[c-nsp] OSPF stability issues with 12.2SXI on 6500/Sup720?

[Chuck Church]

Any control plane policing?  We had a similar issue at last job, turned out
a few of our OSPF sessions weren't placed in the above-best-effort class.
Our IA people running a network scanner occasionally without telling us
would cause many drops in the best effort class, causing OSPF session drops.
After adding those few OSPF sessions to the right class, problem went away.
This as with SXI3, and eventually SXI4.  Other than that, no issues.  That
was with VSS mode, and lots of DFCs, if that makes a difference.

Chuck

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Justin M. Streiner
Sent: Tuesday, January 03, 2012 6:42 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] OSPF stability issues with 12.2SXI on 6500/Sup720?

Has anyone seen any serious stability issues with OSPFv2 in 12.2(33)SXI? 
I've tried both SXI6 and SXI7 Advanced Enterprise, and in both cases, after
about two weeks of normal operation, OSPF sessions will start dropping on
the affected switch, due to an expired dead timer.  Devices at the other
ends of those adjacencies do not report them dropping for any odd reason,
but they do report the adjacencies re-establishing.  I've seen no underlying
interface-level errors.

The issue appears to be specific to OSPFv2.  I have not seen any stability
problems in OSPFv3 adjacencies on the same device.  It almost seems like
OSPFv2 in 12.2(33)SXI could be mangling hellos, or simply stop sending them.
Unfortunately I didn't have the time to investigate that in depth, during
the issue I dealt with today.

I backed off to 12.2(33)SXH5 Advanced IP Services and the problem went away.
This is the second time an upgrade to 12.2SXI was done and had to be backed
off.  I haven't found anything interesting in the release notes yet for
12.2SXH - 12.2SXJ that leads to an answer.  A cursory look through the bug
toolkit also didn't turn up any really good matches.

The overall configuration isn't terribly exotic.  The 6500 is dual-stacked
- IPv4 IGP is OSPFv2 and IPv6 IGP is OSPFv3.  There is one VRF being handled
by a separate OSPFv2 process in the box.  There are LDP and MSDP peers with
other core devices on the backbone.  No BFD, and currently no authentication
on the OSPFv2 neighbors.

I have a case open with TAC on this, but I wanted to see if these symptoms
line up with behavior that other people might have seen.

jms
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