An efficient flow table consistent update scheme for software defined network

Network updates can result in some problems such as lost connectivity and forwarding loops in the network. To solve the network update problems, the update consistency abstraction is proposed in SDN. OpenFlow is an effective solution for SDN and the update consistency in OpenFlow network is the consistency of the flow table updating. However, the update schemes proposed recently have high TCAM usage or high controller workload. The TCAM memory at switches is fundamentally limited and the controller is the core part of SDN. In this paper, a flow table update scheme called Time Stamp Packet Based (TSPB) is proposed to solve the problem of flow table update consistency based on OpenFlow. The correctness of the consistency of TSPB scheme is demonstrated in the view of logic. At last simulation results testify that proposed scheme TSPB can reduce TCAM usage with less update completion time and controller workload.