Pre-rerouting Strategy to Ensure Business Continuity for Low-Earth-Orbit Satellite Network

In a satellite network, due to the relative movement between satellites in different orbits or different layers, the intersatellite link changes dynamically. These changes are further classified into 2 main groups: some of them are predictable, such as link interruptions caused by changes in the relative positions of satellites in different orbits or different layers, while others are unpredictable, such as link interruptions caused by cosmic rays in the free-space environment, effects of the solar wind, or damages to satellite equipment. Such intersatellite link interruptions will cause severe service interruptions. For predictable link interruptions, this study proposes a pre-rerouting strategy based on the extended Open Shortest Path First protocol where a new label switching path (LSP) is built and services are switched to the new LSP before the old LSP is interrupted. In this case, the packet loss rate will be substantially reduced, ensuring a high degree of service continuity. In a performance verification experiment, simulation results show that the packet loss rate decreased by about 6% compared with that of the traditional rerouting strategy.