Study On IP Routing Algorithm And Improvement Of TCP For Double-layered Satellite Networks

As a new research field, more and more attention has been paid to satellite-networks. Currently, the research on routing algorithm of satellite-networks is still in an early stage. Due to the special characteristics of satellite networks, such as dynamic topology etc, routing algorithms working in terrestrial networks do not fit satellite- networks. The routing algorithm of the satellite-networks will directly influence the performance of the whole communication networks and the quality of communications, so it's necessary to develop a new routing algorithm, which is tailored for satellite- network as to its special characteristics.After the analysis of the existing routing algorithms of satellite-networks and the difference between satellite-networks and terretrial networks, a double-layered satellite-networks routing algorithm DSRA is proposed in the thesis, and the OPNET simulation implementation of DSRA is also presented. Based on the simulation, a performance evaluation of DSRA is given by experiments.TCP experiences performance degradation in satellite-networks due to high BER, high latency and bandwidth asymmetry, so it is necessary to improve TCP for satellite-networks. TCP flow control is the basis for the Internet to operate normally, and the TCP flow congestion control is one of the current hot problems in the Internet research. In this thesis, an improved scheme based on the research of TCP-Westwood is prosed and the result of OPNET simulation show the validation of the scheme.