ECMP (Equal Cost Multi Path)

If the total IGP cost to a destination are same for two path, these paths are called Equal Cost Multi Path. Normally if there are two path that have same IGP cost, in Alcatel-Lucent Service Routers, lower interface wins and the traffic goes through it.

 

Traffic Flow Without ECMPThink about the above topology, without ECMP the traffic only goes through the A path. And when you use the below commands to see the tables, you will realize the below results:

show router ldp bindings (2 path, A and B)

show router fib 1 (1 path, A)