[52535] in North American Network Operators' Group
Re: UUNET Routing issues
daemon@ATHENA.MIT.EDU (Iljitsch van Beijnum)
Thu Oct 3 18:02:04 2002
Date: Fri, 4 Oct 2002 00:00:30 +0200 (CEST)
From: Iljitsch van Beijnum <iljitsch@muada.com>
To: Marshall Eubanks <tme@multicasttech.com>
Cc: <nanog@merit.edu>
In-Reply-To: <3D9CB791.4030402@multicasttech.com>
Errors-To: owner-nanog-outgoing@merit.edu
On Thu, 3 Oct 2002, Marshall Eubanks wrote:
> Where are they diverting it to, the Moon (1.5 light seconds away) ?
> Really - I have seen some multisecond latencies on network links we were
> testing, and I always wondered how these could come to be.
Good question. Cisco routers use a default queue size of 40 packets. That
will give you a ~2 second delay on a 128 kbps line. I seem to remember
that during my tour of duty at UUNET we had slightly faster lines... But
that was back in the good old days when life was good.
At 155 Mbps you need 32 MB worth of buffer space to arrive at a delay like
this. I wouldn't put it past ATM vendors to think of this kind of
over-enthusiastic buffering as a feature rather than a bug.
Does anyone have any thoughts on optimum buffer sizes?
