40-23
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 40 Configuring EtherChannels and Link-State Tracking Understanding Link-State Tracking
You can clear PAgP channel-group information and traffic counters by using the clear pagp
{channel-group-number counters | counters} privileged EXEC command.
You can clear LACP channel-group information and traffic counters by using the clear lacp
{channel-group-number counters | counters} privileged EXEC command.
For detailed information about the fields in the displays, see the command reference for this release.
Understanding Link-State Tracking
Link-state tracking, also known as trunk failover, is a feature that binds the link state of multiple
interfaces. Link-state tracking provides redundancy in the network when used with server network
interface card (NIC) adapter teaming. When the server network adapters are configured in a primary or
secondary relationship known as teaming and the link is lost on the primary interface, connectivity
transparently changes to the secondary interface.
Figure 40-6 on page 40-24 shows a network configured with link-state tracking. To enable link-state
tracking, create a link-state group, and specify the interfaces that are assigned to the link-state group. An
interface can be an aggregation of ports (an EtherChannel), a single physical port in access or trunk
mode, or a routed port. In a link-state group, these interfaces are bundled together. The downstream
interfaces are bound to the upstream interfaces. Interfaces connected to servers are referred to as
downstream interfaces, and interfaces connected to distribution switches and network devices are
referred to as upstream interfaces.
show pagp [channel-group-number] dual-active Displays the dual-active detection status.
show lacp [channel-group-number] {counters |
internal | neighbor}
Displays LACP information such as traffic information, the
internal LACP configuration, and neighbor information.
Table 40-4 Commands for Displaying EtherChannel, PAgP, and LACP Status (continued)
Command Description