Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 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 1-6 on page 1-24 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 1-4 Commands for Displaying EtherChannel, PAgP, and LACP Status (continued)
Command Description