link-keepalive ethernet

Enables UDLD for tagged and untagged control packets.
Syntax
link-keepalive ethernet { unit/slot/port } [ to unit/slot/port [ ethernet unit/slot/port [ to unit/slot/port ] ... ] [ vlan vlan-ID ]
no link-keepalive ethernet { unit/slot/port } [ to unit/slot/port [ ethernet unit/slot/port [ to unit/slot/port ] ... ] [ vlan vlan-ID ]
Command Default

UDLD is not enabled.

Parameters
ethernet unit/slot/port
Specifies the Ethernet interface on which to enable UDLD.
to unit/slot/port
Specifies a range of Ethernet interfaces on which to enable UDLD.
vlan vlan-ID
Specifies the ID of the VLAN that the UDLD control packets can contain.
Modes

Global configuration mode

Usage Guidelines

UDLD is supported only on Ethernet ports.

The command cannot support LAG virtual interfaces. Attempting to configure them will have no effect.

If you are specifying a VLAN ID, make sure that the VLAN ID is configured. A VLAN is specified when UDLD is configured. The port belongs to the configured VLAN as a tagged member. All the devices across the UDLD link are in the same VLAN. UDLD can be enabled on only one VLAN for a tagged port.

You must configure the same VLANs that will be used for UDLD on all devices across the network; otherwise, the UDLD link cannot be maintained.

You can specify a list of Ethernet ports, separated by a space, or a range of ports, or you can combine lists and ranges.

The no form of the command disables UDLD for tagged and untagged control packets.

Examples

The following example shows how to enable UDLD for untagged ports.

device(config)# link-keepalive ethernet 1/1/1

The following example shows how to configure UDLD on multiple ports.

device(config)# link-keepalive ethernet 1/1/1 ethernet 1/2/2

The following example shows how to configure UDLD on a range of ports.

device(config)# link-keepalive ethernet 1/1/1 to 1/1/5

The following example enables ports to receive and send UDLD control packets tagged with a specific VLAN ID.

device(config)# link-keepalive ethernet 1/1/8 vlan 22