[e2e] What's the benefit of out-of-order processing?

[David P. Reed]

At 10:20 AM 9/18/2001 -0400, Naidu, Venkata wrote:
>-> Congestion control is useful, but it is not an "application
>-> benefit" (at
>-> least directly).  Out of order delivery has *nothing* to do
>-> with whether
>-> congestion control signals are sent, or how their coding (as ACKs or
>-> whatever) reflects their meaning.
>
>    Reed, I agree that "Out-of-order" is nothing to do with Congestion
>    Control. But "delivery" (our-of-order or in-order) has close relation
>    with Congestion Control. How else will the sender know without
>    receiver sending back some signals to pace the sender?

True.  But those signals don't have to be "acknowledgments" - the "entropy" 
of packet-by-packet acknowledgments as congestion control is very low, by 
simple inspection of their statistics.  Most ACKs contain only a tiny 
fraction of a bit of congestion-control information, as an entropy measure. 
Efficient coding of congestion control signalling would not transmit such 
messages, and would focus on the information-packed messages that occur 
when congestion is imminent or occurring.


>    You mean to say in the FTP example, we can do congestion control
>    with time outs than expecting signals from receiver.
>
>--Venkata Naidu