EIGRP Notes – Unequal Cost Path Load Balancing

Per the standard rules, please correct anything that’s wrong.

One of EIGRP’s big features is the ability to use unequal cost paths for load balancing.  This is done with the variance command.

variance : A multiplier used to calculate which feasible successors can be used as active routes.  The router takes integer and multiplies it by the successor’s feasible distance, and any FS with a an FD less than this new number gets submitted to the routing table manager.

R1(config-router)#variance ?
 <1-128>  Metric variance multiplier

maximum-paths : The maximum number of routes to submit to the route table manager.

R1(config-router)#maximum-paths ?
  <1-32>  Number of paths

traffic-share balanced : The router sends traffic based on a weighted values of the metric so that the lower metrics get more traffic.

R1(config-router)#traffic-share balanced

traffic-share min : Only use the lowest metric route.  This seems kind of pointless to me.

R1(config-router)#traffic-share min

traffic-share min across-interfaces : Use the lowest metric route but use routes out different interfaces if they exist.

R1(config-router)#traffic-share min across-interfaces

One response to “EIGRP Notes – Unequal Cost Path Load Balancing”

  1. Lindsay Hill Avatar
    Lindsay Hill

    I think the idea behind “traffic-share min” is to have the route already installed in the routing table, to minimise convergence time, isn’t it?

    Not that it’s going to make much difference, since the unused route will already be a feasible successor, having had to pass the FC in order to be used with variance.

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