Monday, 14 October 2013

ROUTE: EIGRP Load Balancing

ROUTE; EIGRP Load Balancing




  • Configure basic settings
  • Identify successors, feasible successors, and feasible distances
  • Use debug commands for EIGRP topology table
  • Configure and verify equal-cost load balancing
  • Configure and verify unequal-cost load balancing


Configure basic settings

I've configured the bandwidth 64 command on all the routers.


By viewing the information below, you can see that routes are being placed into the routing table.

We can verify what we see above with the following commands;


Identify successors, FS, and FD's

The show ip route eigrp command shows the current successor routes. You can view the entire topology including feasible successors and their feasible distances. This can be done with the following command;

Configure and verify equal-cost load balancing

You can see from the topology and routing table that the network is available both through R2 and R3. If you issue a trace route to, you will notice that both of these routes are listed as they are both equal cost paths.

Configure and verify unequal-cost load balancing

To demonstrate unequal-cost load balancing, I can upgrade the speed of R1 to R2 and R1 to R3 links.

R3 now prefers to reach R2 loopbacks via R1 (

To enable unequal-cost load balancing we can issue the variance 2 command on R3;

You can verify the changes by viewing the routing table;

The unequal-cost routes will also show up in the topology table;

You can use the following command to view how the traffic is shared between the two links (traffic share count);

I set the repeat to 49 so that the last packets will take a different route.

To demonstrate this I disabled CEF with the no ip cef global command and the no ip route-cache under the serial interfaces. I also created the following ACL to filter out the debugging;