MigrateSDN: efficient approach to integrate OpenFlow networks with STP-enabled networks

Software defined networking (SDN) is a paradigm-shifting technology in networking. However, in current network infrastructures, removing existing networks to build pure SDN networks or replacing all operating network devices with SDN-enabled devices is impractical because of time and cost involved in the process. Therefore, SDN migration, which implies the use of co-existing techniques and a gradual move to SDN, is an important issue. In this paper, we focus on how SDN networks can be integrated with legacy networks that use spanning tree protocol (STP). Our approach demonstrates three advantages. First, our approach does not require an SDN controller to apply the STP exchange 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 bridge protocol data unit (BPDU) frames used in STP construction and topology change.