Configuring ECMP Round-Robin Load Sharing

ECMP uses the round-robin mode when you have configured all interfaces in the set to round-robin. Otherwise, ECMP defaults to hashed mode because round-robin mode can cause reordering of packets. You must explicitly ensure that the possible reordering is acceptable on all the member interfaces by setting them to round-robin mode.

If one of the ECMP next hops is an indirect next hop, ECMP uses hashed mode load balancing.

To specify round-robin as the mode for ECMP load sharing:

• Issue the ip multipath round-robin command in Subinterface Configuration mode.
  host1:router_0(config-subif)#ip multipath round-robin

  Use the no version to set the ECMP mode to the default, hashed.