What is the primary routing metric used by Routing Information Protocol (RIP)?

The primary routing metric used by Routing Information Protocol (RIP) is hop count. RIP is a distance-vector routing protocol that measures the distance to a destination in terms of the number of hops required to reach that destination. Each hop represents a router that must be traversed to get from the source to the destination. The protocol considers a maximum of 15 hops, with 16 hops designated as unreachable, which limits the size of the network that RIP can effectively manage.

This metric is simple to implement and provides a straightforward way to determine the best path to a destination. While RIP also falls into the category of distance vector protocols, the unique metric that primarily defines its routing decisions is indeed hop count, which helps in determining the most efficient route based on the number of routers crossed.

Other options like cost, load balancing, and the general classification as a distance vector do not accurately capture the primary metric used by RIP to route packets, focusing instead on different networking principles or other routing protocols.