Shared Lag State Tracking; Configuring Shared Lag State Tracking - Dell Force10 Z9000 Configuration Manual

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). Dell Networking OS 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
port-channel failover-group
2. Create a failover group and specify the two port-channels that will be members of the group.
CONFIG-PO-FAILOVER-GRP mode
group number port-channel number port-channel number
Example of LAGs in the Same Failover Group
In the following example, LAGs 1 and 2 have been placed into to the same failover group.
Dell#config
Dell(conf)#port-channel failover-group
Dell(conf-po-failover-grp)#group 1 port-channel 1 port-channel 2
To view the failover group configuration, use the show running-configuration po-failover-group command.
Dell#show running-config po-failover-group
!
port-channel failover-group
group 1 port-channel 1 port-channel 2
Link Aggregation Control Protocol (LACP)
379