[Info-vax] Accuweather new contract

[JF Mezei]

On 15-03-30 09:19, Bill Gunshannon wrote:

> That has always been the case with the TCP/IP spec.  I can't imagine
> why any implementation would not have been taking advantage of this 
> unless it was just plain broken.

A geeky friend said some time ago while testing newly introduced cable
speeds that he could not achieve the 20mbps download with only 1mbps
upload on Windows but could on Linux due to Windows sending acks for
every packet. (those acks require more than 1mbps in upload).

Cable did impove advertised upload speeds with DOCSIS-3 to provide
sufficient upload bandwidth to make use of higher download speeds.

Note that I have never really checked this myself.

While the specs for TCP have always said that an ACK conforms receipt of
all bytes up to and including what the ACK is for (which means all
packets before it that may nopt have been acked), it does not mean that
stacks have been smart enough to monotor throughput and realise that
they can ACK every second packet for instance.

Another aspect that varies from stack to stack is the TCP windowing.
The specs dictate the sender abides by the window size set by recipient,
and that when a packet has been declared unreceived, the widnow size is
halved, but it gives the recipient plenty of flexibility to set the
window size.