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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 22 Configuring EtherChannel and Link State Tracking
Configuring Link-State Tracking
Configuring Link-State Tracking
These sections describe how to configure link-state tracking ports:
• Default Link-State Tracking Configuration, page 22-21
• Link-State Tracking Configuration Guidelines, page 22-21
• Configuring Link-State Tracking, page 22-21
• Displaying Link-State Tracking Status, page 22-22
Default Link-State Tracking Configuration
No link-state groups are defined, and link-state tracking is not enabled for any group.
Link-State Tracking Configuration Guidelines
Follow these guidelines to avoid configuration problems:
• An interface that is defined as an upstream interface cannot also be defined as a downstream
interface in the same or different link-state group. The reverse is also true.
• We recommend that you add the upstream interfaces to the link state group before adding the
downstream interfaces. it is because when a downstream interface is added to a link state group
without an upstream interface, the downstream interface is put in error-disabled state until an
upstream interfaces is added to the group.
• An interface cannot be a member of more than one link-state group.
• You can configure up to ten link-state groups per switch.
• If a SPAN destination port is configured as a downstream interface, it is error disabled when all
upstream interfaces in its group are down. When an upstream interface is configured as a SPAN
destination port, it is considered as a link down event on the interface.
Configuring Link-State Tracking
To configure a link-state group and to assign an interface to a group, perform this task beginning in
privileged EXEC mode:
Command Purpose
Step 1
Switch# configure terminal
Enters global configuration mode.
Step 2
Switch(config)# link state track number
Creates a link-state group, and enable link-state tracking. The
group number can be 1 to 10; the default is 1.
Step 3
Switch(config)# interface interface-id
Specifies a physical interface or range of interfaces to configure,
and enters interface configuration mode.
Valid interfaces include switch ports in access or trunk mode
(IEEE 802.1q), routed ports, or multiple ports bundled into an
EtherChannel interface (static or LACP), also in trunk mode.