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Layer 2/3 Commands
channel-group
To assign an Ethernet port to an EtherChannel group, to enable an EtherChannel mode, or both, use the channel-group command in interface configuration mode on the switch stack or on a standalone switch. 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 switch interface for nonsilent operation when the switch is 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 History
Usage Guidelines
For Layer 2 EtherChannels, you do not have to create a port-channel interface by using the interface port-channel global configuration command before assigning a physical port to a channel group. Instead, you can use the channel-group interface configuration command. This automatically creates the port-channel interface when the channel group gets its first physical port if the logical interface is not already created. 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 do not have to disable the IP address that is assigned to a physical port that is part of a channel group, but 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. You should 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 switch is connected to a device that is not PAgP-capable and seldom, if ever, sends packets. A 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.
CautionYou should 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 switch or on different switch 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 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.
CautionDo 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 switch in the stack. It assigns two static-access ports in VLAN 10 to channel 5 with the PAgP mode desirable:
Switch# configure terminal Switch(config)# interface range gigabitethernet2/0/1 -2 Switch(config-if-range)# switchport mode access Switch(config-if-range)# switchport access vlan 10 Switch(config-if-range)# channel-group 5 mode desirable Switch(config-if-range)# endThis example shows how to configure an EtherChannel on a single switch in the stack. It assigns two static-access ports in VLAN 10 to channel 5 with the LACP mode active:
Switch# configure terminal Switch(config)# interface range gigabitethernet2/0/1 -2 Switch(config-if-range)# switchport mode access Switch(config-if-range)# switchport access vlan 10 Switch(config-if-range)# channel-group 5 mode active Switch(config-if-range)# endThis example shows how to configure a cross-stack EtherChannel in a switch 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:
Switch# configure terminal Switch(config)# interface range gigabitethernet2/0/4 -5 Switch(config-if-range)# switchport mode access Switch(config-if-range)# switchport access vlan 10 Switch(config-if-range)# channel-group 5 mode passive Switch(config-if-range)# exit Switch(config)# interface gigabitethernet3/0/3 Switch(config-if)# switchport mode access Switch(config-if)# switchport access vlan 10 Switch(config-if)# channel-group 5 mode passive Switch(config-if)# exitYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
Command
Description
Restricts the protocol used on a port to manage channeling.
Accesses or creates the port channel.
Displays EtherChannel information for a channel.
Displays LACP channel-group information.
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 on the switch stack or on a standalone switch. To return to the default setting, use the no form of this command.
Syntax Description
lacp Configures an EtherChannel with the Link Aggregation Control Protocol (LACP).
pagp Configures an EtherChannel with the Port Aggregation Protocol (PAgP).
Command History
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.
Related Commands
Command
Description
Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.
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 on the switch stack or on a standalone switch.
Syntax Description
channel-group-number (Optional) Channel group number. The range is 1 to 128.
counters Clears traffic counters.
Command History
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:
Switch# clear lacp countersThis example shows how to clear LACP traffic counters for group 4:
Switch# clear lacp 4 countersYou 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
Displays LACP channel-group information.
clear pagp
To clear Port Aggregation Protocol (PAgP) channel-group information, use the clear pagp command in privileged EXEC mode on the switch stack or on a standalone switch.
Syntax Description
channel-group-number (Optional) Channel group number. The range is 1 to 128.
counters Clears traffic counters.
Command History
Related Commands
Command
Description
Displays Port Aggregation Protocol (PAgP) channel-group information.
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.
ses
Displays service expansion shelf (SES) related event debug messages.
vlans
Displays VLAN creation and deletion event debug messages.
Command History
Usage Guidelines
The undebug platform pm command is the same as the no debug platform pm command.
When you enable debugging on a switch stack, it is enabled only on the active switch. To enable debugging on a stack member, you can start a session from the active switch by using the session switch-number EXEC command. Then enter the debug command at the command-line prompt of the stack member.
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 History
Usage Guidelines
The undebug platform udld command is the same as the no debug platform udld command.
When you enable debugging on a switch stack, it is enabled only on the active switch. To enable debugging on a stack member, you can start a session from the active switch by using the session switch-number EXEC command. Then enter the debug command at the command-line prompt of the stack member.
interface port-channel
To access or create the port-channel logical interface, use the interface port-channel command in global configuration mode on the switch stack or on a standalone switch. Use the no form of this command to remove the port channel.
Syntax Description
Command History
Usage Guidelines
For Layer 2 EtherChannels, you do not have to create a port-channel interface first before assigning a physical port to a channel group. Instead, you can use the channel-group interface configuration command. It automatically creates the port-channel interface when the channel group gets 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.
CautionWhen 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.
CautionDo 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 only 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.
Related Commands
Command
Description
Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.
Displays EtherChannel information for a channel.
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 on the switch stack or on a standalone switch. To return to the default setting, use the no form of this command.
Syntax Description
Command History
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) an internal value for the port number determines the priority.
NoteThe LACP port priorities are only effective if the ports are on the switch that controls the LACP link. See the lacp system-priority global configuration command for determining which switch 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.
Related Commands
Command
Description
Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.
Configures the LACP system priority.
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 switch stack or on a standalone switch. To return to the default setting, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
The lacp system-priority command determines which switch 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 switch 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 switch (the noncontrolling end of the link) are ignored.
In priority comparisons, numerically lower values have higher priority. Therefore, the system with the numerically lower value (higher priority value) for LACP system priority becomes the controlling system. If both switches have the same LACP system priority (for example, they are both configured with the default setting of 32768), the LACP system ID (the switch MAC address) determines which switch is in control.
The lacp system-priority command applies to all LACP EtherChannels on the switch.
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).
For more information about configuring LACP on physical ports, see the software configuration guide for this release.
Related Commands
Command
Description
Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.
Configures the port priority for the Link Aggregation Control Protocol (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 on the switch stack or on a standalone switch. To return to the default setting, use the no form of this command.
Syntax Description
aggregation-port Specifies address learning on the logical port channel. The switch sends packets to the source using any of the ports in the EtherChannel. This setting is the default. With aggregate-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 switch 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 History
Usage Guidelines
The learn method must be configured the same at both ends of the link.
The switch 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 switch 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 switch is a physical learner, we recommend that you configure the switch as a physical-port learner by using the pagp learn-method physical-port interface configuration command and to 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:
Switch(config-if)# pagp learn-method physical-portThis example shows how to set the learning method to learn the address on the port channel within the EtherChannel:
Switch(config-if)# pagp learn-method aggregation-portYou 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
Selects a port over which all traffic through the EtherChannel is sent.
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 on the switch stack or on a standalone switch. 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.
Syntax Description
Command History
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 switch 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 switch 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 switch is a physical learner, we recommend that you configure the switch as a physical-port learner by using the pagp learn-method physical-port interface configuration command and to 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.
Related Commands
Command
Description
Provides the ability to learn the source address of incoming packets.
Sets the load-distribution method among the ports in the EtherChannel.
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 History
Usage Guidelines
For information about when to use these forwarding methods, see the software configuration guide 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.
Related Commands
Command
Description
Sets extended load-distribution methods among the ports in the EtherChannel.
port-channel load-balance extended
To set extended 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 History
Usage Guidelines
For information about when to use these forwarding methods, see the Layer 2/3 Configuration Guide (Catalyst 3850 Switches) 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.
Related Commands
Command
Description
Sets the load-distribution method among the ports in the EtherChannel.
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 Displays detailed EtherChannel information.
load-balance Displays the load-balance or frame-distribution scheme among ports in the port channel.
port Displays EtherChannel port information.
port-channel Displays port-channel information.
protocol Displays the protocol that is being used in the channel.
summary Displays a one-line summary per channel group.
Command History
Usage Guidelines
If you do not specify a channel-group, 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).
NoteLayer 3 port channels are not supported when the switch is running the LAN Base feature set.
Examples
This is an example of output from the show etherchannel channel-group-number detail command:
Switch> 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 Gi1/0/2This is an example of output from the show etherchannel channel-group-number summary command:
Switch> 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:
Switch> 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 Gi1/0/2This is an example of output from show etherchannel protocol command:
Switch# show etherchannel protocol Channel-group listing: ----------------------- Group: 1 ---------- Protocol: LACP Group: 2 ---------- Protocol: PAgP
Related Commands
Command
Description
Assigns an Ethernet port to an EtherChannel group, or enables an EtherChannel mode, or both.
Restricts the protocol used on a port to manage channeling.
Accesses or creates the port channel.
show lacp
To display Link Aggregation Control Protocol (LACP) channel-group information, use the show lacp command in user EXEC mode.
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 is made up of the LACP system priority and the switch MAC address.
Command History
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.
Switch> 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:
Switch> 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 0x3DThe following table describes the fields in the display:
This is an example of output from the show lacp neighbor command:
Switch> 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 0x3CThis is an example of output from the show lacp sys-id command:
Switch> show lacp sys-id 32765,0002.4b29.3a00The 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
Clears the LACP channel-group information.
Configures the port priority for the Link Aggregation Control Protocol (LACP).
Configures the LACP system priority.
show pagp
To display Port Aggregation Protocol (PAgP) channel-group information, use the show pagp command in EXEC mode.
Syntax Description
channel-group-number
(Optional) Number of the channel group. 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 History
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:
Switch> 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 0This is an example of output from the show pagp dual-active command:
Switch> 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 Switch Gi3/0/3 N/A Gi1/0/2 No Switch Gi3/0/4 N/A <output truncated>This is an example of output from the show pagp 1 internal command:
Switch> 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 16This is an example of output from the show pagp 1 neighbor command:
Switch> 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 switch-p2 0002.4b29.4600 Gi01//1 9s SC 10001 Gi1/0/2 switch-p2 0002.4b29.4600 Gi1/0/2 24s SC 10001
Related Commands
Command
Description
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 ] ] } [ switch switch-number ]
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.
switch switch-number
(Optional) Specifies the stack member.
Command History
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 channel-group 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 History
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.
Syntax Description
interface-id (Optional) ID of the interface and port number. Valid interfaces include physical ports and VLANs. The VLAN range is 1 to 4094.
neighbors (Optional) Displays neighbor information only.
Command History
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.
Switch> 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:
Switch# 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
Enables aggressive or normal mode in UDLD or sets the configurable message timer time.
Enables UDLD on an individual interface or prevents a fiber-optic interface from being enabled by the udld global configuration command.
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.
Command History
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.
NoteThis command is not supported on switches 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 switch 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:
Switch(config-if)# no switchportThis example shows how to cause the port interface to cease operating as a Cisco-routed port and convert to a Layer 2 switched interface:
Switch(config-if)# switchportswitchport access vlan
To configure a port as a static-access, use the switchport access vlan command in interface configuration mode. To reset the access mode to the default VLAN mode for the switch, use the no form of this command.
Syntax Description
Command Default
The default access VLAN and trunk interface native VLAN is a default VLAN corresponding to the platform or interface hardware.
Command History
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.
Related Commands
Command
Description
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 | dot1q-tunnel | dynamic { auto | desirable } | trunk }
no switchport mode { access | dot1q-tunnel | dynamic | 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.
dot1q-tunnel
Sets the port as an IEEE 802.1Q tunnel port.
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 switches or between a switch and a router.
Command History
Usage Guidelines
A configuration that uses the access, dot1q-tunnel, 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, you should 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.
When you enter dot1q-tunnel, the port is set unconditionally as an IEEE 802.1Q tunnel port.
Access ports, trunk ports, and tunnel ports are mutually exclusive.
Any IEEE 802.1Q encapsulated IP packets received on a tunnel port can be filtered by MAC access control lists (ACLs), but not by IP ACLs. This is because the switch does not recognize the protocol inside the IEEE 802.1Q header. This restriction applies to router ACLs, port ACLs, and VLAN maps.
Configuring a port as an IEEE 802.1Q tunnel port has these limitations:
- IP routing is not supported on tunnel ports.
- Tunnel ports do not support IP ACLs.
- If an IP ACL is applied to a trunk port in a VLAN that includes tunnel ports, or if a VLAN map is applied to a VLAN that includes tunnel ports, packets received from the tunnel port are treated as non-IP packets and are filtered with MAC access lists.
- Layer 3 quality of service (QoS) ACLs and other QoS features related to Layer 3 information are not supported on tunnel ports.
For more information about configuring IEEE 802.1Q tunnel ports, see the software configuration guide for this release.
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:
Switch(config)# interface gigabitethernet2/0/1 Switch(config-if)# switchport mode accessThis example shows how set the port to dynamic desirable mode:
Switch(config)# interface gigabitethernet2/0/1 Switch(config-if)# switchport mode dynamic desirableThis example shows how to configure a port for trunk mode:
Switch(config)# interface gigabitethernet2/0/1 Switch(config-if)# switchport mode trunkThis example shows how to configure a port as an IEEE 802.1Q tunnel port:
Switch(config)# interface gigabitethernet2/0/1 Switch(config-if)# switchport mode dot1q-tunnel
Related Commands
Command
Description
Configures a port as a static-access or dynamic-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 on the switch stack or on a standalone switch. The switch does not engage in DTP negotiation on this interface. Use the no form of this command to return to the default setting.
Command History
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, you should 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):
Switch(config)# interface gigabitethernet2/0/1 Switch(config-if)# switchport nonegotiateYou can verify your setting by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
Command
Description
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 on the switch stack or on a standalone switch. 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 History
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 Layer 2/3 Configuration Guide (Catalyst 3850 Switches).
If you change the message time between probe packets, you are making a trade-off 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.
Related Commands
Command
Description
Displays UDLD administrative and operational status for all ports or the specified port.
Enables UDLD on an individual interface or prevents a fiber-optic interface from being enabled by the udld global configuration command.
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 prevent a fiber-optic interface from being enabled by the udld global configuration command, use the udld port command in interface configuration mode on the switch stack or on a standalone switch. 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.
Syntax Description
Command Default
On fiber-optic interfaces, UDLD is not enabled, not in aggressive mode, and not disabled. For this reason, 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 History
Usage Guidelines
A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of another switch.
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 Layer 2/3 Configuration Guide (Catalyst 3850 Switches).
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:
Switch(config)# interface gigabitethernet6/0/1 Switch(config-if)# udld portThis example shows how to disable UDLD on a fiber-optic interface despite the setting of the udld global configuration command:
Switch(config)# interface gigabitethernet6/0/1 Switch(config-if)# no udld portYou can verify your settings by entering the show running-config or the show udld interface privileged EXEC command.
Related Commands
Command
Description
Displays UDLD administrative and operational status for all ports or the specified port.
Enables aggressive or normal mode in UDLD or sets the configurable message timer time.
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.
Command History
Related Commands
Command
Description
Displays UDLD administrative and operational status for all ports or the specified port.
Enables aggressive or normal mode in UDLD or sets the configurable message timer time.
Enables UDLD on an individual interface or prevents a fiber-optic interface from being enabled by the udld global configuration command.
