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Re: my 2p worth

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  • Vern Paxson
    ... Also, it would be very interesting (but hard to determine!) how much traffic each implementation contributes. This would let you gauge to what degree a
    Message 1 of 107 , Dec 5, 1996
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      > 1.It would be interesting to know how many independent
      > TCP implementations exist, and the rough proportions in
      > which they are represented.

      Also, it would be very interesting (but hard to determine!) how much
      traffic each implementation contributes. This would let you gauge to
      what degree a widespread PC implementation actually influences Internet
      traffic.

      One idea floating around is having as one of the group's products a Web
      page that would have this sort of info. Something along the lines of

      http://www.psc.edu/networking/perf_tune.html

      which Jamshid Mahdavi et al put together. There are IETF issues regarding
      a WG providing such a page which Allison & Allyn are looking into. We
      should have something more concrete to say about this at the BOF.

      > 2. It used to be the case that there were bugs in common implementations
      > that you had to workaround ...
      > it would be enormously useful to have these listed.

      Definitely! This is one of the central goals of the WG as I see it.

      > 3. Most of the bugs mentioned are protocol issues or end-to-end
      > performance issues on a single connection. Is it within scope to
      > mention scalability issues, e.g. supporting large numbers of
      > connections in TIME-WAIT?

      This also strikes me as within scope, though with the line drawn at
      the point where things cross into the research frontier. So, for example,
      the issues raised in Joe Touch's draft RFC are good things to discuss;
      but for some of them their resolution (e.g., how to share cwnd across
      multiple connections) is research and needs to be dealt with in another
      forum. It seems an important benefit of the WG is to highlight where
      the research frontier is, too, so implementors can gauge where different
      features lie.

      > 4. Are there bugs that crop up persistently in independent TCP
      > implementations? e.g. mishandling of queued data for transmission
      > when a close is issued? These would point to the most difficult
      > issues.

      Likewise, this strikes me as a mainstream goal for the proposed WG.

      > 5. Should we separate buggy implementations of algorithms and
      > inappropriate (or debatable) algorithms?

      Definitely, if by algorithm you mean what's specified in an RFC. We need
      to consider whether some of the RFC's need clarification or expansion, but
      this is a considerably more significant step than cataloging implementation
      issues.

      Vern
    • Steve Alexander
      ... I think the issue probably has more to do with interpreting what the urgent pointer means. If I remember correctly, 793 was ambiguous (it said two
      Message 107 of 107 , Feb 19, 1997
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        der Mouse <mouse@...> writes:
        >I don't think there _is_ any "correctly". TCP does not have OOB. What
        >it has is an urgent pointer. Some grad student who must have been
        >either on drugs or on a minimal understanding of TCP thought it would
        >be useful to take the byte the urgent pointer points to and treat it as
        >a byte in an out-of-band channel.

        I think the issue probably has more to do with interpreting what the urgent
        pointer means. If I remember correctly, 793 was ambiguous (it said two
        different things in two different places) and BSD picked the "wrong" one
        (having just re-read it, I probably would have too). If you follow 1122, then
        you disagree with BSD by one byte, which is a real pain. I don't know why the
        authors of 1122 didn't just admit defeat and codify the BSD practice ;->.

        -- Steve
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