OSPF Adjacency Process?

mitchtin

Hi, I understand the process that is gone through for routers configured with OSPF to become neighbors, but I don't quite understand what determines whether they progress from that and form an adjacency? thus exchanging OSPF database information.

Is it only DR's and BDR's that form adjacencies?

DCD

Your question is vague. No you don't need a DR and BDR for adjacency. In a point-to-point network configuration doesn't use a DR and BDR for adjacency. Use this show command "show ip ospf interface faX/X. To change the network type use "ip ospf network point-to-point".

theodoxa

On a multiaccess network, routers will only proceed past 2-Way with the DR and BDR. They will not form full adjacencies with other routers. These neighbors will be listed a "DROTHER" and will only get as far as the 2-Way state. On network types that don't use a DR/BDR (point-to-point), the two routers should become fully adjacent.

james43026

Here is a really good article on the OSPF neighbor establishment process. Just too much info for lazy ole me to type out right now. Theodoxa has pointed out a key aspect of OSPF, and how OSPF routers exchange updates. It's very important.