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Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02
Chapter37 Configuring EtherChann els and Link-State Tracking
Displaying EtherChannel, PAgP, and LACP Status
Displaying EtherChannel, PAgP, and LACP Status
To display EtherChannel, PAgP, and LACP status information, use the privileged EXEC commands
described in Tabl e 37-4:
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. For example, link-state tracking provides redundancy in the network when used with server
NIC adapter teaming. When the server network adapters are configured in a primary or seconda ry
relationship known as teaming, if the link is lost on the primary interface, connectivity is transparently
switched to the secondary interface.
As shown in Figure37-6, server 1 and server 2 use switch A for primary links and switch B for seco ndary
links to switches and other network devices. Server 3 and server 4 use switch B for primary links and
switch A for secondary links. This configuration ensures that the traffic flow is balanced in the network.
Ports connected to servers are referred to as downstream ports, and ports connected to distribution
switches and network devices are referred to as upstream ports.
•Switch A provides primary links to server 1 and server 2 through link-stat e group 1. Port 1 is
connected to server 1, and port 2 is connected to server 2. Po rt 3 and port 4 on switch A also provide
secondary links through link-state group 2. Port 5 and port 6 are connecte d to distribution switch 1
through link-state group 1, and port 7 and port 8 are also connected to distribution switch 2 through
link-state group 2.
•Switch B provides primary links to server 3 and sever 4 through link-state group 2 and secondary
links to server 1 and server 2 through link-state group 1. Port 3 and port 4 are connected to server 3
and server 4 through the primary links in link-state group 1 . Port 1 and port 2 are connected to
server 1 and server 2 through secondary links in link-state group 2. Port 5 and port 6 ar e connected
to distribution switch 2 through link-state group 2; port 7 and port 8 are connected to distribution
switch 1 through link-state group 1.
Table37-4 Commands for Displaying EtherChannel, PAgP, and LACP Status
Command Description
show etherchannel [channel-group-number {detail |
port | port-channel | protocol | summary}] {detail |
load-balance | port | port-channel | protocol |
summary}
Displays EtherChannel information in a brief, detailed, and
one-line summary form. Also displays the load-balance or
frame-distribution scheme, port, port-channel, and protocol
information.
show pagp [channel-group-number] {counters |
internal | neighbor}
Displays PAgP information such as traffic information, the
internal PAgP configuration, and neighbor information.
show lacp [channel-group-number] {counters |
internal | neighbor}
Displays LACP information such as traffic information, the
internal LACP configuration, and neighbor information.