PASR: An Efficient Flow Forwarding Scheme Based on Segment Routing in Software-Defined Networking

Software-Defined Networking provides flexible and efficient network management. However, the limited flow table space lead to many challenges for SDN networks on flexibility and scalability. In order to achieve efficient routing scheme, we propose an efficient flow forwarding scheme based on Segment Routing named PASR to solve SDN switch flow table resource shortage problem. Traditional OpenFlow-based or MPLS-based flow forwarding scheme may lead to performance degradation due to flow-table overflowed or heavy MPLS label load incurred. PASR exploits SDN, Segment Routing and intelligent path encoding algorithm to achieve a trade-off between flow table resource and MPLS label load. The proposed PASR can learn the flow path information online to implement path aggregation by aggregating a large number of flows into a small number of flow entries based on the coincidence degree of the flow path. To find the optimal flow path aggregation scheme, we present an intelligent encoding algorithm to maximize the overall cost saving. The simulation results show that PASR can effectively reduce both the number of flow entries and the MPLS label load of the packet.