A role-based distributed publish/subscribe system in IoT
With the emerging of IoT (Internet of Things), the scale of Internet is extended extremely and large amounts of information are produced. Most previous work only focuses on the interconnection and interoperability problems among different entities and enterprise application systems in a dynamic interaction environment. However, the problems of how to efficiently disseminate the sensing information among the information providers and consumers on-demand still have not been comprehensively explored. In order to delivery various types of data in IoT on-demand, this paper proposed a role-based distributed publish/subscribe system (RBDS). RBDS is based on a hierarchy routing strategy of Grid. Firstly, the subscribers are mapped to appropriate role broker node by the organization of IoT data. Secondly, divide broker nodes into different groups based on role. In each group, broker nodes are separated into super nodes and common nodes according to their ability. Those super nodes are organized in upper Grid structure to distribute events in different groups. And the common nodes are organized in lower Grid structure to distribute events in the same group. It improves the scalability and decreases latency. At last, calculate the load of each broker node dynamically based on its capacity and its subscribers. Thereby the total number of subscribers on each broker node is efficiently balanced. Experimental results show that the RBDS can improve scalability, decrease latency and balance load effectively.