[c-nsp] OSPFv3 down every 34 minutes

[Eric Van Tol]

Hi Brad,
Thanks for the response.  I saw those drops, but they don't come close to the amount of times this is occurring.  This happens literally, every 34 minutes (okay, 33 minutes and some seconds :-) ):

Apr 13 06:13:03 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.10 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 06:13:03 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.9 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 06:13:07 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.11 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 06:46:52 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.10 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 06:46:53 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.9 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 06:46:57 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.11 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 07:20:35 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.10 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 07:20:36 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.11 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 07:20:40 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.9 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 07:53:48 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.10 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 07:53:49 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.11 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 07:53:52 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.9 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 08:27:36 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.11 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 08:27:37 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.10 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 08:27:42 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.9 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 09:01:31 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.10 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 09:01:31 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.11 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits
Apr 13 09:01:35 EDT: %OSPFv3-5-ADJCHG: Process 600, Nbr x.x.x.9 on Vlan2 from FULL to DOWN, Neighbor Down: Too many retransmits

The interfaces all show the same info:

  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0

On the Vlan2 interface, I show one more drop since I sent the original message on Friday:

  Input queue: 0/75/17/17 (size/max/drops/flushes); Total output drops: 0

I'm baffled at this point.  I'll likely be moving to IS-IS soon, but this is one of those problems that really makes you wonder.

________________________________________
From: Brad Henshaw [brad.henshaw at qcn.com.au]
Sent: Sunday, April 13, 2008 9:13 AM
To: Eric Van Tol; cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] OSPFv3 down every 34 minutes

Eric Van Tol wrote:

> In any case, the question now is, what would cause so many
> neighbors to retransmit and why on only one router?

Packet loss or congestion on the physical links/interfaces
connecting to this router?

Not sure why it'd be every 34 minutes though. If it were every
/30/ minutes, the OSPF refresh would be a real suspect.
I notice input drops are shown for int vl2. Check these for
the relevant physical interface(s) also.

~Brad