[e2e] TCP and Implementation Related Questions

Michael Welzl michael.welzl at uibk.ac.at
Sun Jul 23 23:05:25 PDT 2006

> 3) If an implementation only follows RFC 2581, then even for a
> rate-limited application, the cwnd will keep increasing, beyond the rate
> at which application is sending data. There are some interesting effects
> of this phenomena for CBR traffic. To check that, RFC 2861 proposed to
> limit cwnd increase if the cwnd was not fully utilized.

I don't think so; as far as I know, this is why the term
"FlightSize" was introduced - the calculations are not just
based on the previous value of cwnd, but the actual number
of bytes in flight.

> 4) Does ns2 implement RFC 2861? I don't think so because if I rate limit
> the application (use CBR over TCP), cwnd keeps increasing beyond the
> application rate.

Because we have the "Flightsize" term, with or without RFC 2861,
that shouldn't happen.


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