Buffer control strategies for the transmission of TCP flows over geostationary satellite links using proxy-based architectures

In this paper we consider the transmission of TCP flows over networks including geostationary satellite links. In this environment, due to the large delays and to the possibly high error rates introduced by the wireless channel, special protocols and architectures are required to obtain good performance. Our main goal in such a context is to efficiently manage the buffers that are usually placed between the cabled and the wireless part of the network (C. Barakat, et al., 1999) in order to harmonize the different bit rates that may be available over these different links. Many approaches based on proxies (J. Border, et al., 2001) (T.R. Henderson and R.H. Katz, 1999), in fact, buffer TCP flows immediately before the wireless channel access and use dedicated transport protocols to optimize the transmission over the wireless links. However, while many contributions focus on the overall system performance and on the problem of maintaining the end-to-end semantic when TCP is terminated at proxy nodes, very few of them deeply investigate how buffers are to be managed in order to avoid congestion/losses while still be able to achieve good performance. This contribution is therefore aimed at filling this gap, by presenting buffer management techniques and evaluating them against previous solutions (M. Marchese, et al., 2004).