[ns] Need Help for TCPAgent::rtt_update()
teerawat at ece.ubc.ca
Wed Jun 27 09:20:44 PDT 2007
I have a question in regards to function rtt_update of class TcpAgent.
Here is the code:
================= BEGIN CODE =================================
void TcpAgent::rtt_update(double tao)
double sendtime = now - tao;
sendtime += boot_time_;
double tickoff = fmod(sendtime, tcp_tick_);
printf("sendtime = %2.4f, boot_time_ = %2.4f, tickoff =
t_rtt_ = int((tao + tickoff) / tcp_tick_);
================= END CODE =================================
Why can't we use 'tao' as an RTT sample? Why do we have to consider
"boot_time_" ? It seems like "tickoff" is the offset which helps
line up tao to the end of "tcp_tick" after "boot_time_" is
considered. But why do we need to consider "boot_time_".
Thanks a lot.
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