As an example, IGRP is able to handle multiple routes with equal or unequal metrics. The traffic can then be split across the multiple routes depending upon the routes metric.
How is this accomplished? Equal-cost load balancing is controlled by the maximum-paths command. It's located in the router IGRP configuration. To separate traffic using unequal metrics IGRP uses the bandwidth statement. Below is an example of unequal routing using IGRP.
interface Ethernet0 ip address 192.168.x.x 255.255.0.0 interface Serial0 ip address x.x.x.0 255.255.255.192 bandwidth 768 interface Serial1 ip address y.y.y.0 255.255.255.192 bandwidth 512
This was first published in February 2003