JNCIA-Junos Practice Test 2025 – Complete Exam Preparation

OSPF, or Open Shortest Path First, utilizes link-state routing to determine the best path to a destination. Link-state routing protocols operate by having each router maintain a complete topology of the entire network. Each router discovers its neighboring routers and collects information about them, ultimately flooding this information throughout the network. This enables OSPF routers to construct a detailed map of the network, known as the link-state database.

Once each router has the complete topology information, it employs the Dijkstra algorithm (or Shortest Path First algorithm) to compute the shortest path to each destination based on various metrics, such as cost. The use of link-state routing allows OSPF to converge quickly and adapt to changes within the network more efficiently than other types of routing protocols.

The other routing types relate to different mechanisms. For example, distance vector protocols determine the best path based on distance metrics from neighboring routers and can be slower to converge. Path vector protocols are used primarily in BGP (Border Gateway Protocol) for inter-domain routing, focusing on the path information carried in routing updates. Hybrid protocols combine features of both distance vector and link-state mechanisms but are not applicable in the context of OSPF. Consequently, link-state is the correct answer for OSPF