[e2e] Simple Question on TCP Window Size

David P. Reed dpreed at reed.com
Wed May 9 12:54:27 PDT 2001

At 12:07 PM 5/9/01 -0600, Vernon Schryver wrote:
>It sounds more plausible to use ECN bits to inform applications such as
>streaming UDP audio or video, but on reflection, they don't sound much
>better.  Such applications necessarily have some reverse traffic to tell
>the sender to continue sending.  That reverse traffic ought to tell the
>sender about more than the effects of congestion.  The sender would better
>adjust its stream not just for what ECN can say but also for jitter, delay,
>and packet losses unrelated to congestion,
>ECN sounds great, but let's not oversell it.

I was focusing on things like streaming audio and video because they *do* 
need congestion information, and they contribute significantly to congestion.

RED and ECN provide useful congestion signalling from the network to the 
endpoints.  Since closed-loop control exists for streaming audio and video, 
these signals can be part of the input (along with ordinary drops) to the 
streaming control loop.  Properly done, it will make them more 
"tcp-friendly" than they currently are (many of the streaming services 
don't even think of packet drops as possible congestion and throttle back).

Wasn't at all trying to oversell - I assumed that DNS would not benefit.

- David
WWW Page: http://www.reed.com/dpr.html

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