Avaya 8600 Configuration Manual page 44

Link aggregation fundamentals
Figure 10: Problem description (1 of 2)
In the following figure, if the L2 link on S1 (S1/L2) fails, the link-down failure is not propagated
over the SP network to S2 and S2 continues to send traffic over the failed S2/ L2 link.
Figure 11: Problem description (2 of 2)
Use VLACP to detect far-end failures, which allows MLT to failover when end-to-end
connectivity is not guaranteed for links in an aggregation group. VLACP prevents the failure
scenario.
When used in conjunction with SMLT, VLACP allows you to switch traffic around entire network
devices before Layer 3 protocols detect a network failure, thus minimizing network outages.
44 Configuration — Link Aggregation, MLT, and SMLT
Comments? infodev@avaya.com
January 2012