[Iccrg] Re:

[Sally Floyd]

Saverio -

> what do you mean by "different level of congestion"?

Include "uncongested" scenarios, e.g., with low levels
of link utilization.  And include highly "congested" scenarios,
with high levels of link utilization and a range of packet
dropping and/or marking rates.

With the "different levels of congestion" produced by
scenarios with different levels of traffic.  E.g., the number
of web sessions started each second, the number of
long-lived flows, etc.

I don't have a proposal for a single metric that captures
the "level of congestion" in congested and uncongested
scenarios, however.  (It is not clear to me that we need one.)

- Sally



> On 11/6/07, Sally Floyd <sallyfloyd at mac.com> wrote:
> >> - The rise time of a single flow to an empty systems is not very
>> > interesting, because it many measures the impact of slow start.
>>
>> Actually, the flow completion time in an uncongested system can be
>> a quite interesting thing to measure, particularly if one is
>> evaluating one of the many proposals for start-ups faster than
>> slow-start.  (One of these proposals is Quick-Start, RFC 4782; some
>> of the others are discussed in Appendix A of RFC 4782.)
>>
>> I would recommend having scenarios include the case of a
>> generally-uncongested link, as well as including cases with various
>> levels of congestion, with metrics including per-flow transfer
>> times, fairness, and aggregate packet drop rates.  This should
>> illustrate some of the good and potentially-bad aspects of protocols
>> with fast start-ups.
>>
>> - Sally
>> http://www.icir.org/floyd/
>>
>> RFC 4782:  http://www.ietf.org/rfc/rfc4782.txt
>>
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>
>
>
- Sally
http://www.icir.org/floyd/