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

[John Day]

I like the analogy.  That makes all sorts of sense.  They are really 
separate problems that operate on different time scales.  From 
control theory one knows that mixing time scales is seldom a good 
idea.  ;-)

At 1:30 PM +1200 9/1/14, Brian E Carpenter wrote:
>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