Redistributed routes are treated differently depending on which routing protocol they are being redistributed into. On IOS, each routing protocol has its own seed metric which is assigned by default to redistributed routes when no metric is configured manually. Below is a table listing the default behavior when no metric is defined with the metric argument on the redistribute command.

As illustrated in the table, routes being distributed from another routing protocol into RIP or EIGRP must have a configured metric to be eligible for placement in the RIP database or EIGRP topology. Also interesting to note is that BGP will automatically assigned the IGP-learned metric of a redistributed route to the route’s MED in the BGP table.