Realtime Communication Middleware Based On Rtps

Communication is basic of real-time application just like SCADA system. Data is meaningful only when it is transferred reliably in a limited time. Distributed real-time application has unique communication requirements. Real-time applications must handle different kinds of data flow;many nodes intercommunication making data flow complex;and dynamic configuration changes occur as nodes leave and join the network. Strict timing requirements further complicate the entire design. Traditional client-server architectures route all communications through a central server. This makes them ill-suited to handle real-time data distribution. Publish subscribe architectures,designed to distribute data to many nodes simultaneously and anonymously,have clear advantages for real-time application developers. In publish subscribe model,publisher and subscriber send or receive data anonymously and does not need to have detail information of networks,nor address of other nodes. Application can be publisher or subscriber or both of them. Publish subscribe work well in distributed application which handles complex data flow. Publish subscribe,as an effective communication model in real-time application,becomes popular more and more. We may say that publish subscribe model is success both in theory and application,its development is meaningful to whole communication system. This essay,together with the feather of SCADA system,examines the principle and model of publish subscribe,describes the architectural advantages and limitations of it,and introduces a network middleware that implements publish subscribe in the way of ActiveX components. At last we compare our design with other products abroad and make further prediction.