Multi-hop Coflow Routing for LEO Distributed Computation Satellite Networks.

The low earth satellite networks are envisioned to be an indispensable part of next-generation network due to the seamless Internet access. Deploying distributed computation into LEO satellite networks can decrease the latency of transmitting satellite-terrestrial computing jobs, which is crucial to expanding the service capability. Distributed computation depends on the exchange of data flows between worker nodes, as a type of concurrent and interrelated flows called coflow. However, the mesh-shaped topologies of LEO satellite networks make coflows prone to bandwidth competition on multi-hop links, which impedes the efficiency of distributed computation. In this paper, we formulated the multi-hop coflow scheduling process in LEO satellite networks as a routing and bandwidth allocation problem. Then, we simplified the problem to a coflow routing problem, and proposed the coflow routing greedy scheduling (CRGS) algorithm on the basis of the characteristics of multi-hop networks. Finally, we simulated in an SDN environment, where CRGS was deployed in an SDN controller. Compared with several existing algorithms, the CRGS algorithm is proved to reduce the coflow completion time (CCT) more effectively.