In which OSPF state do routers just begin establishing adjacency?

In the OSPF (Open Shortest Path First) protocol, the Init state is the first state that a router enters when attempting to establish an adjacency with another OSPF router. During this state, a router sends out a Hello packet to its neighbor, and it is waiting to receive a Hello packet from that neighbor in return.

The Init state indicates that the router has received Hello packets from the neighbor but has not yet formed a full OSPF adjacency. This is an important stage in the OSPF process, as the routers must recognize each other as neighbors before proceeding to the next steps of the adjacency process. Once the routers acknowledge each other and the necessary parameters match, they can move on to the Exstart state, where they will begin to negotiate the master/slave relationship for the exchange of routing information.

Understanding the role of the Init state is crucial for grasping how OSPF builds its topology and maintains a synchronized view of the network among all routers involved.