Re: [ns] reworded ECN problem in NS

[Sally Floyd <floyd@aciri.org>]

>But i wrote this based on the implementation of one member function of
>TCP agent class in NS which is called whenever an ECE Ack is received. 

Are you using ns-2.1b6?  There was a bug that was fixed on
May 15, that involved a retransmit timer being incorrectly reset.

>From CHANGES.html at "http://www.isi.edu/nsnam/ns/CHANGES.html":

[floyd] Mon May 15 22:58:15 PDT 2000
    Added bug-fixes to tcp.cc for the case with ECN when cwnd < 1. The
    first fix is not to reset the retransmit timer when a new ack
    arrives and cwnd < 1. The second fix is, when the retransmit timer
    expires and cwnd < 1, to reset cwnd to 1. The first bug was reported
    by Yin Zhang. I also added four new ECN validation tests to test
    these bugfixes, ./test-all-ecn ecn_secondpkt1Ecn_tahoe,
    ecn_smallwin1Ecn_tahoe, ecn_smallwin2Ecn_tahoe, and
    ecn_smallwin3Ecn_tahoe. 

- Sally
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http://www.aciri.org/floyd/
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