[e2e] Question about propagation and queuing delays

Marc Herbert marc.herbert at free.fr
Mon Aug 22 11:43:37 PDT 2005

On Mon, 22 Aug 2005, David Hagel wrote:

> Thanks, this is interesting. I asked the same question on nanog and
> got similar responses: that queuing delay is negligible on todays
> backbone networks compared to other fixed delay components
> (propagation, store-and-forward, transmission etc). Response on nanog
> seems to indicate that queuing delay is almost irrelevant today.
> This may sound like a naive question. But if queuing delays are so
> insignificant in comparison to other fixed delay components then what
> does it say about the usefulness of all the extensive techniques for
> queue management and congestion control (including TCP congestion
> control, RED and so forth) in the context of today's backbone
> networks? Any thoughts? Are the congestion control researchers out of
> touch with reality?

The delay-based congestion control techniques you are talking about
are not based on a ratio but on a delta between instant and constant

This still does not mean the measure is easy; but IMHO not for the
reason you give.

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