Unequal Cost Load Balancing

It is possible to have unequal cost load balancing in CEF. In that case, the 16 hash buckets are not evenly distributed among all possible paths. Example 6-9 shows a router running Enhanced Interior Gateway Routing Protocol (EIGRP) as the routing protocol and variance being configured for EIGRP. Variance allows EIGRP to perform unequal cost load balancing because it enables routes to be installed in the routing table that are not the best. (These routes do not have the lowest metric.) In short, the variance number allows all routes that have a metric that is smaller than that of the best route multiplied by the variance to be installed in the routing table. One additional check is needed: The reported distance (metric ...

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