[e2e] Number of persistent connections per HTTP server?

David P. Reed dpreed at reed.com
Tue Oct 15 07:41:38 PDT 2002


At 07:02 AM 10/15/2002 -0700, Jim.Gettys at hp.com wrote:

>So discussing ways that congestion control can be improved is clearly
>on topic for this list.

All I did was object to an incorrect idea: that TCP _assumes_ one 
connection per application.

Congestion control (especially endpoint-based) should be very much on-topic 
for this list.

As for HTTP 1.0's multiplexing of single TCP connections - it seemed 
well-thought-out given the constraints.   But I wonder if the best scheme 
would have been to construct a protocol replacement for HTTP that was not 
built on TCP, but instead on datagrams, where the "new HTTP" implemented a 
TCP-compatible congestion control scheme on the overall datagram flow, 
while keeping state for longer than an individual transaction and allowing 
concurrent "GET" commands to proceed without artificial ordering constraints.

This would avoid the "slow start" and connection establishment overheads 
(by combining the flows into a single bundle for the purpose of congestion 
management), while maximizing concurrency at the endpoints.  ECN, RED, and 
window-based congestion control would work fine, actually BETTER.

Such a protocol would be extremely useful for things other than HTTP, too.






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