IP Satellite Network Architecture for Effective TCP Performance

ABSTRACT: Satellite networks provide high bandwidth global communications without relying on existing infrastructure. Current satellite system use is impeded by round trip delays and limited ground access points. Future IP based LEO/MEO satellite networks offer smaller delays and flexible, high capability communications. Propagation delays, highly dynamic links, higher error rates, dynamic satellite access points for ground and airborne users, potential satellite losses, and limited Onboard processing capability all challenge current routing and TCP protocols. In this project we extend routing algorithms, develop new TCP methods, and use DTN methods to surmount these problems. The TCP methods are designed to be compatible with IPSec and do not require changes in existing TCP modules. In Phase I, we start with widely cited IP LEO/MEO satellite network algorithms developed by academic partner Prof. E. Ekici of Ohio State University and TCP methods from other SSCI projects. In Phase II, we extend the Phase I algorithms, and throughly characterize their performance. Prof. Ekici's expertise in satellite routing and satellite network capabilities and architecture, combined with SSCI's work in applying DTN methods and improving TCP effiency in wireless networks will ensure a successful Phase I feasibility demonstration and development of effective methods in Phase II. BENEFIT: The protocols developed in this effort will be suitable for inclusion in future IP-based military satellite systems. The TCP and other protocols developed in this effort do not assume that IP headers can be read in the interior of the satellite networks; Instead they use information obtained from queries to routing modules (using metric and other data collected and distributed through the routing modules). Specific header information is used only at the network edge and the queries do not directly obtain network topology information. These features will help ensure compatability with IPSec and other security measures in military networks. The measures will improve performance in emergency networks and other wireless networks subject to interference, unreliable communications nodes, power limitations and intermittent outages.