> TCP is still bursty over high bandwidth-delay product links while inflating
> the congestion window. Basically everything in the window is trasmitted at
> once, and when ACKs arrive, the process repeats with a larger window. Thus
> larger windows cause the burstiness to proceed for longer amounts of time.
What do you mean by "trasmitted at once?" TCP does not send the whole window
all at once. Do you mean the case when after the link is idle for some time,
TCP can send the whole window at once? I think this has been discussed before
and the problem is an implementation bug. Joe Touch has a note on this.
Or do you mean something else? Note that congestion window (cwnd) is inflated
based on incoming ACKs. The rate of increase is determined by the rate of
incoming ACKs. And for every ACKs, it can send up to 3 segments. This is
the burstiness. And cwnd is reduced back to 1 (or 2 or 3 segments depending
on whether the implementation uses larger slow start cwnd) after the link is
idle.
One exception is when there is segment dropped. But as I mentioned
previously, I think it is not as bad as it used to be. There are other
issues, say ACK compression, ... But I think a larger window does not make
this worse than before. Please elaborate.
K. Poon.
[email protected]
This archive was generated by hypermail 2b29 : Thu Feb 24 2000 - 22:18:57 EST