Which of the following protocols is a distance-vector routing protocol?

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

Answer: (B)

Distance-vector routing relies on routers periodically sending their entire routing table to their directly connected neighbors, with each router choosing the best path based on a simple metric like hop count. This approach is simple and easy to implement, but it can converge slowly and is more prone to routing loops if not carefully managed.

Among these options, the one that uses this traditional distance-vector method is RIP. It counts hops as its metric and uses periodic updates to neighbors. OSPF, on the other hand, builds a complete map of the network and runs a shortest-path algorithm (link-state). BGP operates as a path-vector protocol, tracking AS hops and attributes to determine routes. EIGRP is typically described as enhanced distance-vector (a hybrid), incorporating some advanced features beyond a basic distance-vector algorithm, but it’s not the classic distance-vector example like RIP.