Reference Guide

To view the PDU exchanges and the timeout value, use the debug lacp command. For more information, refer to

Monitoring and Debugging LACP.

Monitoring and Debugging LACP

The system log (syslog) records faulty LACP actions.

To debug LACP, use the following command.

• Debug LACP, including configuration and events.

EXEC mode

Shared LAG State Tracking

Shared LAG state tracking provides the flexibility to bring down a port channel (LAG) based on the operational state of

another LAG.

At any time, only two LAGs can be a part of a group such that the fate (status) of one LAG depends on the other LAG.

As shown in the following illustration, the line-rate traffic from R1 destined for R4 follows the lowest-cost route via R2.

Traffic is equally distributed between LAGs 1 and 2. If LAG 1 fails, all traffic from R1 to R4 flows across LAG 2 only. This

condition over-subscribes the link and packets are dropped.

Figure 46. Shared LAG State Tracking

To avoid packet loss, redirect traffic through the next lowest-cost link (R3 to R4). FTOS has the ability to bring LAG 2

down if LAG 1 fails, so that traffic can be redirected. This redirection is what is meant by shared LAG state tracking. To

achieve this functionality, you must group LAG 1 and LAG 2 into a single entity, called a failover group.

Configuring Shared LAG State Tracking

To configure shared LAG state tracking, you configure a failover group.

NOTE: If a LAG interface is part of a redundant pair, you cannot use it as a member of a failover group created for

shared LAG state tracking.

1. Enter port-channel failover group mode.

CONFIGURATION mode

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