Comments below......
"Priscilla Oppenheimer" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> At 10:01 AM 7/10/01, Peter Slow wrote:
> >i think this is because the window size is allowed to get much larger
> >befrore something gets dropped on a higer speed segment.
>
> Would a TCP recipient know it was on a high-speed segment, though? A
sender
> might have some idea because it tracks congestion, but not the recipient.
IT seems to me, tho, that the receipient only sends an ack based on the
window size it is told to use by the sender. Therefore, on a high speed
connection, the send doubles it's windows size (and therefore doubles the
amount of packets that can be recieved by the receiver before an ACK) until
it hits congestion (the speed limit).
For instance, starting at one (S = Sender, R = Receiver)
S -> pack1 -> R
S pack2 -> R
S -> pack3 -> R
S pack4 -> R
S -> pack5 -> R
S -> pack6 -> R
S -> pack7 -> R
S <- ACK7 <- R
and so on......
Since TCP doubles its window size after each successfully ACK, the receiver
only needs to ack after a "window full" of packets are received (assuming
they all get there). When the TCP windows gets so large to overwhelm the
link (anywhere in the path), it halves the window size and congestion
avoidance takes over, etc.... so it would make total sense on a high speed
link that you'd see many less acks because the TCP window size may be
bouncing between 32768 and 65536 packets per ACK instead of 128 and 256
packets per ACK.
My 2 cents......
Mike W.
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=11835&t=11703
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