Optimization And Implementation Of Route Module Of SDN-Based Pub/Sub Information Midware

In the Internet of Thing, data flow is in real time and large scale.Therefore, it requires system to be more efficient and reliable. This requirement certainly brings challenges to distributed information middleware. Luckily, the core idea of Software Defined Network (SDN)perfectly fits this requirement. SDN aims at separating controlling layer and data layer of network devices. With this idea, SDN-Based Pub/Sub Information Middleware is able to acquire OpenFlow switches' status, and then down flows into these switches using RESTful APIs of group controller.Thanks to others' previous research over Pub/Sub system in the traditional network and new features provided by SDN, this paper introduces a new approach to optimize the efficiency of the route calculation module of SDN-Based Pub/Sub Information Middleware. New route calculation module is redesigned using algorithm based on Steiner Tree. New features like distributed route calculation and flow generation are now added into new route calculation module.The new approach also adds some new features to topology module and subscription module. With new controller, OpenDaylight, topology module is able to sense and construct physical topology of local group. In order to obtain the global network, we implement Hello process to build and maintain the global network topology. As for subscription module,with uniting and splitting subscription table, messages can be forwarded in a higher speed with better accuracy. The 2-level flow-table design also helps accelerate data transmission.The route calculation module has a better calculation efficiency compared with the old one. The distributed calculation approach also makes this process more stable and reliable. In the last part of our work,we establish a multi-group experiment environment based on OpenvSwitch and KVM to check the functions and efficiency of the modules that we optimize. The results prove our work to be worthwhile.