OSPF Adjacency States

B

In Open Shortest Path First (OSPF) protocol, routers establish neighbor relationships by exchanging Hello packets with each other. The process of establishing neighbor relationships is called adjacency formation. There are several adjacency states in OSPF protocol, and each state indicates a specific point in the process of forming the adjacency.

The four possible OSPF adjacency states are:

1. Down: In this state, no communication has been established between two routers.
2. Init: In this state, a Hello packet has been received from a neighboring router, but bidirectional communication has not been established.
3. 2-way: In this state, bidirectional communication has been established, and the routers have agreed to become neighbors.
4. ExStart: In this state, the routers are preparing to exchange database information.

Therefore, the correct answer to the question is B. Init, which is the adjacency state reached when a Hello packet has been sent, but bidirectional communication has not been established. Once the bidirectional communication is established, the adjacency moves to the 2-way state, where the routers can exchange routing information.