OSPF Error Messages

[admin_2]

Hi all,

can someone help to explain the error messages seen below and possible steps to fix the problem.

May 8 08:20:16: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from FULL to EXSTART, SeqNumberMismatch

May 8 08:20:16: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from EXSTART to EXCHANGE, Negotiation Done

May 8 08:20:16: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from EXCHANGE to LOADING, Exchange Done

May 8 08:20:16: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from LOADING to FULL, Loading Done

May 8 11:37:41: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from FULL to EXSTART, SeqNumberMismatch

May 8 11:37:41: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from EXSTART to EXCHANGE, Negotiation Done

May 8 11:37:41: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from EXCHANGE to LOADING, Exchange Done

May 8 11:37:41: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.130 on Vlan5 from LOADING to FULL, Loading Done

Thanks in advance

Sanjay

[rais]

Your link/network between the two routers seems to be droppig packets.

Thanks.

[AJAZ NAWAZ]

Hello Sanjay,

Take a look at this url:

<http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f0d.shtml>

In addition, the OSPF RFC 2328 , section 10.3, states that the exstart/exchange process is initiated for any of these events (any of which could be caused by internal software problems):

SequenceNumberMismatch

Unexpected DD Sequence number

"I" bit is set unexpectedly

Option field different from the last option field received in the DBD packet

I would suggest clearing your ospf processes and restart the neighborship from scratch. But, before you do that just make sure the routers are still show the problem by examining the output from show ip ospf neighbor.

hth

Ajaz Nawaz

[turbo_engine26]

This might help too

http://www.ietf.org/mail-archive/web/ospf/current/msg03050.html

[lgijssel]

From: http://www.cisco.com/en/US/partner/tech/tk365/technologies_q_and_a_item09186a0080094704.shtml#q45

Q. In the %OSPF-5-ADJCHG: Process ID, Nbr [ip-address] on Port-channel31 from FULL to EXSTART, SeqNumberMismatch error message, what does SeqNumberMismatch signify?

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.

(Unidirectional) packet loss is a possible cause.

regards,

Leo