[c-nsp] Stale tcp connection on FWSM

[Andrew Yourtchenko]

On Tue, 29 Dec 2009, Matthew Melbourne wrote:

> Thanks for your reply. It looks like it could be oversubscription of the
> session path, though I am not completely familiar with the internal
> architecture of the FWSM.
>
> system/xxx# show np all stats | inc Close
> PKT_CNT: Close indication sent                     : 1929469548
> PKT_CNT: Close indication sent                     : 946451842
>  Close Indications      : 4197817416

Ok so looks like we even wrapped around, since the sum of the first two is 
smaller than the third.

>    Close Notify Errors    : 16
> How could I determine if this is genuine oversubscription?

That will depend quite a lot on the traffic mix and the configuration, as 
well as on the available means of telemetry - so unfortunately it's hard 
to give a one-size-fits-all approach that would fit into a single mail :-)

I'll send you some more questions unicast to understand better what we can do.

> Are there any
> recommendations for mitigating the issue with the current code base?

The "easy" way in this scenario is to not limit the total number of 
connections - that would at least prevent the blocking that you observe.

kind regards,
andrew