A Multicast Routing Algorithm For GEO/LEO Double-Layered Satellite IP Networks

Satellite networks have played an important role in providing multicast services for its ability of wide coverage. In the composition, different orbit satellites networks have different characteristics. Multilayer satellite network can realize the complementary advantages of different orbits satellites, not only improve the utilization of bandwidth, but also improve the performance of network and anti-destroying ability.Currently, GEO/LEO double-layered satellite network has become a hot topic. The higher satellites can use its large storage capacity to assume management of the whole network; it also can transfer data as a backup of lower satellites. The latter can reduce the link failure rate caused by unexpected problems such as node failure and link failure. The lower satellites mainly responsible for transfer packets thanks to its low delay. GEO/LEO double-layered satellites network, not only can combine each layer satellites’advantages, improve the space spectrum utilization, but also have the ability to anti interrupt, improve the whole network performance.The high bandwidth characteristics of satellite channel make it become a ideal carrier of multicast service. Multicast technology can realize "one to more" transmission, save network bandwidth and reduce network load. One of the key techniques for satellite multicast communication is to build a good performance multicast tree. For satellite communication network, there exist many problems of limited resource, high link bit error rate and fast changing of network topology. Therefore, combining LEO satellites’ advantages on transmitting real-time information with GEO’s ability of big computing, a GEO/LEO Double-Layer Multicast Routing Algorithm is introduced. Simulation results demonstrate that the performance benefits of the proposed DLMRA in terms of the tree delay, the bandwidth cost and packet loss rate by comparison with the other algorithms proposed before.The satellite networks may meet unexpected issues such as node failure or link failure, especially for LEOs. Thus, the GEO satellite layer could be a backup for LEO satellites layer to forward data, and the algorithm should be improved on this basis, can reduce the packet loss rate caused by those unexpected problems, improve the performance of the whole network.