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Re: window update algorithm

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  • Francesco Potorti`
    When updating the right edge of the send window, i.e., when SND.UNA
    Message 1 of 38 , Dec 31, 1969
      When updating the right edge of the send window, i.e., when

      SND.UNA <= SEG.ACK =< SND.NXT,

      Jerry proposes to substitute the standard test (rfc793 page 72,
      corrected by rfc1122-4.2.2.20.g) with the following one:

      SND.WND < SEG.WND or SND.WL < SEG.ACK,

      with the assumption that shrinking the window is legal (as is now),
      and that SND.WL contains the SEG.ACK of the last segment used to
      update the send window.

      Anyway, this test allows the sender to shrink the window only while
      advancing SEG.ACK, thus preventing the sender from shrinking its
      receive window when the connection is idle, which is allowed by the
      test in rfc793.

      If instead shrinking the window is allowed in any situation when an
      ACK is considered for window update, the current behaviour is
      preserved and the test is further simplified -- actually it
      disappears.

      In practice: the standard test on the SEG.SEQ makes no sense, as Jerry
      argued previously, and the standard test on SEG.ACK is implied by the
      first test on the window update, as Jerry noted, so no further test is
      needed!

      Too good to be true? :-)

      --
      Francesco Potorti` (researcher) Voice: +39-50-593203
      Computer Network Division Operator: +39-50-593211
      CNUCE-CNR, Via Santa Maria 36 Fax: +39-50-904052
      56126 Pisa - Italy Email: F.Potorti@...
    • Larry Backman
      ... Mbone coverage for those of us who don t want to see how lovely the Memphis hotel situation is :-)?
      Message 38 of 38 , Mar 13, 1997
        ||We've been given the following slot:
        ||
        || Tuesday, April 8 at 1530-1730 (opposite grip, disman, drums,
        || spki, idmr,issll)
        ||

        Mbone coverage for those of us who don't want to see how lovely the
        Memphis hotel situation is :-)?
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