Abstract: With the explosion of the internet traffic, the IPbased large volume data transmission provided by satellite network becomes a prerequisite to integrate satellite network and terrestrial network. Onboard router，whose transmission rate and QoS (Quality of Service) determine the throughput and efficiency of the entire network，is the key facility of the satellite network. Based on the low throughput of existing onboard routers, a design of high speed onboard router for LEO (Low Earth Orbit) satellite constellation is proposed. Implementing dynamic routing into the snapshotbased routing scheme makes it possible to minimize packet drop when link failure happens. This scheme enables iterative data switching after one time route computing. By using sharedmemory mode to build switchingmemory unit, also with Spacewire and Serdes interface units deployment, the intersatellite throughput can achieve up to 51 Gbit/s in theory. Moreover, the onboard router supports IPbased transmission, which lays the foundation for integrating with terrestrial network.

Key words: satellite onboard router, LEO constellation, throughput, IPbased, dynamic routing