A general term indicating a protocol run between routers and/or route servers in order to exchange information used to allow computation of routes. The result of the routing computation will be one or more forwarding descriptions.
Used by routers to create & maintain routing tables, which provide information on the current state of a network and determine the best path to route packets. Example routing protocols include RIP and EIGRP. A routing protocol is associated to a network protocol (IP, IPX, etc). In general, there are two types of routing protocols; Distance-Vector and Link State. Routing protocols use "metric" data to determine the best path to a specified network. Example metrics are hop count, cost, bandwidth, delay, and MTU (Max Transfer Unit).
A series of periodic or on-demand messages containing routing information that is exchanged between routers to exchange routing information and provide fault tolerance. Except for their initial configuration, dynamic routers require little ongoing maintenance, and therefore can scale to larger internetworks.