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jbaird
newbie
Topic Author
Posts: 48
Joined: Tue May 10, 2011 6:11 am

OSPF problem with Cisco

Wed Oct 26, 2011 4:28 pm

Hi,

I have a 450G running 5.2 that has an established OSPFv2 session with a Cisco 3560 that is having problems dropping.

On the Cisco side, I see:

Oct 26 05:24:54: %OSPF-5-ADJCHG: Process 1, Nbr 209.x.x.14 on Vlan84 from FULL to EXSTART, SeqNumberMismatch
Oct 26 05:24:54: %OSPF-5-ADJCHG: Process 1, Nbr 209.x.x.14 on Vlan84 from EXSTART to EXCHANGE, Negotiation Done
Oct 26 05:24:54: %OSPF-5-ADJCHG: Process 1, Nbr 209.x.x.14 on Vlan84 from EXCHANGE to LOADING, Exchange Done
Oct 26 05:24:54: %OSPF-5-ADJCHG: Process 1, Nbr 209.x.x.14 on Vlan84 from LOADING to FULL, Loading Done

On the 450G, I see:

OSPFv2 neighbor 209.x.x.x: state change from FULL to DOWN.

The OSPF session then comes right back up, but this is causing connected routes on the 450G to drop. I have numerous other 450G's in the field that have OSPF sessions with Cisco gear running same/similar code with no issues. There is no packet loss between routers that could be causing the OSPF drops that we are aware of.

Cisco says this about "SeqNumberMismatch":
A. The OSPF neighbor was changed state from FULL to EXSTART because of the receipt of a Database Description (DBD) packet from the neighbor with an unexpected sequence number. SeqNumberMismatch means that a DBD packet during OSPF neighborship negotiation has been received that either:

* has an unexpected DBD sequence number

* unexpectedly has the Init bit set

* has an Options field differing from the last Options field received in a Database Description packet.
Has anyone else seen this? If so, what can I do to try and remedy this problem? Are there any more details that I can provide?

Thanks
 
jbaird
newbie
Topic Author
Posts: 48
Joined: Tue May 10, 2011 6:11 am

Re: OSPF problem with Cisco

Thu Oct 27, 2011 4:33 pm

Anyone have a suggestion?
 
Reiney
just joined
Posts: 24
Joined: Sat Feb 05, 2011 7:22 am

Re: OSPF problem with Cisco

Fri Oct 28, 2011 9:46 pm

Hi,

I have routerboards talking OSPF w/ a Juniper. Have not seen your problem yet
but if you do have 450s that are working, I would check the software/firmware
versions on the busted one against the others. It has to be a config/software problem
on that particular 450 if you know that the network is soild.

The Cisco docs say something about an "Init bit"; maybe the 450 is attempting to
initiate a completely new session rather than just a database update. Just guessing on
that one ... :-)


~Reiney

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