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New cooperative mechanisms for software defined networks based on hybrid switches

Software defined networking (SDN) aims to provide simplified network design, operation, and management using a decoupled control plane. However, its centralized control and global network knowledge present scalability and reliability issues, which makes SDN deployment very challenging. In this paper, we propose and evaluate a hybrid switch with partial delegation of basic bridging and new cooperative mechanisms between controller and switches. This delegation offloads the SDN controllers while maintaining the capability to install forwarding rules on the switches. In this way, we take full advantage of hybrid switches in addition to using them as backwards compatible equipment, which interoperates with traditional switches.We validate this proposal by implementing a hybrid OpenFlow switch on an open source software switch as a proof of concept. Scalability and path setup delay are improved with respect to traditional centralized SDN solutions, because of the reduction in controller load and, in turn, because of the reduced traffic between switches and controller. Our cooperative mechanisms focus on recovering failures, obtaining the best performance of all approaches on higher loads, and providing a good trade‐off between controller based and traditional distributed approaches.