EIGRP Equal and UnEqual cost load balancing

By default, EIGRP load balances across up to 4 equal cost paths. EIGRP can also load balance over unequal cost paths as well.

1. How do I turn off EIGRP load balancing?

A. maximum-paths 1

2. How do I load balance over 16 paths

A. maximum-paths 16

3. I set up load balancing and am trace-routing the destination from my console, but it is only using one path

A. Load balancing is performed only on traffic passing through the router, not router generated traffic

4. I want to set up unequal cost load balancing, what do I do?

A. First you must determine the variance you wish to use. Take your FD (Feasible Distance) of your best route. Now what number do you need to multiply it by to include the FD of all other routes you wish to load balance across?

For instance, if your successor, or best route, has a FD of 10, and you want to load balance across paths with costs of 15 and 20, choose a variant of 2. Then, all FDs 20 or under will be included in unequal cost load balancing. If you wanted to load balance across a 25, choose a variance of 3 to include all FDs under 30. (*Note* to avoid loops, the FD of routes must also be less than the advertised distance of your successor route. Read my last post for more on this)

traffic-share balanced

variance [#]

5. The load balancing command also has a minimum command, when would I use that?

A. The traffic-share min across-interfaces command is used for OSPF and other protocols to turn on equal-cost load balancing. If you have changed to unequal cost load balancing you could use this to return to equal cost in EIGRP. This command will leave all of your variance chosen paths in the routing table (see #4) but packets will only be routed out the paths that are the least cost (minimum) route(s).