Cross-Layer Enhancement to TCP Slow-Start over Geostationary Bandwidth on Demand Satellite Networks

Abstract. It is well-known that the transmission control protocol (TCP) does not perform well in wireless and satellite environments. We investigate the use of cross-layer design involving the transport and medium access control (MAC) layers in the context of a geostationary bandwidth-on-demand satellite network to simultaneously enhance TCP performance and to improve bandwidth utilization. In this paper, we focus on the slow-start phase of the connection. In essence, we create a bandwidth pipe between the two layers so that through cross-layer interactions, the TCP connections are aware of the satellite resources available to them, thus adjusting their congestion window accordingly. Our proposal includes minimal changes to the original protocol, allowing easier integration and inter-working with existing infrastructure. Our evaluation results show a shorter slow-start duration with better bandwidth utilization. Although the performance gain is higher in a lossy satellite link, we also found that it is dependent on the network load. Keywords: Cross-layer design, satellite network, bandwidth on demand, TCP.