The metric for RIP is hop count.
The RIP process operates from UDP port 520; all RIP messages are encapsulated in a UDP segment with both the Source and Destination Port fields set to that value. RIP defines two message types: Request messages and Response messages. A Request message is used to ask neighboring routers to send an update. A Response message carries the update. The metric used by RIP is hop count, with 1 signifying a directly connected network of the advertising router and 16 signifying an unreachable network.
On startup, RIP broadcasts a packet carrying a Request message out each RIP-enabled interface. The RIP process then enters a loop, listening for RIP Request or Response messages from other ...