[e2e] Switched Ethernet is Not an End-to-End System; was Protocols breaking the end-to-end argument

Bob Braden braden at ISI.EDU
Sun Nov 1 10:01:26 PST 2009

Jon Crowcroft wrote:
> well to be specific,
> TCP retransmission times
> and 
> TCP congestion control
> were NOT designed in from day 1


It does not really matter, of course, but your quick summary is not 
quite accurate.
It depends upon what you consider to be "Day 1".  E.g., RFC 793 did NOT 
have a
fixed retransmit time.  And if you want to give RSRE credit for 
exponentially smoothed
RTT measurements (a fact I had forgotten, assuming you are correct), you 
ought to
give Van credit for finally figuring out how to do real congestion 
control, in 1987.

Bob Braden
> early TCPs had fixed retransmit until the RSRE algorithm
> and then it was still some time before the Karn/Partridge
> improvements kicked in
> plus 
> early TCPs had no congestion control at all 
> until '87

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