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Dear Sally (CCing to the
DCCP mailing list too), Further to our offline conversations
regarding calculating the receiver rate after long idle periods, where the
3448bis clearly states that the receiver rate is calculated only for R_m
seconds where R_m is the receiver’s estimate of the RTT, I noticed that
this is not the case in the ns-2 tfrc-sink.cc code (ns-2.29). In the est_thput ()
function: if ((rtt_ > 0) &&
((now - last_report_sent) >= rtt_)) { // more than an
RTT since the last report time_for_rcv_rate
= (now - last_report_sent); if
(rcvd_since_last_report > 0) { thput =
rcvd_since_last_report/time_for_rcv_rate; cout
<< time_for_rcv_rate<<endl; } } Here the time_for_rcv_rate considers the entire idle period
rather than 1 RTT. This concurs with why the inflation factor in the receive
rate length came into enforce for FR for TFRC. The DCCP CCID 3 code in ns-2 is
also based on this, hence the receiver is reporting a receive rate calculated
over the entire duration of the idle period. This has to be corrected? Regards Arjuna ------------------------------- Dr.Arjuna Sathiaseelan Electronics Research Group Email: arjuna@xxxxxxxxxxxxxx Web: www.erg.abdn.ac.uk/users/arjuna Phone : +44-1224-272780 |
