spanning-tree mst interface interface-id
Displays MST information for the specified interface.
Configures an interface priority.
Configures the switch priority for the specified spanning-tree instance.
spanning-tree mst forward-time
Use the spanning-tree mst forward-time global configuration command to set the forward-delay time for all multiple spanning-tree (MST) instances. The forwarding time determines how long each of the listening and learning states last before the interface begins forwarding. Use the no form of this command to return to the default setting.
spanning-tree mst forward-time seconds
no spanning-tree mst forward-time
This command is available only if your switch is running the enhanced software image.
Syntax Description
Defaults
The default is 15 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
Changing the spanning-tree mst forward-time command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree forwarding time to 18 seconds for all MST instances:
Switch(config)# spanning-tree mst forward-time 18You can verify your settings by entering the show spanning-tree mst privileged EXEC command.
Related Commands
spanning-tree mst hello-time
Use the spanning-tree mst hello-time global configuration command to set the interval between hello bridge protocol data units (BPDUs) sent by root switch configuration messages. Use the no form of this command to return to the default setting.
spanning-tree mst hello-time seconds
no spanning-tree mst hello-time
This command is available only if your switch is running the enhanced software image.
Syntax Description
seconds
Interval between hello BPDUs sent by root switch configuration messages. The range is 1 to 10 seconds.
Defaults
The default is 2 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
After you set the spanning-tree mst max-age seconds global configuration command, if a switch does not receive BPDUs from the root switch within the specified interval, the switch recomputes the spanning-tree topology. The max-age setting must be greater than the hello-time setting.
Changing the spanning-tree mst hello-time command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree hello time to 3 seconds for all MST instances:
Switch(config)# spanning-tree mst hello-time 3You can verify your settings by entering the show spanning-tree mst privileged EXEC command.
Related Commands
spanning-tree mst max-age
Use the spanning-tree mst max-age global configuration command to set the interval between messages that 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 topology. Use the no form of this command to return to the default setting.
spanning-tree mst max-age seconds
no spanning-tree mst max-age
This command is available only if your switch is running the enhanced software image.
Syntax Description
Defaults
The default is 20 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
After you set the spanning-tree mst max-age seconds global configuration command, if a switch does not receive BPDUs from the root switch within the specified interval, the switch recomputes the spanning-tree topology. The max-age setting must be greater than the hello-time setting.
Changing the spanning-tree mst max-age command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree max-age to 30 seconds for all MST instances:
Switch(config)# spanning-tree mst max-age 30You can verify your settings by entering the show spanning-tree mst privileged EXEC command.
Related Commands
spanning-tree mst max-hops
Use the spanning-tree mst max-hops global configuration command to set the number of hops in a region before the bridge protocol data unit (BPDU) is discarded and the information held for a port is aged. Use the no form of this command to return to the default setting.
spanning-tree mst max-hops hop-count
no spanning-tree mst max-hops
This command is available only if your switch is running the enhanced software image.
Syntax Description
Defaults
The default is 20 hops.
Command Modes
Global configuration
Command History
Usage Guidelines
The root switch of the instance always sends a BPDU (or M-record) with a cost of 0 and the hop count set to the maximum value. When a switch receives this BPDU, it decrements the received remaining hop count by one and propagates the decremented count as the remaining hop count in the generated M-records. A switch discards the BPDU and ages the information held for the port when the count reaches 0.
Changing the spanning-tree mst max-hops command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree max-hops to 10 for all MST instances:
Switch(config)# spanning-tree mst max-hops 10You can verify your settings by entering the show spanning-tree mst privileged EXEC command.
Related Commands
spanning-tree mst port-priority
Use the spanning-tree mst port-priority interface configuration command to configure an interface priority. If a loop occurs, the Multiple Spanning Tree Protocol (MSTP) can determine which interface to put in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree mst instance-id port-priority priority
no spanning-tree mst instance-id port-priority
This command is available only if your switch is running the enhanced software image.
Syntax Description
instance-id
ID associated with a spanning-tree instance. The range is 0 to 15.
priority
Number from 0 to 255. The lower the number, the higher the priority.
Defaults
The default is 128.
Command Modes
Interface configuration
Command History
Usage Guidelines
You can assign higher priority values (lower numerical values) to interfaces that you want selected first and lower priority values (higher numerical values) that you want selected last. If all interfaces have the same priority value, the MST puts the interface with the lowest interface number in the forwarding state and blocks other interfaces.
Examples
This example shows how to increase the likelihood that the interface associated with spanning-tree instance 20 is placed into the forwarding state if a loop occurs:
Switch(config)# interface fastethernet0/2Switch(config-if)# spanning-tree mst 20 port-priority 0You can verify your settings by entering the show spanning-tree mst interface interface-id privileged EXEC command.
Related Commands
show spanning-tree mst interface interface-id
Displays MST information for the specified interface.
Sets the path cost for MST calculations.
Sets the switch priority for the specified spanning-tree instance.
spanning-tree mst priority
Use the spanning-tree mst priority global configuration command to set the switch priority for the specified spanning-tree instance. Use the no form of this command to return to the default setting.
spanning-tree mst instance-id priority priority
no spanning-tree mst instance-id priority
This command is available only if your switch is running the enhanced software image.
Syntax Description
Defaults
The default is 32768.
Command Modes
Global configuration
Command History
Examples
This example shows how to set the spanning-tree priority to 8192 for multiple spanning-tree (MST) instance 20:
Switch(config)# spanning-tree mst 20 priority 8192You can verify your settings by entering the show spanning-tree mst instance-id privileged EXEC command.
Related Commands
show spanning-tree mst instance-id
Displays MST information for the specified interface.
Sets the path cost for MST calculations.
Configures an interface priority.
spanning-tree mst root
Use the spanning-tree mst root global configuration command to configure the multiple spanning-tree (MST) root switch priority and timers based on the network diameter. Use the no form of this command to return to the default setting.
spanning-tree mst instance-id root {primary | secondary} [diameter net-diameter
[hello-time seconds]]no spanning-tree mst instance-id root
This command is available only if your switch is running the enhanced software image.
Syntax Description
Defaults
The primary root switch priority is 24576.
The secondary root switch priority is 28672.
The hello time is 2 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
Use the spanning-tree mst instance-id root command used only on backbone switches.
When you enter the spanning-tree mst instance-id root command, the software tries to set a high enough priority to make this switch the root of the spanning-tree instance. Because of the extended system ID support, the switch sets the switch priority for the instance to 24576 if this value will cause this switch to become the root for the specified instance. If any root switch for the specified instance has a switch priority lower than 24576, the switch sets its own priority to 4096 less than the lowest switch priority. (4096 is the value of the least-significant bit of a 4-bit switch priority value.)
When you enter the spanning-tree mst instance-id root secondary command, because of support for the extended system ID, the software changes the switch priority from the default value (32768) to 28672. If the root switch fails, this switch becomes the next root switch (if the other switches in the network use the default switch priority of 32768 and are therefore unlikely to become the root switch).
Examples
This example shows how to configure the switch as the root switch for instance 10 with a network diameter of 4:
Switch(config)# spanning-tree mst 10 root primary diameter 4This example shows how to configure the switch as the secondary root switch for instance 10 with a network diameter of 4:
Switch(config)# spanning-tree mst 10 root secondary diameter 4You can verify your settings by entering the show spanning-tree mst instance-id privileged EXEC command.
Related Commands
show spanning-tree mst instance-id
Displays MST information for the specified instance.
Sets the forward-delay time for all MST instances.
Sets the interval between hello BPDUs sent by root switch configuration messages.
Sets the interval between messages that the spanning tree receives from the root switch.
Sets the number of hops in a region before the BPDU is discarded.
spanning-tree port-priority
Use the spanning-tree port-priority interface configuration command to configure an interface priority. If a loop occurs, spanning tree can determine which interface to put in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree [vlan vlan-id] port-priority priority
no spanning-tree [vlan vlan-id] port-priority
Syntax Description
Defaults
The default is 128.
Command Modes
Interface configuration
Command History
Usage Guidelines
If the variable vlan-id is omitted, the command applies to the spanning-tree instance associated with VLAN 1.
You can set the priority on a VLAN that has no interfaces assigned to it. The setting takes effect when you assign the interface to the VLAN.
Examples
This example shows how to increase the likelihood that the Fast Ethernet interface 0/2 will be put in the forwarding state if a loop occurs:
Switch(config)# interface fastethernet0/2Switch(config-if)# spanning-tree vlan 20 port-priority 0You can verify your settings by entering the show spanning-tree interface interface-id privileged EXEC command.
Related Commands
show spanning-tree interface interface-id
Displays spanning-tree information for the specified interface.
Sets the path cost for spanning-tree calculations.
spanning-tree vlan priority
Sets the switch priority for the specified spanning-tree instance.
spanning-tree portfast (global configuration)
Use the spanning-tree portfast global configuration command to globally enable bridge protocol data unit (BPDU) filtering on Port Fast-enabled ports, the BPDU guard feature on Port Fast-enabled ports, or the Port Fast feature on all nontrunking ports. The BPDU filtering feature prevents the switch port from sending or receiving BPDUs. The BPDU guard feature puts Port Fast-enabled ports that receive BPDUs in an error-disabled state. Use the no form of this command to return to the default setting.
spanning-tree portfast {bpdufilter default | bpduguard default | default}
no spanning-tree portfast {bpdufilter default | bpduguard default | default}
Syntax Description
Defaults
The BPDU filtering, the BPDU guard, and the Port Fast features are disabled on all ports unless they are individually configured.
Command Modes
Global configuration
Command History
12.1(6)EA2
This command was first introduced.
12.1(9)EA1
The bpdufilter default and default keywords were added.
Usage Guidelines
You can enable these features when the switch is operating in the per-VLAN spanning-tree (PVST) or the multiple spanning-tree (MST) mode. The MST mode is available only if you have the enhanced software image installed on your switch.
Use the spanning-tree portfast bpdufilter default global configuration command to globally enable BPDU filtering on ports that are Port Fast-enabled (the ports are in a Port Fast-operational state). The ports still send a few BPDUs at link-up before the switch begins to filter outbound BPDUs. You should globally enable BPDU filtering on a switch so that hosts connected to switch ports do not receive BPDUs. If a BPDU is received on a Port Fast-enabled port, the port loses its Port Fast-operational status and BPDU filtering is disabled.
You can override the spanning-tree portfast bpdufilter default global configuration command by using the spanning-tree bdpufilter interface configuration command.
Caution
Use the spanning-tree portfast bpduguard default global configuration command to globally enable BPDU guard on ports that are in a Port Fast-operational state. In a valid configuration, Port Fast-enabled ports do not receive BPDUs. Receiving a BPDU on a Port Fast-enabled port signals an invalid configuration, such as the connection of an unauthorized device, and the BPDU guard feature puts the port in the error-disabled state. The BPDU guard feature provides a secure response to invalid configurations because you must manually put the port back in service. Use the BPDU guard feature in a service-provider network to prevent an access port from participating in the spanning tree.
You can override the spanning-tree portfast bpduguard default global configuration command by using the spanning-tree bdpuguard interface configuration command.
Use the spanning-tree portfast default global configuration command to globally enable the Port Fast feature on all nontrunking ports. Configure Port Fast only on ports that connect to end stations; otherwise, an accidental topology loop could cause a data packet loop and disrupt switch and network operation. A Port Fast-enabled port moves directly to the spanning-tree forwarding state when linkup occurs without waiting for the standard forward-delay time.
You can override the spanning-tree portfast default global configuration command by using the spanning-tree portfast interface configuration command. You can use the no spanning-tree portfast default global configuration command to disable Port Fast on all ports unless they are individually configured with the spanning-tree portfast interface configuration command.
Examples
This example shows how to globally enable the BPDU filtering feature:
Switch(config)# spanning-tree portfast bpdufilter defaultThis example shows how to globally enable the BPDU guard feature:
Switch(config)# spanning-tree portfast bpduguard defaultThis example shows how to globally enable the Port Fast feature on all nontrunking ports:
Switch(config)# spanning-tree portfast defaultYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree portfast (interface configuration)
Use the spanning-tree portfast interface configuration command to enable the Port Fast feature on an interface in all its associated VLANs. When the Port Fast feature is enabled, the interface changes directly from a blocking state to a forwarding state without making the intermediate spanning-tree state changes. Use the no form of this command to return to the default setting.
spanning-tree portfast [disable | trunk]
no spanning-tree portfast
Syntax Description
disable
(Optional) Disable the Port Fast feature on the specified interface.
trunk
(Optional) Enable the Port Fast feature on a trunking interface.
Defaults
The Port Fast feature is disabled on all interfaces; however, it is automatically enabled on dynamic-access ports.
Command Modes
Interface configuration
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(9)EA1
The disable and trunk keywords were added.
Usage Guidelines
Use this feature only on interfaces that connect to end stations; otherwise, an accidental topology loop could cause a data packet loop and disrupt switch and network operation.
You can enable this feature when the switch is operating in the per-VLAN spanning-tree (PVST) or the multiple spanning-tree (MST) mode.
This feature affects all VLANs on the interface.
A port with the Port Fast feature enabled is moved directly to the spanning-tree forwarding state without waiting the standard forward-time delay.
You can use the spanning-tree portfast default global configuration command to globally enable the Port Fast feature on all nontrunking interfaces. However, the spanning-tree portfast interface configuration command can override the global setting.
If you configure the spanning-tree portfast default global configuration command, you can enable Port Fast on a port that is not a trunk port by using the no spanning-tree portfast interface configuration command.
The no spanning-tree portfast interface configuration command is the same as the spanning-tree portfast disable interface configuration command.
Examples
This example shows how to enable the Port Fast feature on an interface:
Switch(config)# interface fastethernet0/2Switch(config-if)# spanning-tree portfastYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree stack-port
Use the spanning-tree stack-port interface configuration command to enable cross-stack UplinkFast (CSUF) on an interface and to accelerate the choice of a new root port when a link or switch fails or when spanning tree reconfigures itself. Use the no form of this command to return to the default setting.
spanning-tree stack-port
no spanning-tree stack-port
Syntax Description
This command has no arguments or keywords.
Defaults
CSUF is disabled on all interfaces.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command is effective only if you enable the UplinkFast feature by using the spanning-tree uplinkfast global configuration command.
Use this command only on access switches.
The CSUF feature is supported only when the switch is running per-VLAN spanning-tree (PVST).
You can enable CSUF only on one stack-port Gigabit Interface Converter (GBIC) interface. The stack port connects to the GigaStack GBIC multidrop backbone. If you try to enable CSUF on a Fast Ethernet or a copper-based Gigabit Ethernet port, you receive an error message.
If CSUF is already enabled on an interface and you try to enable it on another interface, you receive an error message. You must disable CSUF on the first interface before enabling it on a new interface.
Examples
This example shows how to enable CSUF on the GBIC interface:
Switch(config)# interface gigabitethernet0/1Switch(config-if)# spanning-tree stack-portYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
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 the spanning tree reconfigures itself. Use the no form of this command to return to the default setting.
spanning-tree uplinkfast [max-update-rate pkts-per-second]
no spanning-tree uplinkfast [max-update-rate]
Syntax Description
max-update-rate pkts-per-second
(Optional) The number of packets per second at which update packets are sent. The range is 0 to 65535.
Defaults
UplinkFast is disabled.
The update rate is 150 packets per second.
Command Modes
Global configuration
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(6)EA2
The pkts-per-second range was changed to 0 to 65535.
Usage Guidelines
Use this command only on access switches.
The UplinkFast feature is supported only when the switch is running per-VLAN spanning-tree (PVST).
When you enable UplinkFast, it is enabled for the entire switch and cannot be enabled for individual VLANs.
When UplinkFast is enabled, the switch priority of all VLANs is set to 49152. If you change the path cost to a value less than 3000 and you enable UplinkFast or UplinkFast is already enabled, the path cost of all interfaces and VLAN trunks is increased by 3000 (if you change the path cost to 3000 or above, the path cost is not altered). The changes to the switch priority and the path cost reduces the chance that the switch will become the root switch.
When UplinkFast is disabled, the switch priorities of all VLANs and path costs of all interfaces are set to default values if you did not modify them from their defaults.
When spanning tree detects that the root port has failed, UplinkFast immediately switches over to an alternate root port, changing the new root port directly to FORWARDING state. During this time, a topology change notification is sent.
Do not enable the root guard on interfaces that will be used by the UplinkFast feature. With UplinkFast, the backup interfaces (in the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the backup interfaces used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and prevented from reaching the forwarding state.
If you set the max-update-rate to 0, station-learning frames are not generated, so the spanning-tree topology converges more slowly after a loss of connectivity.
Examples
This example shows how to enable UplinkFast:
Switch(config)# spanning-tree uplinkfastYou can verify your setting by entering the show spanning-tree summary privileged EXEC command.
Related Commands
show spanning-tree summary
Displays a summary of the spanning-tree port states.
Enables cross-stack UplinkFast (CSUF) on an interface and accelerates the choice of a new root port when a link or switch fails or when spanning tree reconfigures itself.
spanning-tree vlan root primary
Forces this switch to be the root switch.
spanning-tree vlan
Use the spanning-tree vlan global configuration command to configure spanning tree on a per-VLAN basis. Use the no form of this command to return to the default setting.
spanning-tree vlan vlan-id {forward-time seconds | hello-time seconds | max-age seconds |
priority priority | {root {primary | secondary} [diameter net-diameter
[hello-time seconds]]}}no spanning-tree vlan vlan-id [forward-time | hello-time | max-age | priority | root]
Syntax Description
Defaults
Spanning tree is enabled on all VLANs.
The forward-delay time is 15 seconds.
The hello time is 2 seconds.
The max-age is 20 seconds.
The primary root switch priority is 24576.
The secondary root switch priority is 28672.
Command Modes
Global configuration
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(9)EA1
The priority priority range changed from 1 to 65535 to 1 to 61440 (in increments of 4096).
Usage Guidelines
Disabling the STP causes the VLAN to stop participating in the spanning-tree topology. Interfaces that are administratively down remain down. Received BPDUs are forwarded like other multicast frames. The VLAN does not detect and prevent loops when STP is disabled.
You can disable the STP on a VLAN that is not currently active and verify the change by using the show running-config or the show spanning-tree vlan vlan-id privileged EXEC command. The setting takes effect when the VLAN is activated.
When disabling or re-enabling the STP, you must use a single command lint to specify each VLAN that you want to disable or enable.
When a VLAN is disabled and then enabled, all assigned VLANs continue to be its members. However, all spanning-tree bridge parameters are returned to their previous settings (the last setting before the VLAN was disabled).
You can enable spanning-tree options on a VLAN that has no interfaces assigned to it. The setting takes effect when you assign interfaces to it.
When setting the max-age seconds, if a switch does not receive BPDUs from the root switch within the specified interval, it recomputes the spanning-tree topology. The max-age setting must be greater than the hello-time setting.
The spanning-tree vlan vlan-id root command should be used only on backbone switches.
When you enter the spanning-tree vlan vlan-id root command, the software checks the switch priority of the current root switch for each VLAN. Because of the extended system ID support, the switch sets the switch priority for the specified VLAN to 24576 if this value will cause this switch to become the root for the specified VLAN. If any root switch for the specified VLAN has a switch priority lower than 24576, the switch sets its own priority for the specified VLAN to 4096 less than the lowest switch priority. (4096 is the value of the least-significant bit of a 4-bit switch priority value.)
When you enter the spanning-tree vlan vlan-id root secondary command, because of support for the extended system ID, the software changes the switch priority from the default value (32768) to 28672. If the root switch should fail, this switch becomes the next root switch (if the other switches in the network use the default switch priority of 32768, and therefore, are unlikely to become the root switch).
Examples
This example shows how to disable the STP on VLAN 5:
Switch(config)# no spanning-tree vlan 5You can verify your setting by entering the show spanning-tree privileged EXEC command. In this instance, VLAN 5 does not appear in the list.
This example shows how to set the spanning-tree forwarding time to 18 seconds for VLAN 20:
Switch(config)# spanning-tree vlan 20 forward-time 18This 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 3This example shows how to set spanning-tree max-age to 30 seconds for VLAN 20:
Switch(config)# spanning-tree vlan 20 max-age 30This example shows how to reset the max-age parameter to the default value for spanning-tree instance 100:
Switch(config)# no spanning-tree vlan 100 max-ageThis example shows how to set the spanning-tree priority to 8192 for VLAN 20:
Switch(config)# spanning-tree vlan 20 priority 8192This example shows how to configure the switch as the root switch for VLAN 10 with a network diameter of 4:
Switch(config)# spanning-tree vlan 10 root primary diameter 4This example shows how to configure the switch as the secondary root switch for VLAN 10 with a network diameter of 4:
Switch(config)# spanning-tree vlan 10 root secondary diameter 4You can verify your settings by entering the show spanning-tree vlan vlan-id privileged EXEC command.
Related Commands
show spanning-tree vlan
Displays spanning-tree information.
Sets the path cost for spanning-tree calculations.
Enables the root guard or the loop guard feature for all the VLANs associated with the selected interface.
Sets an interface priority.
Globally enables the BPDU filtering or the BPDU guard feature on Port Fast-enabled ports or enables the Port Fast feature on all nontrunking ports.
Enables the Port Fast feature on an interface in all its associated VLANs.
Enables the UplinkFast feature, which accelerates the choice of a new root port.
speed
Use the speed interface configuration command to specify the speed of a 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
Defaults
For Fast Ethernet and 10/100/1000 ports, the default is auto.
For 100BASE-FX ports, the default is 100 Mbps.
For Gigabit Interface Converter (GBIC)-module ports, the default is 1000 Mbps.
Command Modes
Interface configuration
Command History
Usage Guidelines
Certain Fast Ethernet ports can be configured to be either 10 or 100 Mbps. Applicability of this command is hardware-dependent.
The 100BASE-FX ports on Catalyst 2950C-24 switches do not support the speed command. These ports only operate in 100-Mbps and full-duplex mode.
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 10/100/1000 ports, the speed can be configured at 10, 100, or 1000 Mbps.
GBIC-module ports support only 1000 Mbps. The speed values of 10-Mbps and 100-Mbps are not supported.
Note
If both the speed and duplex are set to specific values, autonegotiation is disabled.
Note
Examples
This example shows how to set port 1 to 100 Mbps:
Switch(config)# interface fastethernet0/1Switch(config-if)# speed 100You can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
storm-control
Use the storm-control interface configuration command to enable broadcast, multicast, or unicast storm control on a port and to specify the action taken when a storm occurs on a port. Use the no form of this command to disable storm control for broadcast, multicast, or unicast traffic and disable the specified storm-control action.
storm-control {{{broadcast | multicast | unicast} level level [lower level]} | action {shutdown | trap}}
no storm-control {{broadcast | multicast | unicast} level} | action}
Syntax Description
Defaults
Broadcast, multicast, and unicast storm control are disabled.
The default action is to filter traffic and to not send an SNMP trap.
Command Modes
Interface configuration
Command History
12.1(6)EA2
This command was first introduced. It replaced port storm-control command.
Usage Guidelines
Use the storm-control command to enable or disable broadcast, multicast, or unicast storm control on a port. After a port is disabled during a storm, use the no shutdown interface configuration command to enable the port.
The suppression levels are entered as a percentage of total bandwidth. A suppression value of 100 percent means that no limit is placed on the specified traffic type. This feature is enabled only when the rising suppression level is less than 100 percent. If no other storm-control configuration is specified, the default action is to filter the traffic causing the storm and to send no SNMP trap.
When a storm occurs and the action is to filter traffic, if the falling suppression level is not specified, the switch blocks all traffic until the traffic rate drops below the rising suppression level. If the falling suppression level is specified, the switch blocks traffic until the traffic rate drops below this level.
When a multicast or unicast storm occurs and the action is to filter traffic, the switch blocks all traffic (broadcast, multicast, and unicast traffic) and sends only Spanning Tree Protocol (STP) packets.
When a broadcast storm occurs and the action is to filter traffic, the switch blocks only broadcast traffic.
The trap and shutdown options are independent of each other.
Examples
This example shows how to enable broadcast storm control on a port with a 75.67 percent rising suppression level:
Switch(config-if)# storm-control broadcast level 75.67This example shows how to enable multicast storm control on a port with a 87 percent rising suppression level and a 65 percent falling suppression level:
Switch(config-if)# storm-control multicast level 87 65This example shows how to enable the shutdown action on a port:
Switch(config-if)# storm-control action shutdownThis example shows how to enable the trap action on a port:
Switch(config-if)# storm-control action trapThis example shows how to disable the shutdown action on a port:
Switch(config-if)# no storm-control action shutdownYou can verify your settings by entering the show storm-control privileged EXEC command.
Related Commands
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 its 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 | dynamic}
no switchport access
Syntax Description
Defaults
All ports are in static-access mode in VLAN 1 if the port is not connected to a device running Dynamic Trunking Protocol (DTP). The default access VLAN for an access port is VLAN 1.
All ports are dynamic trunk ports.
A dynamic-access port is initially a member of no VLAN and receives its assignment based on the packet it receives.
Command Modes
Interface configuration
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(6)EA2
The dynamic keyword was added.
Usage Guidelines
The no switchport access command resets the access mode VLAN to the appropriate default VLAN for the device.
The port must be in access mode before the switchport access vlan command can take effect. For more information, see the switchport mode command.
An access port can be assigned to only one VLAN.
The VMPS server (such as a Catalyst 6000 series switch) must be configured before a port is configured as dynamic.
These restrictions apply to dynamic-access ports:
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Examples
This 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 2You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command and examining information in the Administrative Mode and Operational Mode rows.
Related Commands
show interfaces switchport
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings.
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 | dynamic {auto | desirable} | trunk}
no switchport mode
Syntax Description
Defaults
The default mode is dynamic desirable.
Command Modes
Interface configuration
Command History
12.0(5.2)WC(1)
This command was first introduced.
12.1(6)EA2
The dynamic auto and dynamic desirable keywords were added.
Usage Guidelines
Configuration by using the access or trunk keywords takes affect only when you configure the port in the appropriate mode by using the switchport mode command. The static-access and trunk configurations are saved, but only one configuration is active at a time.
If you enter access mode, the interface changes into permanent nontrunking mode and negotiates to convert the link into a nontrunk link even if the neighboring interface does not agree to the change.
If you enter dynamic auto mode, the interface converts the link to a trunk link if the neighboring interface is set to trunk or desirable mode.
If you enter dynamic desirable mode, the interface becomes a trunk interface if the neighboring interface is set to trunk, desirable, or auto mode.
If you enter trunk mode, the interface changes into permanent trunking mode and negotiates to convert the link into a trunk link even if the interface connecting to it does not agree to the change.
The no switchport mode form resets the mode to dynamic desirable.
Trunk ports cannot coexist on the same switch.
To autonegotiate trunking, the interfaces must be in the same VTP domain. Trunk negotiation is managed by the Dynamic Trunking Protocol (DTP), which is a point-to-point protocol. However, some internetworking devices might forward DTP frames improperly, which could cause misconfigurations. To avoid this, you should configure interfaces connected to devices that do not support DTP to not forward DTP frames, which turns off DTP.
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Examples
This example shows how to configure a port for access mode:
Switch(config-if)# switchport mode accessThis example shows how set the interface to dynamic desirable mode:
Switch(config-if)# switchport mode dynamic desirableThis example shows how to configure a port for trunk mode:
Switch(config-if)# switchport mode trunkYou can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command and examining information in the Administrative Mode and Operational Mode rows.
Related Commands
show interfaces switchport
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings.
Configures a port as a static-access port.
switchport nonegotiate
Use the switchport nonegotiate interface configuration command to specify that Dynamic Trunking Protocol (DTP) negotiation packets are not sent on the Layer 2 interface. The switch does not engage in DTP negotiation on this interface. Use the no form of this command to return to the default setting.
switchport nonegotiate
no switchport nonegotiate
Syntax Description
This command has no arguments or keywords.
Defaults
The default is to use DTP negotiation to determine trunking status.
Command Modes
Interface configuration
Command History
Usage Guidelines
The no form of the switchport nonegotiate command removes nonegotiate status.
This command is valid only when the interface switchport mode is access or trunk (configured by using the switchport mode access or the switchport mode trunk interface configuration command). This command returns an error if you attempt to execute it in dynamic (auto or desirable) mode.
Internetworking devices that do not support DTP might forward DTP frames improperly and cause misconfigurations. To avoid this, you should turn off DTP by using the switchport no negotiate command to configure the interfaces connected to devices that do not support DTP to not forward DTP frames.
When you enter the switchport nonegotiate command, DTP negotiation packets are not sent on the interface. The device does or does not trunk according to the mode parameter given: access or trunk.
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Examples
This example shows how to cause an interface to refrain from negotiating trunking mode and act as a trunk or access port (depending on the mode set):
Switch(config-if)# switchport nonegotiateYou can verify your setting by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces switchport
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings.
Configures the VLAN membership mode of a port.
switchport port-security
Use the switchport port-security interface configuration command without keywords to enable port security on an interface. Use the keywords to configure secure MAC addresses, a maximum number of secure MAC addresses, or the violation mode. Use the no form of this command to disable port security or to set the parameters to their default states.
switchport port-security [mac-address mac-address] | [maximum value] | [violation {protect | restrict | shutdown}]
no switchport port-security [mac-address mac-address] | [maximum value] | [violation {protect | restrict | shutdown}]
Syntax Description
Defaults
Port security is disabled.
When port security is enabled, if no keywords are entered, the default maximum number of secure MAC addresses is 1.
The default violation mode is shutdown.
Command Modes
Interface configuration
Command History
12.1(6)EA2
This command was first introduced. It replaced the port security and mac-address-table secure commands.
Usage Guidelines
After you set the maximum number of secure MAC addresses allowed on a port, you can add secure addresses to the address table by manually configuring all of them, by allowing the port to dynamically configure all of them, or by configuring a number of MAC addresses and allowing the rest to be dynamically configured.
A security violation occurs when the maximum number of secure MAC addresses have been added to the address table and a station whose MAC address is not in the address table attempts to access the interface, or when a station whose MAC address is configured as a secure MAC address on another secure port attempts to access the interface.
If you enable port security on a voice VLAN port and if there is a PC connected to the IP phone, you should set the maximum allowed secure addresses on the port to more than 1.
You cannot configure static secure MAC addresses in the voice VLAN.
If you specify restrict or shutdown, use the snmp-server host global configuration command to configure the Simple Network Management Protocol (SNMP) trap host to receive traps.
You can enable port security on a interface only if the port is not configured as one of these:
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When a secure port is in the error-disabled state, you can bring it out of this state by entering the errdisable recovery cause psecure-violation global configuration command, or you can manually re-enable it by entering the shutdown and no shut down interface configuration commands.
Examples
This example shows how to enable port security:
Switch(config-if)# switchport port-securityThis example shows how to set the action that the port takes when an address violation occurs:
Switch(config-if)# switchport port-security violation shutdownThis example shows how to set the maximum number of addresses that a port can learn to 20.
Switch(config-if)# switchport port-security maximum 20You can verify your settings by entering the show port-security privileged EXEC command.
Related Commands
switchport port-security aging
Use the switchport port-security aging interface configuration command to set the aging time and type for secure address entries or to change the aging behavior for statically configured secure addresses on a particular port. Use the no form of this command to disable port security aging or to set the parameters to their default states.
switchport port-security aging {static | time time | type {absolute | inactivity}}
no switchport port-security aging {static | time | type}
Syntax Description
Defaults
The port security aging feature is disabled. The default time is 0.
The default aging type is absolute.
The default static aging behavior is disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
To enable secure address aging for a particular port, set the port aging time to a value other than 0.
To allow limited-time access to particular secure addresses, set the aging type as absolute. When the aging time lapses, the secure addresses are deleted.
To allow continuous access to a limited number of secure addresses, set the aging type as inactivity. This removes the secure address when it becomes inactive, and other addresses can become secure.
To allow unlimited access to a secure address, configure it as a secure address, and disable aging for the statically configured secure address by using the no switchport port-security aging static interface configuration command.
Examples
This example sets the aging time as 2 hours for absolute aging for all the secure addresses on Fast Ethernet interface 0/1.
Switch(config)# interface fastethernet0/1Switch(config-if)# switchport port-security aging time 120This example sets the aging time as 2 minutes for inactivity aging type for configured secure addresses on Fast Ethernet interface 0/2.
Switch(config)# interface fastethernet0/2Switch(config-if)# switchport port-security aging time 2Switch(config-if)# switchport port-security aging type inactivitySwitch(config-if)# switchport port-security aging staticThis example shows how to disable aging for configured secure addresses.
Switch(config-if)# no switchport port-security aging staticRelated Commands
switchport priority extend
Use the switchport priority extend interface configuration command to set a port priority for the incoming untagged frames or the priority of frames received by the IP phone connected to the specified port. Use the no form of this command to return to the default setting.
switchport priority extend {cos value | none | trust}
no switchport priority extend
Syntax Description
Defaults
The port priority is not set, and the default value for untagged frames received on the port is 0.
The IP phone connected to the port is not instructed (none) what to do with the priority.
Command Modes
Interface configuration
Command History
Examples
This example shows how to configure the IP phone connected to the specified port to trust the received 802.1P priority:
Switch(config-if)# switchport priority extend trustYou can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
Displays the administrative and operational status of a switching (nonrouting) port.
Configures the voice VLAN on the port.
switchport protected
Use the switchport 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 return to the default setting.
switchport protected
no switchport protected
Syntax Description
This command has no keywords or arguments.
Defaults
No protected port is defined. All ports are nonprotected.
Command Modes
Interface configuration
Command History
12.1(6)EA2
This command was first introduced. It replaced the port protected command.
Usage Guidelines
The switchport 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. A protected port is different from a secure port.
A protected port does not forward any unicast, multicast, or broadcast traffic to any other protected port. A protected port continues to forward unicast, multicast, and broadcast traffic to unprotected ports and vice versa.
Port monitoring does not work if both the monitor and monitored ports are protected ports.
Examples
This example shows how to enable a protected port on Fast Ethernet interface 0/3:
Switch(config)# interface fastethernet0/3Switch(config-if)# switchport protectedYou can verify your settings by entering the show interfaces switchport privileged EXEC command.
Related Commands
show interfaces switchport
Displays the administrative and operational staus of a switching port.
switchport trunk
Use the switchport trunk interface configuration command to set the trunk characteristics when the interface is in trunking mode. Use the no form of this command to reset all of the trunking characteristics to the defaults. Use the no form with keywords to reset those characteristics to the defaults.
switchport trunk {{allowed vlan vlan-list} | {native vlan vlan-id} | {pruning vlan vlan-list}}
no switchport trunk {{allowed vlan vlan-list} | {native vlan vlan-id} | {pruning vlan vlan-list}}
Syntax Description
The vlan-list format is all | none | [add | remove | except] vlan-atom where:
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Note
Separate nonconsecutive VLAN IDs with a comma; do not enter a space after the comma. Use a hyphen to designate a range of IDs; do not enter a space before or after the hyphen. Do not enter leading zeros.
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Separate nonconsecutive VLAN IDs with a comma; do not enter a space after the comma. Use a hyphen to designate a range of IDs; do not enter a space before or after the hyphen. Do not enter leading zeros.
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For a list of nonconsecutive VLAN IDs, separate the VLAN IDs with a comma. Do not enter a space after the comma. Do not enter leading zeroes.
For a continuous range of VLAN IDs, use a hyphen to designate the range. Do not enter a space before or after the hyphen. Do not enter leading zeroes.
These are examples showing how to specify one or more VLANs:
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Defaults
VLAN 1 is the default native VLAN ID on the port.
The default for all VLAN lists is to include all VLANs.
Command Modes
Interface configuration
Command History
Usage Guidelines
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.
Allowed VLAN:
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Native VLANs:
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Trunk Pruning:
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Note
Examples
This example shows how to configure VLAN 3 as the default port to send all untagged traffic:
Switch(config-if)# switchport trunk native vlan 3This example shows how to add VLANs 1, 2, 5, and 6 to the allowed list:
Switch(config-if)# switchport trunk allowed vlan add 1,2,5,6This example shows how to remove VLANs 3 and 10 to 15 from the pruning-eligible list:
Switch(config-if)# switchport trunk pruning vlan remove 3,10-15You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces switchport
Displays the administrative and operational status of a switching (nonrouting) port.
Configures the VLAN membership mode of a port.
switchport voice vlan
Use the switchport voice vlan interface configuration command to configure voice VLAN on the port. Use the no form of this command to return to the default setting.
switchport voice vlan {vlan-id | dot1p | none | untagged}
no switchport voice vlan
Syntax Description
Defaults
The switch default is not to automatically configure the telephone (none).
The telephone default is not to tag frames.
Command Modes
Interface configuration
Command History
Usage Guidelines
You should configure voice VLAN on access ports.
If you enable port security on a voice VLAN port and if there is a PC connected to the IP phone, you should set the maximum allowed secure addresses on the port to more than 1.
You cannot configure static secure MAC addresses in the voice VLAN.
The Port Fast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the Port Fast feature is not automatically disabled.
Examples
This example shows how to configure VLAN 2 as the voice VLAN:
Switch(config-if)# switchport voice vlan 2You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces interface-id switchport
Displays the administrative and operational status of a switching (nonrouting) port.
Determines how the device connected to the specified port handles priority traffic received on its incoming port.
system mtu
Use the system mtu global configuration command to set the maximum packet size or maximum transmission unit (MTU) size for the switch. Use the no form of this command to restore the global MTU value to its original default value.
system mtu bytes
no system mtu
Syntax Description
Defaults
The default MTU size is 1500 bytes.
Command Modes
Global configuration
Command History
Usage Guidelines
If you enter a value that is outside of the range for the switch, the value is not accepted.
Note
The size of frames that can be received by the switch CPU is limited to 1500 bytes, no matter what value was entered with the system mtu command. Although frames that are forwarded or routed typically are not received by the CPU, in some cases packets are sent to the CPU, such as traffic sent to control traffic, Simple Network Management Protocol (SNMP), Telnet, or routing protocols.
Examples
This example shows how to set the maximum packet size to 1528 bytes:
Switch(config)# system mtu 1528Switch(config)# exitThis example shows the response when you try to set a switch to an out-of-range number:
Switch(config)# system mtu 2000^% Invalid input detected at '^' marker.You can verify your settings by entering the show system mtu privileged EXEC command.
Related Commands
