[e2e] 10% packet loss stops TCP flow

Vishal Misra misra at cs.columbia.edu
Sat Feb 26 03:02:51 PST 2005

There is another very simple way to look at it. The most 
"optimistic" model of TCP, that only looks at congestion 
avoidance (AIMD) and ignores slow start, timeouts etc., predicts 
the following relationship between the average window size (w) 
and loss probability (p):

	(w^2)*p = 2

Note that this is _independent_ of link bandwidth and RTT. So 
with a loss probability of 10%, the average window size is going 
to be of the order 4. If you factor in other protocol details, 
the number will be even smaller. With a window size of 4 or 
below, fast recovery will not work and any loss will lead to a 
timeout (for the average connection). Hence loss rates of the 
order 10% simply will not work, irrespective of RTT/link bandwidth.


More information about the end2end-interest mailing list