If an interface that had not been available becomes available, a router MUST reenable any static routes that use that interface. If routes that would use that interface are learned by the router, then these routes MUST be evaluated along with all the other learned routes, and the router MUST make a decision as to which routes should be placed in the forwarding database. The implementor is referred to Chapter [7], Application Layer - Routing Protocols for further information on how this decision is made.
A router SHOULD expedite the sending of new routing information to all routers with which it normally exchanges routing information.