On Dynamic Routing Technology for Space Network

Since the topology of space network is time-varying, dynamic routing is a key technology to realize networked space system. In this paper, a typical link state routing protocol, i.e. OSPFv3, is chosen as the dynamic routing protocol for space networks and two improvements have been adopted to alleviate the high protocol overhead and slow routing convergence problem of OSPFv3 when directly applied to space network. Firstly, we analyze the characteristic of space links and conclude that point-to-point network type can reduce protocol overhead. Secondly, we introduce the decoding lock flag of the links to the detection process of link state change to quicken the routing convergence process. Then, the improvements for OSPFv3 protocol are implemented on a space router and the architecture of the space router is introduced. Finally, we conduct three tests to evaluate the performance of the implemented OSPFv3 protocol. The performance evaluation results show that the implemented OSPFv3 protocol is compatible with terrestrial COTS router. The response delay of local link state change is about 192 ms. The onboard route computation overhead is less than 17 ms in a 5 node network on a 64 MHz SPARC processor.