SDN-Based End-to-End Fragment-Aware Routing for Elastic Data Flows in LEO Satellite-Terrestrial Network

The wide coverage of satellite networks and the large bandwidth of terrestrial networks have led to an increasing research on the integration of the two networks (ISTN) for complementary advantages. However, most researches on routing mainly focus on the internal routing of the satellite network. Due to the point-to-area coverage of the channel characteristics between the satellites and the ground stations, the heterogeneity of ISTN has increased, which makes that the routing algorithm of the traditional satellite networks cannot be applied to the end-to-end routing of ISTN. Meanwhile, the data flows with elastic quality of service attribute make the routing pre-assign and resource allocation in ISTN much more complicated, which has been rarely researched before. In this paper, we first describe the unified network architecture based on software-defined network and model the data flow. Then, based on the considerations of latency, capacity, wavelength fragmentation, and load balancing, a heuristic service-oriented path computation algorithm for elastic data flows is proposed for the complex heterogeneity of the ISTN. The simulation shows that, the end-to-end routing mechanism can reduce the blocking rate of the ISTN, and our proposed algorithm greatly reduces the wavelength fragmentation and bandwidth consumption, and has a better performance on load balancing, with a slight disadvantage in latency when the network load is high.