[c-nsp] arp timeout issues

[Rodney Dunn]

I don't know about those switches but can you see
if there is a 'sh ip cef event' and see if the adj
is being updated when the arp refresh happens?

I wonder if the hw adj is being updated and while we lock
the adjacency to update it we don't switch packets to it.

Have you put a sniffer on there to make sure the packets are
not going out?


On Sat, Feb 24, 2007 at 08:07:30PM -0000, Ed Butler wrote:
> Fairly standard set up; stack of 3750s running OSPF to 6500s. On the
> 3750s there are a number of SVIs, with "arp timeout 300" set on them.
> The same VLANs have a MAC againg time of 5 minutes too.
> 
> The behaviour we are seeing is that every six minutes (not 5) traffic to
> a host on the SVI will die for 500ms or so, and this coincides with the
> ARP entry being refreshed. CPU usage on the 3750 stack averages 15-20%.
> 
> We have a number of similar set up that don't replicate this problem.
> Has anyone seen similar and can recommend a course of action? Hopefully
> something more sophisiticated than simply increasing the ARP timeout!
> 
> Regards,
> 
> Ed Butler
> RapidSwitch Ltd
> DDI: 020 7106 0731
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