Which OSPF neighbor state comes after "Init"?

In the process of establishing neighbor relationships in OSPF (Open Shortest Path First), the "Init" state signifies that an OSPF router has received a Hello packet from a neighbor but has not yet seen its own Router ID in the neighbor's Hello packet. The next state that follows "Init" is called the "2-way" state.

In the "2-way" state, the router has received Hello packets from its neighbor that include its own Router ID, which indicates mutual acknowledgment of the neighbor relationship. This state is crucial for ensuring that both routers are aware of each other and are considered neighbors. The transition to this state typically happens in multi-access networks (like Ethernet) where routers need to determine how many OSPF routers are on the segment. In a point-to-point connection, the next state would often transition directly to "Full."

The "2-way" state is fundamental for establishing correct communication and ensuring that OSPF can proceed to the subsequent stages, such as the “ExStart” and eventually the “Full” state, where the routers exchange their link-state information and install routing tables based on this information.

This overview emphasizes the importance of the "2-way" state as a key step in the OSP