OSPF - DR question

[joeadiutori]

Hi All,

My book tells me that ...  "a designated router election has been held, with Router A winning the election. With a DR, the topology

exchange process happens between the DR and every other router, but not between every

pair of routers. As a result, all routing updates flow to and from Router A."

My question is ..... are Routers B and C considered "neighbors" anymore, or is Router A the only one with "neighbors"?  Do B and C still exchange hello messages ???  They used to be such good friends until the election, and now everything is so political.

[Jon Marshall]

Joe

They used to be such good friends until the election, and now everything is so political.

With OSPF there is the concept of a neighbor and an adjacency. A neighborship is formed when valid hello packets have been exchanged. An adjacency is the next step where the OSPF database is then synchronised between the devices.

So the DR and the BDR will have an adjacency with all the other routers.

The non DR and BDR will form adjacencies with the DR and BDR but will only form neighborships with each other.

Edit - see this link for more details as to the actual states of the routers in a DR/BDR environment -

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094059.shtml

Jon