An Uncalled-for DR Election in OSPF

Unanswered Question
Feb 20th, 2009

Four routers are connected via token-ring in Area 0. RID is DR, is BDR. DRothers are and

I powered down. Switched it right the hell off. Felt no guilt; would do it again.

I was logged on, console-like, to Router G ( with OSPF Adjacency debugging activated, and here's part of what I saw:

01:08:28: OSPF: address on TokenRing0 is dead

01:08:28: OSPF: address on TokenRing0 is dead, state DOWN

01:08:28: %OSPF-5-ADJCHG: Process 100, Nbr on TokenRing0 from FULL to

DOWN, Neighbor Down: Dead timer expired

01:08:28: OSPF: Neighbor change Event on interface TokenRing0

01:08:28: OSPF: DR/BDR election on TokenRing0

01:08:28: OSPF: Elect BDR

01:08:28: OSPF: Elect DR

01:08:28: DR: (Id) BDR: (Id)

The router that went down was neither DR nor BDR. Why was there a DR election reported? Does this always happen when there's a neighbor change event on a multiaccess interface? That doesn't jibe with my training, which says that an election won't take place unless the existing DR goes down.

I have this problem too.
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marikakis Sat, 02/21/2009 - 07:59

You are right and this is not normal behavior. DR election in OSPF is not even preemptive. The routers that go into the election process in your case are running buggy software. I have come across this issue before.

Mohamed Sobair Sun, 02/22/2009 - 01:02


According to the RFC, when topology changes (Router failure), a new election of a DR has to occur. This applicable in the Multi access Networks of course where there is DR & BDR election.




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