Re: Anyone encountered Cisco ATM PVC large delay bug?

["Yu Ning" <yuning () cndata com>]

Hi,

----- Original Message ----- 
From: Alex Rubenstein <alex () nac net>
To: Yu Ning <yuning () cndata com>
Cc: nanog-post <nanog () merit edu>
Sent: Friday, April 21, 2000 8:01 AM
Subject: Re: Anyone encountered Cisco ATM PVC large delay bug?


> Are you accounting for ATM overhead? Remember, the sho in bits/sec do NOT
> count overhead (another words, they are looking at true bits/sec, not
> cells/sec).
>
> You should check cells/sec on the ATM port you are connected to.
Yes. I get the utilization statistic from ATM PVC statistic.


> > In more detail, our situation is: if we get a high bandwidth PVC,
> > say 51M(or 80M), and if the bandwidth utilization reaches 80%
> > percent, the ATM link will encounter a 1500~2000 ms delay - just
> > point to point ping across the link. We have found this situation 
> > is associated with "sar txpool" setting in Cisco GSR, and a manipulation
> > of the "sar txpool" together with bandwidth increasing has solved
> > the problem now.
> >
> > But I still wonder if any of you ever encounter this situation(bug),
> > and how did you overcome it? If you are still puzzled by this bug,
> > I'd like share our temp solution with you.
> >
> >
> > regards,
> >
> > Yu Ning
> >
> > -------------------------------------------
> > (Mr.) Yu Ning 
> > ChinaNet Backbone Operation
> > Networking Dep.,Datacom Bureau
> > China Telecom.,Beijing(100088),P.R.C
> > +86-10-66418121/66418122/66418123(fax)
> > -------------------------------------------