[ih] Why did congestion happen at all? Re: why did CC happen at all?

Brian E Carpenter brian.e.carpenter at gmail.com
Sun Aug 31 18:30:04 PDT 2014


On 01/09/2014 09:40, Tony Li wrote:
> On Aug 31, 2014, at 1:20 PM, Miles Fidelman <mfidelman at meetinghouse.net> wrote:
> 
>> Last time I looked, bandwidth and delay were part of the metrics used in at least some routing tables (e.g.,  Cisco EGIRP) - which are at least indirect measures of congestion.  Or am I wrong here?
> 
> 
> Yes, but that’s maximum bandwidth and propagation delay, not queueing delay and folks don’t actually enable that part of the metric anyway.  Nothing dynamic here.
> 
> Oh, and the last poor soul who did enable all of the dynamic features of (E)IGRP ended up with a violently unstable network.

I vividly recall Ross Callon speaking about why QOS routing doesn't work
at an IETF meeting at least ten years ago, using the analogy of dancing
in your own shadow, with a practical demonstration that it can't be done.

  Brian






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