PS: again, from my previous email - this is still off-topic
for DCCP, but still unanswered (and I'll move the question
to RMT in a few days if nobody reacts): why was RTO
replaced with 4 instead of 4*RTT in TFMCC?
I am not a co-author of TFMCC, so I don't know all of the
design decisons.
The response function in RFC3448 (TFRC) is as follows:
s
X = ----------------------------------------------------------
R*sqrt(2*b*p/3) + (t_RTO * (3*sqrt(3*b*p/8) * p * (1+32*p^2)))
By using b=1 and t_RTO=4 RTT, you get the following:
s
X = ----------------------------------------------------------
R*(sqrt(2*p/3) + (12 *(sqrt(3*p/8) * p * (1+32*p^2))))
(Note the parentheses after R in the denominator.)
The response function in TFMCC is as follows:
8 s
X = ---------------------------------------------------------
(1)
R * (sqrt(2*p/3) + (12*sqrt(3*p/8) * p * (1+32*p^2)))
This looks to me the same as the response function for TFRC,
with b=1 and t_RTO = 4 RTT, but mutliplied by a factor 8.
(Given that X is the transmit rate in bytes per second, I don't
see why the factor of 8 is ok. But it does use t_RTO = 4 RTT.)
- Sally
http://www.icir.org/floyd/
