[e2e] TCP in outer space

Alex Cannara cannara at attglobal.net
Thu Apr 12 10:35:40 PDT 2001


My comment is simply intended to reflect the plain fact that since 1978,
there has been no mystery that, for instance, TCP's retransmission
algorithm has been given no means to distinguish among even the two most
important causes of loss -- physical or queue drop.  

The history of TCP and 'congestion control' has been to burden the
former with responsibility for the latter, without:  a) providing
accurate information to allow engineered control; and b) without
addressing the same need for congestion control for other base
protocols, such as UDP.  Automotive, aircraft, marine, even toilet
systems are judged inadequately designed without proper control.

The recent vignette on "Why UDP has a length" illustrates some of my
point -- ad hoc attention to networking.  We all know the Internet's
near disasters some years ago moved folks to pick TCP to do path-
congestion control, sacrificing its performance under physical loss. 
This is another plain example of the ad-hoc approach that has
unfortunately characterized some Internet designs.

I'll repeat the point:  nothing in 2001 is new with respect to Internet
design criteria, that was not evident to network engineers in and out of
the Internet community over a decade ago, yet the discussions of what to
do play the same old tunes.  If the old tunes were spur-of-the-moment
(ad hoc), as we know some significant ones were, then why be so
resistant to new ideas for a new networking realm?  Bureaucracies are
resistant.  Productive, competent research cannot be.


Bob Braden wrote:
>   *> All the discussion on ECN, etc. also demonstrates how little thought was
>   *> given, over many years, to addressing fundamental networking realities
>   *> that have nothing to do with a particular protocol, but a lot to do with
>   *> all protocols.
> Alex,
> This is not only completely false, it maligns the highly competant
> individuals who have worked these problems over the years.  Do you
> in fact have a useful and correct point to make?
> Bob Braden

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