Interworking with TCP/IP protocol suite in Skyplex Satellite Networks

The growing development of standard Internet services and the emerging exploitation of novel multimedia IP-based services, in the last years significantly have promoted scenarios where Satellite Networks (SN) can play crucial roles. The basic role covered by Satellite Networks is characterized by their native features, namely broadcasting capability, large coverage area and high data rate links. Among t e operational SNs, the Skyplex Satellite Network (SSN) exploits an innovative Alenia Spazio technology now embarked on several satellites (e.g. HB, W3A): the Skyplex on-board multiplexing. The Skyplex multiplex allows a decentralised management of the uplink communication resources, by providing broadcasters and Internet Service Providers (ISP) with direct access to the satellite transponder via Earth Stations (ES) co-located into their network domains, without using third-party hub stations facilities. Likewise, final End Users (EU) can get straight access to the satellite communication resources through two-way Satellite Terminals (ST). In this perspective the interworking with terrestrial networks based on Internet Protocol (IP) occurring both at STs and ESs is a key point to allow a seamless and efficient transport of IP traffic on SSN links. The work presented in this paper has been carried-out in the framework of the ESA ARTES 3 – Line 1 program. First, it provides a description of the architectural design of the Inter- Working Unit (IWU) of Skyplex STs and ESs, with emphasis on the interworking features necessary to effectively handle IP flows in the SSN domain. Finally, novel mechanisms conceived to boost the performance of Transmission Control Protocol (TCP) when TCP sessions are carried on Skyplex satellite links are discussed.