OSPF States

The following list describes each possible state of a neighbor relationship:

• Down— This is the first OSPF neighbor state. It means that no information (hellos) has been received from this neighbor.

• Attempt— This state is only valid for manually configured neighbors in an NBMA environment. In Attempt state, the router sends unicast hello packets every poll interval to the neighbor from which hellos have not been received within the dead

interval.

• Init— This state indicates that the router has received a hello packet from its neighbor, but the receiving router's ID was not included in the hello packet.

• 2-Way— This state indicates that bi-directional communication has been established between two routers.

• Exstart— Once the DR and BDR are elected, the actual process of exchanging linkstate information can start between the routers and their DR and BDR.

• Exchange— In the exchange state, OSPF routers exchange database descriptor

(DBD) packets.

• Loading— In this state, the actual exchange of link-state information occurs.

• Full— In this state, routers are fully adjacent with each other. All the router and

network LSAs are exchanged and the router databases are fully synchronized.