[28223] in North American Network Operators' Group
Re: Anyone encountered Cisco ATM PVC large delay bug?
daemon@ATHENA.MIT.EDU (Alex Rubenstein)
Thu Apr 20 20:01:08 2000
Date: Thu, 20 Apr 2000 20:01:52 -0400 (Eastern Daylight Time)
From: Alex Rubenstein <alex@nac.net>
To: Yu Ning <yuning@cndata.com>
Cc: nanog-post <nanog@merit.edu>
In-Reply-To: <002701bfab20$33b0ef40$9c0361ca@chinanet.cn.net>
Message-ID: <Pine.WNT.4.05.10004202001030.1592-100000@shakalaka>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Errors-To: owner-nanog-outgoing@merit.edu
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.
> 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)
> -------------------------------------------
>
