SDN Migration: An Efficient Approach to Integrate OpenFlow Networks with STP-Enabled Networks

Software Defined Networking (SDN) is a paradigm shift technology in networking. However, it is not practical to remove existing networks for building SDN networks or to replace all operating network devices with SDN-enabled devices. Therefore, SDN migration, which implies co-existing techniques and gradually moving to SDN, is an important issue. In this paper, we focus on how to integrate SDN networks with legacy networks which run Spanning Tree Protocol (STP). Our approach has three advantages. First, our approach does not require an SDN controller to apply the STP exchange APP on all switches but only on boundary switches. Second, our approach enables legacy networks to concurrently use multiple links that used to be blocked except one for avoiding loops. Third, our approach decreases BPDU frames used in STP construction and topology change.