ospf logs

[Kashish_Patel]

We saw logs like this:

OSPF: warning: DD packet from <>: Options mismatch (13)

%OSPF-4-OSPF_ADJACENCY_TEARDOWN: NGB <> , interface <> adjacency dropped: DD packet mismatch, state was: FULL

invalid DD packet from <>: Master flag mismatch (14)

OSPF-4-OSPF_ADJACENCY_TEARDOWN: NGB <>, interface <> adjacency dropped: nbr did not list our router ID, state was: FULL

OSPF comes up and goes back. What may be the reason? It looks like that during DBD exchange, there was some issue regarding who is the master. But what exactly was the issue? Problem does not exist anymore but we would like to know the root cause.

[Anand G]

Hello Kashish,

The error messages says that, in the received DD (database descriptor) packet, Master flag is incorrectly set, means NBR did not listed our router ID.

In simple words, take the below simple connection.

R1---R2

Assume, R1 knows it as master, but when R2 is also sending DBD with the Master bit set, then the above condition appears, i.e., Mismatch condition.

Ideally, the negotiation happens based of ip address, probably highest ip address becomes master or other way.

A 'debug' might help during master/slave negotiation.

hope this helps!

Regards,

Anand G

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[paul driver]

Hello

Please review this link regards 2-way, exstart or exchange states

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094050.shtml

res

Paul

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Thanks.