[e2e] Question regarding duplicate threshold values based on cwnd

Arjuna Sathiaseelan arjuna.sathiaseelan at gmail.com
Mon Jul 4 13:45:06 PDT 2005


Dear All,
 I have been reading several papers on improving TCP performance in
the presence of packet reordering and all of them say that when the
packet is assumed to be reordered, the duplicate threshold is
increased upto a cwnd of packets. But is it right to use cwnd as the
maximum limit. Assume this scenario:

In ns-2 implementations, the cwnd grows bigger than the receiver
window..thus if the sender's cwnd is 50  and the receiver window is
only 20, that means the sender can send only 20 packets..Thus if a
packet has been reordered, the sender's dupthresh value would be 50
rather than waiting for the 20 packets. That means the sender is
waiting for a large number of packets than it has sent. So would it be
better to have the dupthresh values based on the sending window rather
than the cwnd? I am not sure if I am making sense, but its just a
question thats been lingering on my mind for a long time..Please
pardon me if this question doesnt make any sense :).

Regds,
Arjuna


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