Towards Scalable and Flexible Path Control Schema in Software Defined Networking

Software defined networking is attracting extensive attention to achieve better network performance through flexible flow path control. However, traditional OpenFlow-based forwarding method faces practical challenges such as limited flow table size and dynamic flow path setup. In this work we propose a scalable and flexible path control schema based on source routing to address those problems through pre-installing flow paths into the data plane and inserting path information into the packet header at the network edge. To reduce the flow table overhead, we assign an ID to each path and aggregate IDs by wildcards. We formulate the path ID assignment problem and decompose it into the link ID assignment problem, which is solved by our proposed heuristic algorithm based on vertex coloring and topological potential. Extensive simulations on various topologies show that our proposed algorithm can reach the optimal solutions in most topologies within the time limit, and our path control schema can save more than 98% rules compared with traditional OpenFlow-SDN method and has good universality. In addition, our method can achieve better performance in terms of dynamic flow path setup due to the characteristic of source routing.