[c-nsp] 7600 cef confusion

[Charles Spurgeon]

On Mon, Jan 29, 2007 at 06:59:06PM +0200, Saku Ytti wrote:
> On (2007-01-29 17:06 +0200), Dmitry Kiselev wrote:
> 
> > Seems something wrong with cef adjacencies on my 7600/3bxl switch:
> 
> Stab in the dark, 
> 
> 1) disable proxy-arp
> 2) clear ip route
> 3) clear arp-cache
> 4) remove the ip address, add it again

We've used steps 2-4 in the past, but have noticed that steps 2 and 3
no longer seem to work. 

We've also had some luck with setting a /32 static route to null0 for
an affected address and then removing the static route, which forces a
cef adjacency rebuild. This can help avoid things like a shut/no shut
on the interface or removing the whole interface addr to force adj
rebuilds.

After complaining to Cisco about cef rot that persists even after
clearing arp and ip routes, we were told to enable cef consistency
checking in SXF code. 

Apparently these commands are disable by default on the 6500/7600
platforms:
ip cef table consistency-check error-message 
ip cef table consistency-check auto-repair

Once that is done you can see results in a show command:
sh ip cef inconsistency

As I recall, the cef consistency checker didn't exist in SXD code we
had been running. We've only recently migrated to SXF and haven't
started using the consistency checker yet so I don't have any real
world experience to report.

Thanks,

-Charles

Charles E. Spurgeon / UTnet
UT Austin ITS / Networking
c.spurgeon at its.utexas.edu / 512.475.9265