SDNPS: A Load Balanced Topic Based Publish/Subscribe System in Software Defined Networking
Publish/subscribe systems on the traditional Internet suffer from poor scalability and high delay in the face of the Internet of Things (IoT) environment. Being customizable, the paradigm of software defined networking (SDN) provides a chance to establish an IoT specific network. In this paper, we propose an SDN based publish/subscribe system named SDNPS, which can construct and fine tune topic connected overlays for the sake of disseminating events efficiently and non redundantly based on a global topology overview. It organizes topics as a Huffman like topic tree and codes them into binary strings so that filtering and forwarding events can be operated directly on SDN configurable switches, which helps to reduce end to end latency. This hierarchical organization form of topic tree makes it possible to incrementally construct and store overlays, which contribute to reducing the time and space complexity of routing computation. More specifically, it achieves a better tradeoff between load balancing of the overall optimization objective and the minimal forwarding cost of per topic overlay.