Link Aggregation Control Protocol | 547Figure 24-5. LAGs using ECMP without Shared LAG State TrackingTo avoid packet loss, traffic must be re-directed through the next lowest-cost link (R3 to R4). FTOS has theability to bring LAG 2 down in the event that LAG 1 fails, so that traffic can be re-directed, as described.This is what is meant by Shared LAG State Tracking. To achieve this functionality, you must group LAG 1and LAG 2 into a single entity, called a failover group.Configure Shared LAG State TrackingTo configure Shared LAG State Tracking, you configure a failover group:In Figure 24-6, LAGs 1 and 2 have been placed into to the same failover group.Figure 24-6. Configuring Shared LAG State TrackingView the failover group configuration using the show running-configuration po-failover-groupcommand, as shown in Figure 24-7.Figure 24-7. Viewing Shared LAG State Tracking in the Running-configurationStep Task Command Command Mode1 Enter port-channel failover group mode. port-channel failover-group CONFIGURATION2 Create a failover group and specify thetwo port-channels that will be membersof the group.group number port-channelnumber port-channel numberCONFIG-PO-FAILOVER-GRPPo 1Po 2fnC0049mpR1R2 R3R4Po 1 failurePo 2 over-subscribedR2#configR2(conf)#port-channel failover-groupR2(conf-po-failover-grp)#group 1 port-channel 1 port-channel 2R2#show running-config po-failover-group!port-channel failover-groupgroup 1 port-channel 1 port-channel 2
