scMPTCP: SDN Cooperated Multipath Transfer for Satellite Network With Load Awareness

Satellite networks are multilayered, and the number of satellites in a single constellation is also increasing. These characteristics make satellite network more suitable for multipath transmission like multipath transmission control protocol (MPTCP). With the use of MPTCP, the bandwidth of different satellite channels can be aggregated, and the mobility performance of users can be improved. Furthermore, software defined networking (SDN) is introduced to the MPTCP to solve the shared bottleneck problem. However, the performance of existing scheme is still far from optimal. The main problems include: (1) static number setting of MPTCP subflows on a per host basis and (2) unaware of the traffic load during the subflow route selection. The shared bottleneck problem is more serious in the satellite network with lattice-like topology. To solve the above problems, we propose an sdn cooperated MPTCP (scMPTCP) architecture and its related algorithms. We extend TCP options to piggyback the relevant control information to flexibly support the communication between the subflows of transport layer and SDN controller. Then, we propose a load and shared bottleneck aware subflow route selection algorithm and adjust algorithm. These two algorithms select routes for new subflows based on the available bandwidth of each route and avoid the bottleneck of other subflows, and also can adapt to the changes of network load. We implement the scMPTCP and its algorithms. The evaluation results show that compared with searching over the non-overlapping paths or shortest paths schemes, our scheme can achieve much higher total system throughput. Moreover, by adjusting the subflows which share bottlenecks, the total aggregated throughput of that connection is also improved greatly.