[tcpm] TCP retransmission timeouts (RFC 2988)

(Resent to tcpm list, instead of iccrg)

After some discussion on the Linux networking list I thought I'd ask
the question here.

In RFC 2988 Section 2.4 says:
  (2.4) Whenever RTO is computed, if it is less than 1 second then the
        RTO SHOULD be rounded up to 1 second.

        Traditionally, TCP implementations use coarse grain clocks to
        measure the RTT and trigger the RTO, which imposes a large
        minimum value on the RTO.  Research suggests that a large
        minimum RTO is needed to keep TCP conservative and avoid
        spurious retransmissions [AP99].  Therefore, this
        specification requires a large minimum RTO as a conservative
        approach, while at the same time acknowledging that at some
        future point, research may show that a smaller minimum RTO is
        acceptable or superior.

Given that Linux, BSD etc use 200 milliseconds, not 1 second I am
wondering whether there has in fact been any research done as
mentioned in last sentence. It seems a very high timeout especially on
two locally connected devices.

Apologies if I'm asking on the wrong list.

Regards,

Ian

-- 
Web1: http://wand.net.nz/~iam4/
Web2: http://www.jandi.co.nz
Blog: http://iansblog.jandi.co.nz

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