(第3空)One of the most widely used routing protocols in IP networks is the Routing Information Protocol (RIP). RIP is the canonical example of a routing protocol built on the ( ) algorithm. Routing protocols in internetworks differ slightly from the idealized graph model. In an internetwork, the goal of the routers to forward packets to various ( ) .
outers running RIP send their advertisement about cost every ( ) seconds. A router also sends an update message whenever an update from another router causes it to change its routing table.
It is possible to use a range of different metrics or costs for the links in a routing protocol. RIP takes the simplest approach, with all link costs being equal ( ) . Thus it always tries to find the minimum hop route. Valid distances are 1 through ( ) .This also limits RIP to running on fairly small networks.