Detailed Neighbor Establishment
This section discusses some of the common issues that you can encounter in an OSPF network, including questions and issues related to neighbor and database initialization.
Typically, you see OSPF go from 2-way to full; however, when a full state is reached, this reflects that the LSDBs (that is, all the database exchanges) have been completely exchanged between the two routers in question. This process differs from the Hello protocol and is the subtle difference between the two.
The following sections cover Hello protocol state and database exchange state changes.
Hello Protocol State Changes
The following is a brief description of the possible OSPF neighbor state changes when the Hello protocol is being used: ...