Packet loss in TCP hybrid wireless networks

Hybrid networks where packets travel through both a geostationary satellite and a terrestrial local wireless link are a particularly challenging environment with respect to TCP performance. The reason is that such networks exhibit both a high latency and a high packet loss, a combination that stresses TCP's congestion avoidance algorithm. Accurate modelling of the packet loss process in such networks is not an easy task, so very simplified models are frequently used. We start from channel state measurements done on a fixed-speed IEEE 802.11 terrestrial channel and we use the ns-2 simulator to evaluate the performance of TCP on it. We then evaluate the accuracy of some models that are commonly used to represent the channel state, by comparing these models with actual traces.