Interoperability, internetworking and quality of service in satellite networks

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Title of the proposal: Interoperability, internetworking and quality of service in satellite networks

Tutor: Prof. Maurizio Casoni

The ever increasing popularity of hybrid networks, i.e., networks that have both terrestrial and wireless links, reveals that they will play a crucial role in future infrastructures for multimedia applications. Indeed, one of the most challenging issues is to provide a seamless service provision across different networks and, in particular, to evaluate end-to-end performance for wired/wireless customers, slow or fast moving. For instance, a network inside a quick moving vehicle, such as a train, can be connected to the terrestrial network via one or more satellite links; analogously, a Wi-Max network could deploy a satellite back-haul towards a wired high-speed backbone. In this scenario broadband satellite links play a significant role because of their many advantages: global coverage, bandwidth flexibility, reliability and multicast capability. On the other hand, Internet and the related TCP/IP protocol suite have definitely become the leading solution for wide area data internetworking and the study of their performance in networks combining wired and wireless links is crucial. However, TCP performance degrades in networks with long propagation delays and relatively high link error rates such as satellite networks: TCP assumes congestion in the network as the main reason for packet losses and delays and if these are caused by something else, as in the wireless case, its performance dramatically decreases. Moreover, since IP is the reference at network level, DiffServ and IntServ architectures for IP QoS have to be investigated, with the goal of determining the best network utilization with the greatest number of satisfied customers. In essence, network models for quality of service must be developed and refined, to successfully accommodate multimedia service provisioning. Overall, the analysis of all issues related to end-to-end quality of service, taking into account the interplay between both the internet and transport layers and the underlying MAC/physical levels, is strategic in hybrid scenarios of wired (Gigabit Ethernet/optical networks) and terrestrial wireless (3G/4G/Wi-Fi/Wi-Max) connected to satellite links, Also, mobility has to be carefully considered, since an ever increasing number of users is asking not only for high-speed and ubiquitous connectivity, but also for “on-the move”, seamless connections.