Point to point T1 neighbor priority 0

[jim.brown]

Why would a neighbor on a point to point T1 have a priority of 0 when there is no priority configured on the serial interface? For example:

Router2#sh ip ospf nei

Neighbor ID Pri State Dead Time Address Interface

10.192.254.7 0 FULL/ - 00:00:34 10.192.10.45 Serial0/0

Router2#sh run

interface Serial0/0

ip address 10.192.10.46 255.255.255.252

ip ospf message-digest-key 1 md5 7 00263B352B683B205E711C

no fair-queue

Router1#sh ip ospf nei

Neighbor ID Pri State Dead Time Address Interface

10.192.254.13 1 FULL/ - 00:00:36 10.192.10.46 Serial1/0/0:0

Router2#sh run

interface Serial1/0/0:0

ip address 10.192.10.45 255.255.255.252

ip ospf message-digest-key 1 md5 7 00263B352B683B205E711C

no fair-queue

Thanks

[mmolina10855]

Since there is no DR election on "point-to-point" OSPF networks (assuming everything is left at default), IOS considers the routers at both ends of the circuit to be ineligible for DR/BDR status/election and assigns them both local priorities of zero. I suppose it might have been more logical to place a "-" or a "n/a" in the priority column but it pretty much indicated the same thing at the end of the day :-)

[mmolina10855]

I suppose I should qualify my last comment by stating that the priority on point-to-point links does not appear to be consistent (at least not on the devices I have looked at). On some, one end is set to zero and the other is set to 1. On other devices, both sides are set to zero. I would have thought that both ends would be zero everytime but I guess I was wrong.

[Richard Burts]

I am guessing that there are IOS version differences between the routers that assign value 0 and routers that assign value non 0 for OSPF neighbor priority on point to point interfaces.

I believe that the first point made by Martin is the important one. Since there is never any election for DR/BDR on OSPF point to point interfaces whatever value the priority field may have is not relevant.

HTH

Rick

[jim.brown]

Thanks for the reply. I knew that there was no DR/BDR election on point to point links, I just did not understand why the priority was zero. Thanks again.