Which routing protocol is a distance-vector protocol that uses hop count and has a maximum of 15 hops?

Which routing protocol is a distance-vector protocol that uses hop count and has a maximum of 15 hops?

• A. BGP
• B. OSPF
• C. EIGRP
• D. RIP

Answer: (D)

Distance-vector routing that uses a simple hop-count metric with a hard limit of 15 hops is RIP. In RIP, each route’s value is the number of hops to the destination, and any route requiring more than 15 hops is considered unreachable (a distance of 16 means infinity). This tiny hop-limit is what makes RIP uniquely identifiable among common routing protocols. RIP exchanges its routing information by sending its entire distance-vector to neighboring routers at regular intervals, which is a hallmark of distance-vector behavior. The original implementation uses UDP for updates and relies on the Bellman-Ford algorithm to compute the best path based on hop count. Because updates happen periodically and the metric is just hops, convergence can be slow and the protocol is more prone to routing loops in larger or unstable networks. The other protocols don’t fit this description: BGP uses a path-vector approach with AS-paths and policy-based routing, not a hop-count metric. OSPF is a link-state protocol that builds a full topology map and uses shortest-path calculations, not hop counts. EIGRP is a hybrid protocol that uses a composite metric (bandwidth, delay, reliability, load) and supports many more hops, not a fixed 15-hop limit. So the protocol described is RIP.

Distance-vector routing that uses a simple hop-count metric with a hard limit of 15 hops is RIP. In RIP, each route’s value is the number of hops to the destination, and any route requiring more than 15 hops is considered unreachable (a distance of 16 means infinity). This tiny hop-limit is what makes RIP uniquely identifiable among common routing protocols.

RIP exchanges its routing information by sending its entire distance-vector to neighboring routers at regular intervals, which is a hallmark of distance-vector behavior. The original implementation uses UDP for updates and relies on the Bellman-Ford algorithm to compute the best path based on hop count. Because updates happen periodically and the metric is just hops, convergence can be slow and the protocol is more prone to routing loops in larger or unstable networks.

The other protocols don’t fit this description: BGP uses a path-vector approach with AS-paths and policy-based routing, not a hop-count metric. OSPF is a link-state protocol that builds a full topology map and uses shortest-path calculations, not hop counts. EIGRP is a hybrid protocol that uses a composite metric (bandwidth, delay, reliability, load) and supports many more hops, not a fixed 15-hop limit.

So the protocol described is RIP.