Ef-OFDP: An Efficient OpenFlow-based Topology Discovery Protocol for SDN

To address the issues of high control plane load, excessive redundant traffic, and topology update delays in traditional topology discovery protocols in SDN, this paper proposes an optimized mechanism, Ef-OFDP. By integrating the Minimum Vertex Cover (MVC) algorithm and Bidirectional Forwarding Detection (BFD) technology, Ef-OFDP constructs a dual-layer probing architecture comprising covering switches and ordinary switches, and integrates BFD to enable dynamic awareness of link states and trigger events, thereby reducing the overhead of periodic LLDP packets. Simulation experiments validate Ef-OFDP’s performance in heterogeneous topologies (tree, linear, Fat-Tree). Results demonstrate that compared to OFDP and OFDPv2, Ef-OFDP achieves over 50% efficiency gain in total volumes of Packet-Out and Packet-In messages, with even more pronounced benefits in large-scale networks. The solution in this paper provides a low-overhead and highly responsive topology discovery method for SDN scalability bottlenecks, suitable for dynamic scenarios such as data centers and distributed edge networks.