Calculate the RIP hop-count metric for a route and check it against the maximum hop limit.
RIP (Routing Information Protocol) is a distance-vector protocol that uses a simple hop count as its only metric — every router along a path adds 1 to the metric regardless of the link's actual bandwidth or delay, so a path through three routers has a metric of 3. RIP defines 15 hops as the maximum usable distance and reserves the value 16 to mean 'infinity,' i.e. unreachable; this deliberately small diameter limits RIP to small networks, since any destination more than 15 routers away cannot be represented.
RIP metric
metric = hop_count (0-15 reachable, 16 = unreachable)
RIP's metric field was designed to be small and simple, using a value of 16 to represent infinity/unreachable in a distance-vector protocol that needed a finite way to signal a destination is unreachable. This design choice deliberately limits RIP's usable network diameter to 15 hops, making it suitable only for small networks — larger networks need OSPF, EIGRP, or BGP.
No — RIP (versions 1 and 2) only counts hops, treating a slow 10 Mbps link and a fast 100 Gbps link identically as long as both add 1 to the path metric. This is a key limitation compared to link-state protocols like OSPF, which factor in bandwidth via interface cost.
A metric of 16 signals the destination is unreachable via that path (RIP's version of 'infinity'), which routers use to detect and remove failed or looped routes — RIP relies on this along with techniques like split horizon and route poisoning to converge after a topology change, though convergence is notably slower than link-state protocols.