•Stub Area Flag − any two routers also have to have the same stub area flag in their Hello packets in order to become neighbors.
Adjacencies
Adjacent routers go beyond the simple Hello exchange and participate in the
Designated Router Election
The election of the DR and BDR is accomplished using the Hello protocol. The router with the highest OSPF priority on a given
Building Adjacency
Two routers undergo a
•Down − No information has been received from any router on the segment.
•Attempt − On
•Init − The interface has detected a Hello packet coming from a neighbor but bi- directional communication has not yet been established.
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•Exstart − (Exchange Start) Routers establish the initial sequence number that is going to be used in the information exchange packets. The sequence number insures that routers always get the most recent information. One router will become the primary and the other will become secondary. The primary router will poll the secondary for information.
•Exchange − Routers will describe their entire
•Loading − The routers are finalizing the information exchange. Routers have
•Full − The adjacency is now complete. The neighboring routers are fully adjacent. Adjacent routers will have the same
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