Simulation Study of TCP Performance in TRANSAT Satellite Architecture

The TRANSAT [1] satellite architecture is intended to provide efficient Internet access services over DVB-RCS satellite links. One of the key features in the TRANSAT architecture is the Satellite-Link Aware Communication Protocol (S-LACP), which operates at the link layer, and is employed over a satellite segment to decrease the residual packet error rate down to an acceptable level. In this simulation study, we measure the TCP performance over satellite links, including the effect of various TCP enhancements and the S-LACP protocol. We show that when S-LACP is used to reduce the residual packet rate as seen by the TCP layer, performance improves. Without S-LACP the modeled packet error rate tends to be rather high not allowing a TCP sender to open the congestion window large enough or later on to retain the congestion window fully open.