[e2e] TCP Performance in Satellite Networks

[Arjuna Sathiaseelan]

Dear All,
  I am a PhD student and am testing the performance of TCP on
Satellite Networks when packet reordering occurs. I am a novice, so please
excuse me if somethings are irrelevant. I perform reordering
by normal distribution and packets are delayed in the range of 0ms to
200ms. This error module was attached to all the satellite nodes. I use an
Iridium constellation network. I perform experiments for 100s. The maximum
congestion window was set to 500.

>From what I see is that when I use Sally Floyd's RR-TCP and TCP DSACK -
the performance was similar to standard TCP SACK. DSACK's were generated
and received successfully but the restoration of the congestion window
upon false retransmits never took place!! Even though I had a high maximum
window size, the congestion window grew only upto 10 segments.

Moreover when I increase the dupthresh values (to 4,5,6), I see more
timeout events, so I guess increasing the dupthresh values when reordering
occurs is not the right way since it leads to more timeouts because of the
large RTT. Am I right? I would like to know why does RR-TCP and DSACK have
no impact on the performance. Has anyone tested the performance of both
the protocols on a Satellite environment? I would be very much obliged if
someone could clarify these doubts please.

Regards,
Arjuna