What is Open Shortest Path First (OSPF)?

• A. Static routing protocol
• B. Dynamic routing protocol used in IP networks that is a Link-State routing protocol
• C. Wireless standard
• D. Congestion control algorithm

Answer: (B)

OSPF is a dynamic routing protocol used in IP networks that uses a link-state approach. Routers share link-state advertisements that describe the state and cost of their links, which lets every router build a complete map of the network topology in a common database. Each router then runs the shortest-path-first algorithm (the Dijkstra algorithm) on that topology to compute the best path to every destination. The path cost typically depends on link bandwidth, so faster links have lower cost and influence route selection.

OSPF scales well because it supports hierarchical design with areas and a backbone (area 0), which helps manage large networks. It also uses Hello packets to discover neighbors and form adjacencies, updating routes quickly when changes occur through LSAs rather than sending full routing tables periodically.

This makes OSPF dynamic and suitable for IP networks, in contrast to static routing, and it is not a wireless standard or a congestion control mechanism.