LISP-LEO: Location/Identity Separation-based Mobility Management for LEO Satellite Networks

In space-terrestrial integrated networks, the relative motion between LEO satellites and ground terminals is inevitable, which will trigger the reassignment of the terminal IP addresses and disrupt the ongoing TCP connections. Traditional Mobile IP protocol can solve the problem by using the home agent and the tunneling mechanism. However, for space-terrestrial integrated networks, Mobile IP is inefficient as it introduces (1) increased latency when registering with the remote home agent, (2) high packet loss due to large registration latency, (3) triangular routing to the remote home agent. To address the above issues, we propose LISP-LEO, a location/identity separation-based mobility management protocol for LEO satellite networks. Specifically, (1) we divide the Earth's surface into partitions and maintain a partition-satellite mapping table in real-time according to the regularity of satellite motion, (2) we always route traffic to the satellite above the destined terminal by querying the partition-satellite mapping table, which eliminates triangular routing and the related performance overheads, (3) we handle the corner case that multiple satellites occur above the destined terminal by proposing last-hop relay. The evaluation convinces that, for the LEO-48 constellation, LISP-LEO produces a 55.0% reduction in the RTT and a 45.8% reduction in the number of forwarding hops in the worst routing case compared with Mobile IP.