Consolidated Platform Command Reference, Cisco IOS XE Release 3.3SE (Cisco WLC 5700 Series)
Layer 2/3 Commands
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Layer 2/3 Commands

Layer 2/3 Commands

channel-group

To assign an Ethernet port to an EtherChannel group, or to enable an EtherChannel mode, or both, use the channel-group command in interface configuration mode. To remove an Ethernet port from an EtherChannel group, use the no form of this command.

channel-group channel-group-number mode { active | auto [ non-silent ] | desirable [ non-silent ] | on | passive }

no channel-group

Syntax Description

channel-group-number

Channel group number. The range is 1 to 128.

mode

Specifies the EtherChannel mode.

active

Unconditionally enables Link Aggregation Control Protocol (LACP).

auto

Enables the Port Aggregation Protocol (PAgP) only if a PAgP device is detected.

non-silent

(Optional) Configures the interface for nonsilent operation when connected to a partner that is PAgP-capable. Use in PAgP mode with the auto or desirable keyword when traffic is expected from the other device.

desirable

Unconditionally enables PAgP.

on

Enables the on mode.

passive

Enables LACP only if a LACP device is detected.

Command Default

No channel groups are assigned.

No mode is configured.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

For Layer 2 EtherChannels, the channel-group command automatically creates the port-channel interface when the channel group gets its first physical port. You do not have to use the interface port-channel command in global configuration mode to manually create a port-channel interface. If you create the port-channel interface first, the channel-group-number can be the same as the port-channel-number, or you can use a new number. If you use a new number, the channel-group command dynamically creates a new port channel.

Although it is not necessary to disable the IP address that is assigned to a physical port that is part of a channel group, we strongly recommend that you do so.

You create Layer 3 port channels by using the interface port-channel command followed by the no switchport interface configuration command. Manually configure the port-channel logical interface before putting the interface into the channel group.

After you configure an EtherChannel, configuration changes that you make on the port-channel interface apply to all the physical ports assigned to the port-channel interface. Configuration changes applied to the physical port affect only the port where you apply the configuration. To change the parameters of all ports in an EtherChannel, apply configuration commands to the port-channel interface, for example, spanning-tree commands or commands to configure a Layer 2 EtherChannel as a trunk.

Active mode places a port into a negotiating state in which the port initiates negotiations with other ports by sending LACP packets. A channel is formed with another port group in either the active or passive mode.

Auto mode places a port into a passive negotiating state in which the port responds to PAgP packets it receives but does not start PAgP packet negotiation. A channel is formed only with another port group in desirable mode. When auto is enabled, silent operation is the default.

Desirable mode places a port into an active negotiating state in which the port starts negotiations with other ports by sending PAgP packets. An EtherChannel is formed with another port group that is in the desirable or auto mode. When desirable is enabled, silent operation is the default.

If you do not specify non-silent with the auto or desirable mode, silent is assumed. The silent mode is used when the controller is connected to a device that is not PAgP-capable and rarely, if ever, sends packets. An example of a silent partner is a file server or a packet analyzer that is not generating traffic. In this case, running PAgP on a physical port prevents that port from ever becoming operational. However, it allows PAgP to operate, to attach the port to a channel group, and to use the port for transmission. Both ends of the link cannot be set to silent.

In on mode, a usable EtherChannel exists only when both connected port groups are in the on mode.


Caution


Use care when using the on mode. This is a manual configuration, and ports on both ends of the EtherChannel must have the same configuration. If the group is misconfigured, packet loss or spanning-tree loops can occur.


Passive mode places a port into a negotiating state in which the port responds to received LACP packets but does not initiate LACP packet negotiation. A channel is formed only with another port group in active mode.

Do not configure an EtherChannel in both the PAgP and LACP modes. EtherChannel groups running PAgP and LACP can coexist on the same controller or on different controllers in the stack (but not in a cross-stack configuration). Individual EtherChannel groups can run either PAgP or LACP, but they cannot interoperate.

If you set the protocol by using the channel-protocol interface configuration command, the setting is not overridden by the channel-group interface configuration command.

Do not configure a port that is an active or a not-yet-active member of an EtherChannel as an IEEE 802.1x port. If you try to enable IEEE 802.1x authentication on an EtherChannel port, an error message appears, and IEEE 802.1x authentication is not enabled.

Do not configure a secure port as part of an EtherChannel or configure an EtherChannel port as a secure port.

For a complete list of configuration guidelines, see the “Configuring EtherChannels” chapter in the software configuration guide for this release.


Caution


Do not enable Layer 3 addresses on the physical EtherChannel ports. Do not assign bridge groups on the physical EtherChannel ports because it creates loops.


Examples

This example shows how to configure an EtherChannel on a single controller in the stack. It assigns two static-access ports in VLAN 10 to channel 5 with the PAgP mode desirable:

Controller# configure terminal
Controller(config)# interface range gigabitethernet2/0/1 -2
Controller(config-if-range)# switchport mode access
Controller(config-if-range)# switchport access vlan 10
Controller(config-if-range)# channel-group 5 mode desirable
Controller(config-if-range)# end

This example shows how to configure an EtherChannel on a single controller in the stack. It assigns two static-access ports in VLAN 10 to channel 5 with the LACP mode active:

Controller# configure terminal
Controller(config)# interface range gigabitethernet2/0/1 -2
Controller(config-if-range)# switchport mode access
Controller(config-if-range)# switchport access vlan 10
Controller(config-if-range)# channel-group 5 mode active
Controller(config-if-range)# end

This example shows how to configure a cross-stack EtherChannel in a controller stack. It uses LACP passive mode and assigns two ports on stack member 2 and one port on stack member 3 as static-access ports in VLAN 10 to channel 5:

Controller# configure terminal
Controller(config)# interface range gigabitethernet2/0/4 -5
Controller(config-if-range)# switchport mode access
Controller(config-if-range)# switchport access vlan 10
Controller(config-if-range)# channel-group 5 mode passive
Controller(config-if-range)# exit
Controller(config)# interface gigabitethernet3/0/3
Controller(config-if)# switchport mode access
Controller(config-if)# switchport access vlan 10
Controller(config-if)# channel-group 5 mode passive
Controller(config-if)# exit

You can verify your settings by entering the show running-config privileged EXEC command.


Related Commands

Command

Description

channel-protocol

Restricts the protocol used on a port to manage channeling.

interface port-channel

Accesses or creates a port channel.

show etherchannel

Displays EtherChannel information for a channel.

show lacp

Displays LACP channel-group information.

show pagp

Displays Port Aggregation Protocol (PAgP) channel-group information.

channel-protocol

To restrict the protocol used on a port to manage channeling, use the channel-protocol command in interface configuration mode. To return to the default setting, use the no form of this command.

channel-protocol { lacp | pagp }

no channel-protocol

Syntax Description

lacp

Configures an EtherChannel with the Link Aggregation Control Protocol (LACP).

pagp

Configures an EtherChannel with the Port Aggregation Protocol (PAgP).

Command Default

No protocol is assigned to the EtherChannel.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

Use the channel-protocol command only to restrict a channel to LACP or PAgP. If you set the protocol by using the channel-protocol command, the setting is not overridden by the channel-group interface configuration command.

You must use the channel-group interface configuration command to configure the EtherChannel parameters. The channel-group command also can set the mode for the EtherChannel.

You cannot enable both the PAgP and LACP modes on an EtherChannel group.

PAgP and LACP are not compatible; both ends of a channel must use the same protocol.

You cannot configure PAgP on cross-stack configurations.

Examples

This example shows how to specify LACP as the protocol that manages the EtherChannel:

Controller(config-if)# channel-protocol lacp

You can verify your settings by entering the show etherchannel [channel-group-number] protocol privileged EXEC command.


Related Commands

Command

Description

channel-group

Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.

show etherchannel

Displays EtherChannel information for a channel.

clear lacp

To clear Link Aggregation Control Protocol (LACP) channel-group counters, use the clear lacp command in privileged EXEC mode.

clear lacp [ channel-group-number ] counters

Syntax Description

channel-group-number

(Optional) Channel group number. The range is 1 to 128.

counters

Clears traffic counters.

Command Default

None

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

You can clear all counters by using the clear lacp counters command, or you can clear only the counters for the specified channel group by using the clear lacp channel-group-number counters command.

Examples

This example shows how to clear all channel-group information:

Controller# clear lacp counters

This example shows how to clear LACP traffic counters for group 4:

Controller# clear lacp 4 counters

You can verify that the information was deleted by entering the show lacp counters or the show lacp channel-group-number counters privileged EXEC command.


Related Commands

Command

Description

show lacp

Displays LACP channel-group information.

clear pagp

To clear the Port Aggregation Protocol (PAgP) channel-group information, use the clear pagp command in privileged EXEC mode.

clear pagp [ channel-group-number ] counters

Syntax Description

channel-group-number

(Optional) Channel group number. The range is 1 to 128.

counters

Clears traffic counters.

Command Default

None

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

You can clear all counters by using the clear pagp counters command, or you can clear only the counters for the specified channel group by using the clear pagp channel-group-number counters command.

Examples

This example shows how to clear all channel-group information:

Controller# clear pagp counters

This example shows how to clear PAgP traffic counters for group 10:

Controller# clear pagp 10 counters

You can verify that the information was deleted by entering the show pagp privileged EXEC command.


Related Commands

Command

Description

debug pagp

Enables debugging of PAgP.

show pagp

Displays Port Aggregation Protocol (PAgP) channel-group information.

debug etherchannel

To enable debugging of EtherChannels, use the debug etherchannel command in privileged EXEC mode. To disable debugging, use the no form of the command.

debug etherchannel [ all | detail | error | event | idb ]

no debug etherchannel [ all | detail | error | event | idb ]

Syntax Description

all

(Optional) Displays all EtherChannel debug messages.

detail

(Optional) Displays detailed EtherChannel debug messages.

error

(Optional) Displays EtherChannel error debug messages.

event

(Optional) Displays EtherChannel event messages.

idb

(Optional) Displays PAgP interface descriptor block debug messages.

Command Default

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The undebug etherchannel command is the same as the no debug etherchannel command.


Note


Although the linecard keyword is displayed in the command-line help, it is not supported.


When you enable debugging on a stack, it is enabled only on the active controller. To enable debugging on the standby controller, start a session from the active controller by using the session switch-number command in privileged EXEC mode. Enter the debug command at the command-line prompt of the standby controller.

To enable debugging on the standby controller without first starting a session on the active controller, use the remote command switch-number LINE command in privileged EXEC mode.

Examples

This example shows how to display all EtherChannel debug messages:

Controller# debug etherchannel all 

This example shows how to display debug messages related to EtherChannel events:

Controller# debug etherchannel event

Related Commands

Command

Description

show etherchannel

Displays EtherChannel information for a channel.

debug lacp

To enable debugging of Link Aggregation Control Protocol (LACP) activity, use the debug lacp command in privileged EXEC mode. To disable LACP debugging, use the no form of this command.

debug lacp [ all | event | fsm | misc | packet ]

no debug lacp [ all | event | fsm | misc | packet ]

Syntax Description

all

(Optional) Displays all LACP debug messages.

event

(Optional) Displays LACP event debug messages.

fsm

(Optional) Displays messages about changes within the LACP finite state machine.

misc

(Optional) Displays miscellaneous LACP debug messages.

packet

(Optional) Displays the receiving and transmitting LACP control packets.

Command Default

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The undebug etherchannel command is the same as the no debug etherchannel command.

When you enable debugging on a stack, it is enabled only on the active controller. To enable debugging on the standby controller, start a session from the active controller by using the session switch-number command in privileged EXEC mode. Enter the debug command at the command-line prompt of the standby controller.

To enable debugging on the standby controller without first starting a session on the active controller, use the remote command switch-number LINE command in privileged EXEC mode.

Examples

This example shows how to display all LACP debug messages:

Controller# debug LACP all 

This example shows how to display debug messages related to LACP events:

Controller# debug LACP event

debug pagp

To enable debugging of Port Aggregation Protocol (PAgP) activity, use the debug pagp command in privileged EXEC mode. To disable PAgP debugging, use the no form of this command.

debug pagp [ all | dual-active | event | fsm | misc | packet ]

no debug pagp [ all | dual-active | event | fsm | misc | packet ]

Syntax Description

all

(Optional) Displays all PAgP debug messages.

dual-active

(Optional) Displays dual-active detection messages.

event

(Optional) Displays PAgP event debug messages.

fsm

(Optional) Displays messages about changes within the PAgP finite state machine.

misc

(Optional) Displays miscellaneous PAgP debug messages.

packet

(Optional) Displays the receiving and transmitting PAgP control packets.

Command Default

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The undebug pagp command is the same as the no debug pagp command.

When you enable debugging on a stack, it is enabled only on the active controller. To enable debugging on the standby controller, start a session from the active controller by using the session switch-number command in privileged EXEC mode. Enter the debug command at the command-line prompt of the standby controller.

To enable debugging on the standby controller without first starting a session on the active controller, use the remote command switch-number LINE command in privileged EXEC mode.

Examples

This example shows how to display all PAgP debug messages:

Controller# debug pagp all 

This example shows how to display debug messages related to PAgP events:

Controller# debug pagp event

debug platform pm

To enable debugging of the platform-dependent port manager software module, use the debug platform pm command in privileged EXEC mode. To disable debugging, use the no form of this command.

debug platform pm { all | counters | errdisable | fec | if-numbers | l2-control | link-status | platform | pm-spi | pm-vectors [detail] | ses | vlans }

no debug platform pm { all | counters | errdisable | fec | if-numbers | l2-control | link-status | platform | pm-spi | pm-vectors [detail] | ses | vlans }

Syntax Description

all

Displays all port manager debug messages.

counters

Displays counters for remote procedure call (RPC) debug messages.

errdisable

Displays error-disabled-related events debug messages.

fec

Displays forwarding equivalence class (FEC) platform-related events debug messages.

if-numbers

Displays interface-number translation event debug messages.

l2-control

Displays Layer 2 control infra debug messages.

link-status

Displays interface link-detection event debug messages.

platform

Displays port manager function event debug messages.

pm-spi

Displays port manager stateful packet inspection (SPI) event debug messages.

pm-vectors

Displays port manager vector-related event debug messages.

detail

(Optional) Displays vector-function details.

ses

Displays service expansion shelf (SES) related event debug messages.

vlans

Displays VLAN creation and deletion event debug messages.

Command Default

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The undebug platform pm command is the same as the no debug platform pm command.

When you enable debugging on a stack, it is enabled only on the active controller. To enable debugging on the standby controller, start a session from the active controller by using the session switch-number command in privileged EXEC mode. Enter the debug command at the command-line prompt of the standby controller.

To enable debugging on the standby controller without first starting a session on the active controller, use the remote command switch-number LINE command in privileged EXEC mode.

Examples

This example shows how to display debug messages related to the creation and deletion of VLANs:

Controller# debug platform pm vlans 

debug platform udld

To enable debugging of the platform-dependent UniDirectional Link Detection (UDLD) software, use the debug platform udld command in privileged EXEC mode. To disable debugging, use the no form of this command.

debug platform udld [ error | event ] [ switch switch-number ]

no debug platform udld [ error | event ] [ switch switch-number ]

Syntax Description

error

(Optional) Displays error condition debug messages.

event

(Optional) Displays UDLD-related platform event debug messages.

switch switch-number

(Optional) Displays UDLD debug messages for the specified stack member.

Command Default

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The undebug platform udld command is the same as the no debug platform udld command.

interface port-channel

To access or create a port channel, use the interface port-channel command in global configuration mode. Use the no form of this command to remove the port channel.

interface port-channel port-channel-number

no interface port-channel

Syntax Description

port-channel-number

Channel group number. The range is 1 to 128.

Command Default

No port channel logical interfaces are defined.

Command Modes

Global configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

For Layer 2 EtherChannels, you do not have to create a port-channel interface before assigning physical ports to a channel group. Instead, you can use the channel-group interface configuration command, which automatically creates the port-channel interface when the channel group obtains its first physical port. If you create the port-channel interface first, the channel-group-number can be the same as the port-channel-number, or you can use a new number. If you use a new number, the channel-group command dynamically creates a new port channel.

You create Layer 3 port channels by using the interface port-channel command followed by the no switchport interface configuration command. You should manually configure the port-channel logical interface before putting the interface into the channel group.

Only one port channel in a channel group is allowed.


Caution


When using a port-channel interface as a routed port, do not assign Layer 3 addresses on the physical ports that are assigned to the channel group.



Caution


Do not assign bridge groups on the physical ports in a channel group used as a Layer 3 port channel interface because it creates loops. You must also disable spanning tree.


Follow these guidelines when you use the interface port-channel command:

  • If you want to use the Cisco Discovery Protocol (CDP), you must configure it on the physical port and not on the port channel interface.
  • Do not configure a port that is an active member of an EtherChannel as an IEEE 802.1x port. If IEEE 802.1x is enabled on a not-yet active port of an EtherChannel, the port does not join the EtherChannel.

For a complete list of configuration guidelines, see the “Configuring EtherChannels” chapter in the software configuration guide for this release.

Examples

This example shows how to create a port channel interface with a port channel number of 5:

Controller(config)# interface port-channel 5

You can verify your setting by entering the show running-config privileged EXEC or show etherchannel channel-group-number detail privileged EXEC command.


Related Commands

Command

Description

channel-group

Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.

show etherchannel

Displays EtherChannel information for a channel.

lacp max-bundle

To define the maximum number of active LACP ports allowed in a port channel, use the lacp max-bundle command in interface configuration mode. To return to the default setting, use the no form of this command.

lacp max-bundle max_bundle_number

no lacp max-bundle

Syntax Description

max_bundle_number

The maximum number of active LACP ports in the port channel. The range is 1 to 8. The default is 8.

Command Default

None

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.3SE

This command was introduced.

Usage Guidelines

An LACP channel group can have up to 16 Ethernet ports of the same type. Up to eight ports can be active, and up to eight ports can be in hot-standby mode. When there are more than eight ports in an LACP channel group, the controller on the controlling end of the link uses port priorities to determine which ports are bundled into the channel and which ports are put in hot-standby mode. Port priorities on the other controller (the noncontrolling end of the link) are ignored.

The lacp max-bundle command must specify a number greater than the number specified by the port-channel min-links command.

Use the show etherchannel summary privileged EXEC command to see which ports are in the hot-standby mode (denoted with an H port-state flag in the output display).

Examples

This example shows how to specify a maximum of five active LACP ports in port channel 2:

Controller(config)# interface port-channel 2 
Controller(config-if)# lacp max-bundle 5


Related Commands

Command

Description

port-channel min-links

Specifies the minimum number of LACP ports that must be in the link-up state and bundled in the EtherChannel in order for the port channel to become active.

lacp port-priority

To configure the port priority for the Link Aggregation Control Protocol (LACP), use the lacp port-priority command in interface configuration mode. To return to the default setting, use the no form of this command.

lacp port-priority priority

no lacp port-priority

Syntax Description

priority

Port priority for LACP. The range is 1 to 65535.

Command Default

The default is 32768.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The lacp port-priority interface configuration command determines which ports are bundled and which ports are put in hot-standby mode when there are more than eight ports in an LACP channel group.

An LACP channel group can have up to 16 Ethernet ports of the same type. Up to eight ports can be active, and up to eight ports can be in standby mode.

In port-priority comparisons, a numerically lower value has a higher priority: When there are more than eight ports in an LACP channel group, the eight ports with the numerically lowest values (highest priority values) for LACP port priority are bundled into the channel group, and the lower-priority ports are put in hot-standby mode. If two or more ports have the same LACP port priority (for example, they are configured with the default setting of 65535), then an internal value for the port number determines the priority.


Note


The LACP port priorities are only effective if the ports are on the controller that controls the LACP link. See the lacp system-priority global configuration command for determining which controller controls the link.


Use the show lacp internal privileged EXEC command to display LACP port priorities and internal port number values.

For information about configuring LACP on physical ports, see the configuration guide for this release.

Examples

This example shows how to configure the LACP port priority on a port:

Controller# interface gigabitethernet2/0/1
Controller(config-if)# lacp port-priority 1000

You can verify your settings by entering the show lacp [channel-group-number] internal privileged EXEC command.


Related Commands

Command

Description

channel-group

Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.

lacp system-priority

Configures the LACP system priority.

show lacp

Displays LACP channel-group information.

lacp system-priority

To configure the system priority for the Link Aggregation Control Protocol (LACP), use the lacp system-priority command in global configuration mode on the controller. To return to the default setting, use the no form of this command.

lacp system-priority priority

no lacp system-priority

Syntax Description

priority

System priority for LACP. The range is 1 to 65535.

Command Default

The default is 32768.

Command Modes

Global configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The lacp system-priority command determines which controller in an LACP link controls port priorities.

An LACP channel group can have up to 16 Ethernet ports of the same type. Up to eight ports can be active, and up to eight ports can be in standby mode. When there are more than eight ports in an LACP channel group, the controller on the controlling end of the link uses port priorities to determine which ports are bundled into the channel and which ports are put in hot-standby mode. Port priorities on the other controller (the noncontrolling end of the link) are ignored.

In priority comparisons, numerically lower values have a higher priority. Therefore, the system with the numerically lower value (higher priority value) for LACP system priority becomes the controlling system. If both controllers have the same LACP system priority (for example, they are both configured with the default setting of 32768), the LACP system ID (the controller MAC address) determines which controller is in control.

The lacp system-priority command applies to all LACP EtherChannels on the controller.

Use the show etherchannel summary privileged EXEC command to see which ports are in the hot-standby mode (denoted with an H port-state flag in the output display).

Examples

This example shows how to set the LACP system priority:

Controller(config)# lacp system-priority 20000

You can verify your settings by entering the show lacp sys-id privileged EXEC command.


Related Commands

Command

Description

channel-group

Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.

lacp port-priority

Configures the port priority for the Link Aggregation Control Protocol (LACP).

show lacp

Displays LACP channel-group information.

pagp learn-method

To learn the source address of incoming packets received from an EtherChannel port, use the pagp learn-method command in interface configuration mode. To return to the default setting, use the no form of this command.

pagp learn-method { aggregation-port | physical-port }

no pagp learn-method

Syntax Description

aggregation-port

Specifies address learning on the logical port channel. The controller sends packets to the source using any port in the EtherChannel. This setting is the default. With aggregation-port learning, it is not important on which physical port the packet arrives.

physical-port

Specifies address learning on the physical port within the EtherChannel. The controller sends packets to the source using the same port in the EtherChannel from which it learned the source address. The other end of the channel uses the same port in the channel for a particular destination MAC or IP address.

Command Default

The default is aggregation-port (logical port channel).

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The learn method must be configured the same at both ends of the link.

The controller supports address learning only on aggregate ports even though the physical-port keyword is provided in the command-line interface (CLI). The pagp learn-method and the pagp port-priority interface configuration commands have no effect on the controller hardware, but they are required for PAgP interoperability with devices that only support address learning by physical ports.

When the link partner to the controller is a physical learner, we recommend that you configure the controller as a physical-port learner by using the pagp learn-method physical-port interface configuration command. We also recommend that you set the load-distribution method based on the source MAC address by using the port-channel load-balance src-mac global configuration command. Use the pagp learn-method interface configuration command only in this situation.

Examples

This example shows how to set the learning method to learn the address on the physical port within the EtherChannel:

Controller(config-if)# pagp learn-method physical-port

This example shows how to set the learning method to learn the address on the port channel within the EtherChannel:

Controller(config-if)# pagp learn-method aggregation-port

You can verify your settings by entering the show running-config privileged EXEC command or the show pagp channel-group-number internal privileged EXEC command.


Related Commands

Command

Description

pagp port-priority

Selects a port over which all traffic through the EtherChannel is sent.

show pagp

Displays Port Aggregation Protocol (PAgP) channel-group information.

pagp port-priority

To select a port over which all Port Aggregation Protocol (PAgP) traffic through the EtherChannel is sent, use the pagp port-priority command in interface configuration mode. If all unused ports in the EtherChannel are in hot-standby mode, they can be placed into operation if the currently selected port and link fails. To return to the default setting, use the no form of this command.

pagp port-priority priority

no pagp port-priority

Syntax Description

priority

Priority number. The range is from 0 to 255.

Command Default

The default is 128.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The physical port with the highest priority that is operational and has membership in the same EtherChannel is the one selected for PAgP transmission.

The controller supports address learning only on aggregate ports even though the physical-port keyword is provided in the command-line interface (CLI). The pagp learn-method and the pagp port-priority interface configuration commands have no effect on the controller hardware, but they are required for PAgP interoperability with devices that only support address learning by physical ports, such as the Catalyst 1900 switch.

When the link partner to the controller is a physical learner, we recommend that you configure the controller as a physical-port learner by using the pagp learn-method physical-port interface configuration command. We also recommend that you set the load-distribution method based on the source MAC address by using the port-channel load-balance src-mac global configuration command. Use the pagp learn-method interface configuration command only in this situation.

Examples

This example shows how to set the port priority to 200:

Controller(config-if)# pagp port-priority 200

You can verify your setting by entering the show running-config privileged EXEC command or the show pagp channel-group-number internal privileged EXEC command.


Related Commands

Command

Description

pagp learn-method

Provides the ability to learn the source address of incoming packets.

port-channel load-balance

Sets the load-distribution method among the ports in the EtherChannel.

show pagp

Displays Port Aggregation Protocol (PAgP) channel-group information.

port-channel load-balance

To set the load-distribution method among the ports in the EtherChannel, use the port-channel load-balance command in global configuration mode. To reset the load-balancing mechanism to the default setting, use the no form of this command.

port-channel load-balance { dst-ip | dst-mac | dst-mixed-ip-port | dst-port | extended | src-dst-ip | src-dst-mac | src-dst-mixed-ip-port | src-dst-port | src-ip | src-mac | src-mixed-ip-port | src-port }

no port-channel load-balance

Syntax Description

dst-ip

Specifies load distribution based on the destination host IP address.

dst-mac

Specifies load distribution based on the destination host MAC address. Packets to the same destination are sent on the same port, but packets to different destinations are sent on different ports in the channel.

dst-mixed-ip-port

Specifies load distribution based on the destination IPv4 or IPv6 address and the TCP/UDP (Layer 4) port number.

dst-port

Specifies load distribution based on the destination TCP/UDP (Layer 4) port number for both IPv4 and IPv6.

extended

Sets extended load balance methods among the ports in the EtherChannel. See the port-channel load-balance extended command.

src-dst-ip

Specifies load distribution based on the source and destination host IP address.

src-dst-mac

Specifies load distribution based on the source and destination host MAC address.

src-dst-mixed-ip-port

Specifies load distribution based on the source and destination host IP address and TCP/UDP (layer 4) port number.

src-dst-port

Specifies load distribution based on the source and destination TCP/UDP (Layer 4) port number.

src-ip

Specifies load distribution based on the source host IP address.

src-mac

Specifies load distribution based on the source MAC address. Packets from different hosts use different ports in the channel, but packets from the same host use the same port.

src-mixed-ip-port

Specifies load distribution based on the source host IP address and TCP/UDP (Layer 4) port number.

src-port

Specifies load distribution based on the TCP/UDP (Layer 4) port number.

Command Default

The default is src-mac.

Command Modes

Global configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

You can verify your setting by entering the show running-config privileged EXEC command or the show etherchannel load-balance privileged EXEC command.

Examples

This example shows how to set the load-distribution method to dst-mac:

Controller(config)# port-channel load-balance dst-mac

port-channel load-balance extended

To set combinations of load-distribution methods among the ports in the EtherChannel, use the port-channel load-balance extended command in global configuration mode. To reset the extended load-balancing mechanism to the default setting, use the no form of this command.

port-channel load-balance extended [ dst-ip | dst-mac | dst-port | ipv6-label | l3-proto | src-ip | src-mac | src-port ]

no port-channel load-balance extended

Syntax Description

dst-ip

(Optional) Specifies load distribution based on the destination host IP address.

dst-mac

(Optional) Specifies load distribution based on the destination host MAC address. Packets to the same destination are sent on the same port, but packets to different destinations are sent on different ports in the channel.

dst-port

(Optional) Specifies load distribution based on the destination TCP/UDP (Layer 4) port number for both IPv4 and IPv6.

ipv6-label

(Optional) Specifies load distribution based on the source MAC address and IPv6 flow label.

l3-proto

(Optional) Specifies load distribution based on the source MAC address and Layer 3 protocols.

src-ip

(Optional) Specifies load distribution based on the source host IP address.

src-mac

(Optional) Specifies load distribution based on the source MAC address. Packets from different hosts use different ports in the channel, but packets from the same host use the same port.

src-port

(Optional) Specifies load distribution based on the TCP/UDP (Layer 4) port number.

Command Default

The default is src-mac.

Command Modes

Global configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

For information about when to use these forwarding methods, see the Layer 2 Configuration Guide (Cisco WLC 5700 Series) for this release.

You can verify your setting by entering the show running-config privileged EXEC command or the show etherchannel load-balance privileged EXEC command.

Examples

This example shows how to set the extended load-distribution method:

Controller(config)# port-channel load-balance extended dst-ip dst-mac src-ip 

port-channel min-links

To define the minimum number of LACP ports that must be bundled in the link-up state and bundled in the EtherChannel in order that a port channel becomes active, use the port-channel min-links command in interface configuration mode. To return to the default setting, use the no form of this command.

port-channel min-links min_links_number

no port-channel min-links

Syntax Description

min_links_number

The minimum number of active LACP ports in the port channel. The range is 2 to 8. The default is 1.

Command Default

None

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.3SE

This command was introduced.

Usage Guidelines

An LACP channel group can have up to 16 Ethernet ports of the same type. Up to eight ports can be active, and up to eight ports can be in hot-standby mode. When there are more than eight ports in an LACP channel group, the controller on the controlling end of the link uses port priorities to determine which ports are bundled into the channel and which ports are put in hot-standby mode. Port priorities on the other controller (the noncontrolling end of the link) are ignored.

The port-channel min-links command must specify a number a less than the number specified by the lacp max-bundle command.

Use the show etherchannel summary privileged EXEC command to see which ports are in the hot-standby mode (denoted with an H port-state flag in the output display).

Examples

This example shows how to specify a minimum of three active LACP ports before port channel 2 becomes active:

Controller(config)# interface port-channel 2 
Controller(config-if)# port-channel min-links 3


Related Commands

Command

Description

lacp max-bundle

Specifies the maximum number of LACP ports allowed in a port channel.

show etherchannel

To display EtherChannel information for a channel, use the show etherchannel command in user EXEC mode.

show etherchannel [ channel-group-number | { detail | port | port-channel | protocol | summary } ] | [ detail | load-balance | port | port-channel | protocol | summary ]

Syntax Description

channel-group-number

(Optional) Channel group number. The range is 1 to 128.

detail

(Optional) Displays detailed EtherChannel information.

load-balance

(Optional) Displays the load-balance or frame-distribution scheme among ports in the port channel.

port

(Optional) Displays EtherChannel port information.

port-channel

(Optional) Displays port-channel information.

protocol

(Optional) Displays the protocol that is being used in the channel.

summary

(Optional) Displays a one-line summary per channel group.

Command Default

None

Command Modes

User EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

If you do not specify a channel group number, all channel groups are displayed.

In the output, the passive port list field is displayed only for Layer 3 port channels. This field means that the physical port, which is still not up, is configured to be in the channel group (and indirectly is in the only port channel in the channel group).

Examples

This is an example of output from the show etherchannel channel-group-number detail command:

Controller> show etherchannel 1 detail
Group state = L2
Ports: 2   Maxports = 16
Port-channels: 1 Max Port-channels = 16
Protocol:      LACP
                   Ports in the group:
                   -------------------
Port: Gi1/0/1
------------
Port state    = Up Mstr In-Bndl
Channel group = 1        Mode  = Active        Gcchange = -
Port-channel  =          Po1GC = -             Pseudo port-channel = Po1
Port index    =          0Load = 0x00          Protocol = LACP

Flags: S - Device is sending Slow LACPDUs   F - Device is sending fast LACPDU
       A - Device is in active mode.        P - Device is in passive mode.

Local information:
                         LACP port   Admin   Oper   Port   Port
Port     Flags   State   Priority    Key     Key    Number State
Gi1/0/1   SA      bndl     32768      0x1     0x1    0x101  0x3D
Gi1/0/2    A      bndl     32768      0x0     0x1    0x0    0x3D

Age of the port in the current state: 01d:20h:06m:04s

                   Port-channels in the group:
                   ----------------------

Port-channel: Po1   (Primary Aggregator)

Age of the Port-channel = 01d:20h:20m:26s
Logical slot/port = 10/1          Number of ports = 2
HotStandBy port   = null
Port state        = Port-channel Ag-Inuse
Protocol          = LACP

Ports in the Port-channel:

Index  Load   Port      EC state        No of bits
------+------+------+------------------+-----------
 0      00    Gi1/0/1    Active           0
 0      00    Gi1/0/2    Active           0

Time since last port bundled:   01d:20h:24m:44s   Gi1/0/2

This is an example of output from the show etherchannel channel-group-number summary command:

Controller> show etherchannel 1 summary
Flags: D - down P - in port-channel
       I - stand-alone s - suspended
       H - Hot-standby (LACP only)
       R - Layer3 S - Layer2
       u - unsuitable for bundling
       U - in use f - failed to allocate aggregator
       d - default port

Number of channel-groups in use: 1
Number of aggregators: 1

Group  Port-channel  Protocol    Ports
------+-------------+-----------+----------------------------------------
 1     Po1(SU)       LACP        Gi1/0/1(P) Gi1/0/2(P)

This is an example of output from the show etherchannel channel-group-number port-channel command:

Controller> show etherchannel 1 port-channel
Port-channels in the group:
----------------------
Port-channel: Po1 (Primary Aggregator)
------------
Age of the Port-channel = 01d:20h:24m:50s
Logical slot/port = 10/1 Number of ports = 2
Logical slot/port = 10/1 Number of ports = 2
Port state = Port-channel Ag-Inuse
Protocol = LACP

Ports in the Port-channel:

Index  Load   Port   EC state           No of bits
------+------+------+------------------+-----------
 0      00    Gi1/0/1 Active             0
 0      00    Gi1/0/2 Active             0

Time since last port bundled: 01d:20h:24m:44s Gi1/0/2

This is an example of output from show etherchannel protocol command:

Controller# show etherchannel protocol
Channel-group listing:
-----------------------
Group: 1
----------
Protocol: LACP
Group: 2
----------
Protocol: PAgP

Related Commands

Command

Description

channel-group

Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.

channel-protocol

Restricts the protocol used on a port to manage channeling.

interface port-channel

Accesses or creates a port channel.

show lacp

To display Link Aggregation Control Protocol (LACP) channel-group information, use the show lacp command in user EXEC mode.

show lacp [ channel-group-number ] { counters | internal | neighbor | sys-id }

Syntax Description

channel-group-number

(Optional) Channel group number. The range is 1 to 128.

counters

Displays traffic information.

internal

Displays internal information.

neighbor

Displays neighbor information.

sys-id

Displays the system identifier that is being used by LACP. The system identifier consists of the LACP system priority and the controller MAC address.

Command Default

None

Command Modes

User EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

You can enter any show lacp command to display the active channel-group information. To display specific channel information, enter the show lacp command with a channel-group number.

If you do not specify a channel group, information for all channel groups appears.

You can enter the channel-group-number to specify a channel group for all keywords except sys-id.

Examples

This is an example of output from the show lacp counters user EXEC command. The table that follows describes the fields in the display.

Controller> show lacp counters
              LACPDUs        Marker     Marker Response   LACPDUs
Port        Sent  Recv     Sent  Recv     Sent  Recv     Pkts  Err
---------------------------------------------------------------------
Channel group:1
Gi2/0/1      19    10        0    0         0    0        0
Gi2/0/2      14    6         0    0         0    0        0


Table 1 show lacp counters Field Descriptions

Field

Description

LACPDUs Sent and Recv

The number of LACP packets sent and received by a port.

Marker Sent and Recv

The number of LACP marker packets sent and received by a port.

Marker Response Sent and Recv

The number of LACP marker response packets sent and received by a port.

LACPDUs Pkts and Err

The number of unknown and illegal packets received by LACP for a port.

This is an example of output from the show lacp internal command:

Controller> show lacp 1 internal
Flags:  S - Device is requesting Slow LACPDUs
        F - Device is requesting Fast LACPDUs
        A - Device is in Active mode       P - Device is in Passive mode

Channel group 1
                           LACP port    Admin    Oper    Port     Port
Port      Flags   State    Priority     Key      Key     Number   State
Gi2/0/1    SA      bndl     32768         0x3     0x3       0x4    0x3D
Gi2/0/2    SA      bndl     32768         0x3     0x3       0x5    0x3D

The following table describes the fields in the display:

Table 2 show lacp internal Field Descriptions

Field

Description

State

State of the specific port. These are the allowed values:

  • —Port is in an unknown state.
  • bndl—Port is attached to an aggregator and bundled with other ports.
  • susp—Port is in a suspended state; it is not attached to any aggregator.
  • hot-sby—Port is in a hot-standby state.
  • indiv—Port is incapable of bundling with any other port.
  • indep—Port is in an independent state (not bundled but able to handle data traffic. In this case, LACP is not running on the partner port).
  • down—Port is down.

LACP Port Priority

Port priority setting. LACP uses the port priority to put ports in standby mode when there is a hardware limitation that prevents all compatible ports from aggregating.

Admin Key

Administrative key assigned to this port. LACP automatically generates an administrative key value as a hexadecimal number. The administrative key defines the ability of a port to aggregate with other ports. A port’s ability to aggregate with other ports is determined by the port physical characteristics (for example, data rate and duplex capability) and configuration restrictions that you establish.

Oper Key

Runtime operational key that is being used by this port. LACP automatically generates this value as a hexadecimal number.

Port Number

Port number.

Port State

State variables for the port, encoded as individual bits within a single octet with these meanings:

  • bit0: LACP_Activity
  • bit1: LACP_Timeout
  • bit2: Aggregation
  • bit3: Synchronization
  • bit4: Collecting
  • bit5: Distributing
  • bit6: Defaulted
  • bit7: Expired
Note   

In the list above, bit7 is the MSB and bit0 is the LSB.

This is an example of output from the show lacp neighbor command:

Controller> show lacp neighbor
Flags: S - Device is sending Slow LACPDUs  F - Device is sending Fast LACPDUs
       A - Device is in Active mode        P - Device is in Passive mode

Channel group 3 neighbors

Partner’s information:

          Partner                Partner               Partner
Port      System ID              Port Number   Age     Flags
Gi2/0/1   32768,0007.eb49.5e80   0xC             19s    SP

          LACP Partner           Partner       Partner
          Port Priority          Oper Key      Port State
          32768                  0x3           0x3C

Partner’s information:

          Partner                Partner               Partner
Port      System ID              Port Number   Age     Flags
Gi2/0/2   32768,0007.eb49.5e80   0xD             15s    SP

          LACP Partner           Partner       Partner
          Port Priority          Oper Key      Port State
          32768                  0x3           0x3C

This is an example of output from the show lacp sys-id command:

Controller> show lacp sys-id
32765,0002.4b29.3a00

The system identification is made up of the system priority and the system MAC address. The first two bytes are the system priority, and the last six bytes are the globally administered individual MAC address associated to the system.


Related Commands

Command

Description

clear lacp

Clears the LACP channel-group information.

lacp port-priority

Configures the port priority for the Link Aggregation Control Protocol (LACP).

lacp system-priority

Configures the LACP system priority.

show pagp

To display Port Aggregation Protocol (PAgP) channel-group information, use the show pagp command in EXEC mode.

show pagp [ channel-group-number ] { counters | dual-active | internal | neighbor }

Syntax Description

channel-group-number

(Optional) Channel group number. The range is 1 to 128.

counters

Displays traffic information.

dual-active

Displays the dual-active status.

internal

Displays internal information.

neighbor

Displays neighbor information.

Command Default

None

Command Modes

User EXEC

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

You can enter any show pagp command to display the active channel-group information. To display the nonactive information, enter the show pagp command with a channel-group number.

Examples

This is an example of output from the show pagp 1 counters command:

Controller> show pagp 1 counters
             Information        Flush
Port         Sent   Recv     Sent   Recv
----------------------------------------
Channel group: 1
  Gi1/0/1    45     42       0      0 
  Gi1/0/2    45     41       0      0 
		

This is an example of output from the show pagp dual-active command:

Controller> show pagp dual-active
PAgP dual-active detection enabled: Yes
PAgP dual-active version: 1.1
		
Channel group 1
          Dual-Active     Partner              Partner   Partner
Port      Detect Capable  Name                 Port      Version
Gi1/0/1   No              Controller               Gi3/0/3   N/A
Gi1/0/2   No              Controller               Gi3/0/4   N/A
		
<output truncated>
		
		

This is an example of output from the show pagp 1 internal command:

Controller> show pagp 1 internal
Flags:  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 1
                                  Hello    Partner  PAgP     Learning  Group
Port        Flags State   Timers  Interval Count   Priority   Method  Ifindex
Gi1/0/1     SC    U6/S7   H       30s      1        128        Any      16
Gi1/0/2     SC    U6/S7   H       30s      1        128        Any      16
		
		

This is an example of output from the show pagp 1 neighbor command:

Controller> show pagp 1 neighbor
		
Flags:  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 neighbors
            Partner              Partner          Partner           Partner Group
Port        Name                 Device ID        Port         Age  Flags   Cap.
Gi1/0/1     controller-p2            0002.4b29.4600   Gi01//1        9s SC      10001 
Gi1/0/2     controller-p2            0002.4b29.4600   Gi1/0/2       24s SC      10001

Related Commands

Command

Description

clear pagp

Clears PAgP channel-group information.

show platform etherchannel

To display platform-dependent EtherChannel information, use the show platform etherchannel command in privileged EXEC mode.

show platform etherchannel channel-group-number { group-mask | load-balance mac src-mac dst-mac [ ip src-ip dst-ip [ port src-port dst-port ] ] }

Syntax Description

channel-group-number

Channel group number. The range is 1 to 128.

group-mask

Displays EtherChannel group mask.

load-balance

Tests EtherChannel load-balance hash algorithm.

mac src-mac dst-mac

Specifies the source and destination MAC addresses.

ip src-ip dst-ip

(Optional) Specifies the source and destination IP addresses.

port src-port dst-port

(Optional) Specifies the source and destination layer port numbers.

Command Default

None

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

Use this command only when you are working directly with a technical support representative while troubleshooting a problem.

Do not use this command unless a technical support representative asks you to do so.

show platform pm

To display platform-dependent port manager information, use the show platform pm command in privileged EXEC mode.

show platform pm { etherchannel channel-group-number group-mask | interface-numbers | port-data interface-id | port-state | spi-info | spi-req-q }

Syntax Description

etherchannel channel-group-number group-mask

Displays the EtherChannel group-mask table for the specified channel group. The range is 1 to 128.

interface-numbers

Displays interface numbers information.

port-data interface-id

Displays port data information for the specified interface.

port-state

Displays port state information.

spi-info

Displays stateful packet inspection (SPI) information.

spi-req-q

Displays stateful packet inspection (SPI) maximum wait time for acknowledgment.

Command Default

None

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

Use this command only when you are working directly with your technical support representative while troubleshooting a problem.

Do not use this command unless your technical support representative asks you to do so.

show udld

To display UniDirectional Link Detection (UDLD) administrative and operational status for all ports or the specified port, use the show udld command in user EXEC mode.

show udld [ Auto-Template | Capwap | GigabitEthernet | GroupVI | InternalInterface | Loopback | Null | Port-channel | TenGigabitEthernet | Tunnel | Vlan] interface_number

show udld neighbors

Syntax Description

Auto-Template

(Optional) Displays UDLD operational status of the auto-template interface. The range is from 1 to 999.

Capwap

(Optional) Displays UDLD operational status of the CAPWAP interface. The range is from 0 to 2147483647.

GigabitEthernet

(Optional) Displays UDLD operational status of the GigabitEthernet interface. The range is from 0 to 9.

GroupVI

(Optional) Displays UDLD operational status of the group virtual interface. The range is from 1 to 255.

InternalInterface

(Optional) Displays UDLD operational status of the internal interface. The range is from 0 to 9.

Loopback

(Optional) Displays UDLD operational status of the loopback interface. The range is from 0 to 2147483647.

Null

(Optional) Displays UDLD operational status of the null interface.

Port-channel

(Optional) Displays UDLD operational status of the Ethernet channel interfaces. The range is from 1 to 128.

TenGigabitEthernet

(Optional) Displays UDLD operational status of the Ten Gigabit Ethernet interface. The range is from 0 to 9.

Tunnel

(Optional) Displays UDLD operational status of the tunnel interface. The range is from 0 to 2147483647.

Vlan

(Optional) Displays UDLD operational status of the VLAN interface. The range is from 1 to 4095.

interface-id

(Optional) ID of the interface and port number. Valid interfaces include physical ports, VLANs, and port channels.

neighbors

(Optional) Displays neighbor information only.

Command Default

None

Command Modes

User EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

If you do not enter an interface ID, administrative and operational UDLD status for all interfaces appear.

Examples

This is an example of output from the show udld interface-id command. For this display, UDLD is enabled on both ends of the link, and UDLD detects that the link is bidirectional. The table that follows describes the fields in this display.

Controller> show udld gigabitethernet2/0/1
Interface gi2/0/1
---
Port enable administrative configuration setting: Follows device default
Port enable operational state: Enabled
Current bidirectional state: Bidirectional
Current operational state: Advertisement - Single Neighbor detected
Message interval: 60
Time out interval: 5
Entry 1
Expiration time: 146
Device ID: 1
Current neighbor state: Bidirectional
Device name: Switch-A
Port ID: Gi2/0/1
Neighbor echo 1 device: Switch-B
Neighbor echo 1 port: Gi2/0/2
Message interval: 5
CDP Device name: Switch-A

Table 3 show udld Field Descriptions

Field

Description

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 current phase of the UDLD state machine. For a normal bidirectional link, the state machine is most often 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 current state. If both the local and neighbor devices are running UDLD normally, the neighbor state and local state should be bidirectional. If the link is down or the neighbor is not UDLD-capable, no cache entries appear.

Device name

The device name or the system serial number of the neighbor. The system serial number appears if the device name is not set or is set to the default (Switch).

Port ID

The neighbor port ID enabled for UDLD.

Neighbor echo 1 device

The device name 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.

CDP device name

The CDP device name or the system serial number. The system serial number appears if the device name is not set or is set to the default (Switch).

This is an example of output from the show udld neighbors command:

Controller# show udld neighbors
Port     Device Name          Device ID  Port-ID  OperState
-------- -------------------- ---------- -------- --------------
Gi2/0/1  Switch-A             1          Gi2/0/1  Bidirectional
Gi3/0/1  Switch-A             2          Gi3/0/1  Bidirectional 


Related Commands

Command

Description

udld

Enables aggressive or normal mode in UDLD or sets the configurable message timer time.

udld port

Enables UDLD on an individual interface or prevents a fiber-optic interface from being enabled by the udld global configuration command.

udld reset

Resets all interfaces shut down by UDLD and permits traffic to pass through again.

switchport

To put an interface that is in Layer 3 mode into Layer 2 mode for Layer 2 configuration, use the switchport command in interface configuration mode. To put an interface in Layer 3 mode, use the no form of this command.

switchport

no switchport

Syntax Description

This command has no arguments or keywords.

Command Default

By default, all interfaces are in Layer 2 mode.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

Use the no switchport command (without parameters) to set the interface to the routed-interface status and to erase all Layer 2 configurations. You must use this command before assigning an IP address to a routed port.


Note


This command is not supported on controllers running the LAN Base feature set.


Entering the no switchport command shuts the port down and then reenables it, which might generate messages on the device to which the port is connected.

When you put an interface that is in Layer 2 mode into Layer 3 mode (or the reverse), the previous configuration information related to the affected interface might be lost, and the interface is returned to its default configuration.


Note


If an interface is configured as a Layer 3 interface, you must first enter the switchport command to configure the interface as a Layer 2 port. Then you can enter the switchport access vlan and switchport mode commands.


The switchport command is not used on platforms that do not support Cisco-routed ports. All physical ports on such platforms are assumed to be Layer 2-switched interfaces.

You can verify the port status of an interface by entering the show running-config privileged EXEC command.

Examples

This example shows how to cause an interface to cease operating as a Layer 2 port and become a Cisco-routed port:

Controller(config-if)# no switchport

This example shows how to cause the port interface to cease operating as a Cisco-routed port and convert to a Layer 2 switched interface:

Controller(config-if)# switchport

switchport access vlan

To configure a port as a static-access port, use the switchport access vlan command in interface configuration mode. To reset the access mode to the default VLAN mode for the controller, use the no form of this command.

switchport access vlan vlan-id

no switchport access vlan

Syntax Description

vlan-id

VLAN ID of the access mode VLAN; the range is 1 to 4094.

Command Default

The default access VLAN and trunk interface native VLAN is a default VLAN corresponding to the platform or interface hardware.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The port must be in access mode before the switchport access vlan command can take effect.

If the switchport mode is set to access vlan vlan-id, the port operates as a member of the specified VLAN. An access port can be assigned to only one VLAN.

The no switchport access command resets the access mode VLAN to the appropriate default VLAN for the device.

Examples

This example shows how to change a switched port interface that is operating in access mode to operate in VLAN 2 instead of the default VLAN:

Controller(config-if)# switchport access vlan 2

Related Commands

Command

Description

switchport mode

Configures the VLAN membership mode of a port.

switchport mode

To configure the VLAN membership mode of a port, use the switchport mode command in interface configuration mode. To reset the mode to the appropriate default for the device, use the no form of this command.

switchport mode { access | dynamic | { auto | desirable } | trunk }

noswitchport mode { access | dynamic | { auto | desirable } | trunk }

Syntax Description

access

Sets the port to access mode (either static-access or dynamic-access depending on the setting of the switchport access vlan interface configuration command). The port is set to access unconditionally and operates as a nontrunking, single VLAN interface that sends and receives nonencapsulated (non-tagged) frames. An access port can be assigned to only one VLAN.

dynamic auto

Sets the port trunking mode dynamic parameter to auto to specify that the interface convert the link to a trunk link. This is the default switchport mode.

dynamic desirable

Sets the port trunking mode dynamic parameter to desirable to specify that the interface actively attempt to convert the link to a trunk link.

trunk

Sets the port to trunk unconditionally. The port is a trunking VLAN Layer 2 interface. The port sends and receives encapsulated (tagged) frames that identify the VLAN of origination. A trunk is a point-to-point link between two controllers or between a controller and a router.

Command Default

The default mode is dynamic auto.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines


Note


Although visible in the CLI, the dot1q-tunnel keyword is not supported.

A configuration that uses the access,or trunk keywords takes effect only when you configure the port in the appropriate mode by using the switchport mode command. The static-access and trunk configuration are saved, but only one configuration is active at a time.

When you enter access mode, the interface changes to permanent nontrunking mode and negotiates to convert the link into a nontrunk link even if the neighboring interface does not agree to the change.

When you enter trunk mode, the interface changes to 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.

When 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.

When you enter dynamic desirable mode, the interface becomes a trunk interface if the neighboring interface is set to trunk, desirable, or auto mode.

To autonegotiate trunking, the interfaces must be in the same VLAN Trunking Protocol (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 problem, configure interfaces connected to devices that do not support DTP to not forward DTP frames, which turns off DTP.

  • If you do not intend to trunk across those links, use the switchport mode access interface configuration command to disable trunking.
  • To enable trunking to a device that does not support DTP, use the switchport mode trunk and switchport nonegotiate interface configuration commands to cause the interface to become a trunk but to not generate DTP frames.

Access ports and trunk ports are mutually exclusive.

The IEEE 802.1x feature interacts with switchport modes in these ways:

  • If you try to enable IEEE 802.1x on a trunk port, an error message appears, and IEEE 802.1x is not enabled. If you try to change the mode of an IEEE 802.1x-enabled port to trunk, the port mode is not changed.
  • If you try to enable IEEE 802.1x on a port set to dynamic auto or dynamic desirable, an error message appears, and IEEE 802.1x is not enabled. If you try to change the mode of an IEEE 802.1x-enabled port to dynamic auto or dynamic desirable, the port mode is not changed.
  • If you try to enable IEEE 802.1x on a dynamic-access (VLAN Query Protocol [VQP]) port, an error message appears, and IEEE 802.1x is not enabled. If you try to change an IEEE 802.1x-enabled port to dynamic VLAN assignment, an error message appears, and the VLAN configuration is not changed.

You 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.

Examples

This example shows how to configure a port for access mode:

Controller(config)# interface gigabitethernet2/0/1
Controller(config-if)# switchport mode access

This example shows how set the port to dynamic desirable mode:

Controller(config)# interface gigabitethernet2/0/1
Controller(config-if)# switchport mode dynamic desirable   

This example shows how to configure a port for trunk mode:

Controller(config)# interface gigabitethernet2/0/1
Controller(config-if)# switchport mode trunk


Related Commands

Command

Description

switchport access vlan

Configures a port as a static-access port.

switchport nonegotiate

To specify that Dynamic Trunking Protocol (DTP) negotiation packets are not sent on the Layer 2 interface, use the switchport nonegotiate command in interface configuration mode. 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.

Command Default

The default is to use DTP negotiation to learn the trunking status.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

The no 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 problem, turn off DTP by using the switchport nonegotiate 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: access or trunk.

  • If you do not intend to trunk across those links, use the switchport mode access interface configuration command to disable trunking.
  • To enable trunking on a device that does not support DTP, use the switchport mode trunk and switchport nonegotiate interface configuration commands to cause the interface to become a trunk but to not generate DTP frames.

Examples

This example shows how to cause a port to refrain from negotiating trunking mode and to act as a trunk or access port (depending on the mode set):

Controller(config)# interface gigabitethernet2/0/1
Controller(config-if)# switchport nonegotiate

You can verify your setting by entering the show interfaces interface-id switchport privileged EXEC command.


Related Commands

Command

Description

switchport mode

Configures the VLAN membership mode of a port.

udld

To enable aggressive or normal mode in the UniDirectional Link Detection (UDLD) and to set the configurable message timer time, use the udld command in global configuration mode. To disable aggressive or normal mode UDLD on all fiber-optic ports, use the no form of the command.

udld { aggressive | enable | message time message-timer-interval }

no udld { aggressive | enable | message }

Syntax Description

aggressive

Enables UDLD in aggressive mode on all fiber-optic interfaces.

enable

Enables UDLD in normal mode on all fiber-optic interfaces.

message time message-timer-interval

Configures the period of time between UDLD probe messages on ports that are in the advertisement phase and are determined to be bidirectional. The range is 1 to 90 seconds. The default is 15 seconds.

Command Default

UDLD is disabled on all interfaces.

The message timer is set at 15 seconds.

Command Modes

Global configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

UDLD supports two modes of operation: normal (the default) and aggressive. In normal mode, UDLD detects unidirectional links due to misconnected interfaces on fiber-optic connections. In aggressive mode, UDLD also detects unidirectional links due to one-way traffic on fiber-optic and twisted-pair links and due to misconnected interfaces on fiber-optic links. For information about normal and aggressive modes, see the Catalyst 2960-X Switch Layer 2 Configuration GuideCatalyst 2960-XR Switch Layer 2 Configuration GuideLayer 2 Configuration Guide (Cisco WLC 5700 Series).

If you change the message time between probe packets, you are making a compromise between the detection speed and the CPU load. By decreasing the time, you can make the detection-response faster but increase the load on the CPU.

This command affects fiber-optic interfaces only. Use the udld interface configuration command to enable UDLD on other interface types.

You can use these commands to reset an interface shut down by UDLD:

  • The udld reset privileged EXEC command to reset all interfaces shut down by UDLD.
  • The shutdown and no shutdown interface configuration commands.
  • The no udld enable global configuration command followed by the udld {aggressive | enable} global configuration command to reenable UDLD globally.
  • The no udld port interface configuration command followed by the udld port or udld port aggressive interface configuration command to reenable UDLD on the specified interface.
  • The errdisable recovery cause udld and errdisable recovery interval interval global configuration commands to automatically recover from the UDLD error-disabled state.

Examples

This example shows how to enable UDLD on all fiber-optic interfaces:

Controller(config)# udld enable

You can verify your setting by entering the show udld privileged EXEC command.


Related Commands

Command

Description

show udld

Displays UDLD administrative and operational status for all ports or the specified port.

udld port

Enables UDLD on an individual interface or prevents a fiber-optic interface from being enabled by the udld global configuration command.

udld reset

Resets all interfaces shut down by UDLD and permits traffic to pass through again.

udld port

To enable UniDirectional Link Detection (UDLD) on an individual interface or to prevent a fiber-optic interface from being enabled by the udld global configuration command, use the udld port command in interface configuration mode. To return to the udld global configuration command setting or to disable UDLD if entered for a nonfiber-optic port, use the no form of this command.

udld port [aggressive]

no udld port [aggressive]

Syntax Description

aggressive

(Optional) Enables UDLD in aggressive mode on the specified interface.

Command Default

On fiber-optic interfaces, UDLD is disabled and fiber-optic interfaces enable UDLD according to the state of the udld enable or udld aggressive global configuration command.

On nonfiber-optic interfaces, UDLD is disabled.

Command Modes

Interface configuration

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of another controller.

UDLD supports two modes of operation: normal (the default) and aggressive. In normal mode, UDLD detects unidirectional links due to misconnected interfaces on fiber-optic connections. In aggressive mode, UDLD also detects unidirectional links due to one-way traffic on fiber-optic and twisted-pair links and due to misconnected interfaces on fiber-optic links.

To enable UDLD in normal mode, use the udld port interface configuration command. To enable UDLD in aggressive mode, use the udld port aggressive interface configuration command.

Use the no udld port command on fiber-optic ports to return control of UDLD to the udld enable global configuration command or to disable UDLD on nonfiber-optic ports.

Use the udld port aggressive command on fiber-optic ports to override the setting of the udld enable or udld aggressive global configuration command. Use the no form on fiber-optic ports to remove this setting and to return control of UDLD enabling to the udld global configuration command or to disable UDLD on nonfiber-optic ports.

You can use these commands to reset an interface shut down by UDLD:

  • The udld reset privileged EXEC command resets all interfaces shut down by UDLD.
  • The shutdown and no shutdown interface configuration commands.
  • The no udld enable global configuration command, followed by the udld {aggressive | enable} global configuration command reenables UDLD globally.
  • The no udld port interface configuration command, followed by the udld port or udld port aggressive interface configuration command reenables UDLD on the specified interface.
  • The errdisable recovery cause udld and errdisable recovery interval interval global configuration commands automatically recover from the UDLD error-disabled state.

Examples

This example shows how to enable UDLD on an port:

Controller(config)# interface gigabitethernet6/0/1
Controller(config-if)# udld port

This example shows how to disable UDLD on a fiber-optic interface despite the setting of the udld global configuration command:

Controller(config)# interface gigabitethernet6/0/1
Controller(config-if)# no udld port

You can verify your settings by entering the show running-config or the show udld interface privileged EXEC command.


Related Commands

Command

Description

show udld

Displays UDLD administrative and operational status for all ports or the specified port.

udld

Enables aggressive or normal mode in UDLD or sets the configurable message timer time.

udld reset

Resets all interfaces shut down by UDLD and permits traffic to pass through again.

udld reset

To reset all interfaces disabled by UniDirectional Link Detection (UDLD) and permit traffic to begin passing through them again (though other features, such as spanning tree, Port Aggregation Protocol (PAgP), and Dynamic Trunking Protocol (DTP) still have their normal effects, if enabled), use the udld reset command in privileged EXEC mode.

udld reset

Syntax Description

This command has no arguments or keywords.

Command Default

None

Command Modes

Privileged EXEC

Command History

Release

Modification

Cisco IOS XE 3.2SE

This command was introduced.

Usage Guidelines

If the interface configuration is still enabled for UDLD, these ports begin to run UDLD again and are disabled for the same reason if the problem has not been corrected.

Examples

This example shows how to reset all interfaces disabled by UDLD:

Controller# udld reset
1 ports shutdown by UDLD were reset.

Related Commands

Command

Description

show udld

Displays UDLD administrative and operational status for all ports or the specified port.

udld

Enables aggressive or normal mode in UDLD or sets the configurable message timer time.

udld port

Enables UDLD on an individual interface or prevents a fiber-optic interface from being enabled by the udld global configuration command.