Research On Management And Performance Of BACnet Internet

BACnet is the most competitive standard in building automation system control field. As an open and interoperating standard, BACnet was released in Jun, 1995, and used extensively in building automation control field. BACnet developed from an institute standard to an international standard. The applying range of BACnet has been developed from Building automation control system field to smart home, fire protection, city surveillance even industry control field. However, with the expanding of applying field, scale of BACnet network becomes more and more large. However, management and quality of service (QoS) of BACnet network lags behind. So BACnet's network management, especially performance management is of importance to establish large scale BACnet network and realize its QoS. Combining the study of building automation system and smart home, the thesis studies the management and QoS of BACnet network.The thesis puts forward the concept of BACnet internet to describe the extended BACnet network. According to the network management and QoS demand of BACnet internet, the thesis gives the management model of networked control system based on BACnet internet (BACnet NCS). Through math analysis of BACnet NCS'model, the thesis gives the united state model of NCS based on BACnet internet and sets up the mapping relationship of quality of control (QoC) and network QoS. At the same time, objective and content of BACnet NCS'management is given. To enhance the QoS of BACnet internet, congestion control, traffic control and task management of BACnet internet have been studied. The thesis studies the following concept:(1) Function model, control method, system management and network management of BACnet internet are summarized and induced.(2) Puts forward the idea to establish BACnet internet by using IP technology to interlink native BACnet network and non-native BACnet network. Control streaming, data streaming and multimedia streaming can be integrated together by IP technology. The realization of BACnet broadcast management device and BACnet router is given, which can be used to establish BACnet internet.(3) Puts forward the united state model of BACnet NCS. From control theory and concept network aspect, the model's analysis has been described. The mapping realization of the control loop's QoC and QoS of BACnet NCS is discussed. For every control loop's QoC, BACnet internet must ensure its QoS demands. Further more, good QoS of BACnet internet is achieved by right network management method. (4) Infection factor of BACnet internet's QoS has been analyzed. Analysis result indicates that time delay in BACnet internet is the main network induced time delay infection factor. The thesis puts forward that enhance the BACnet inernet's QoS by decreasing the queuing time delay through congestion control. According to BACnet internet's feature, enhanced random early detection (ERED) algorithm has been given to realize BACnet internet's congestion control. Combining active queue management (AQM), priority management and explicit cogestion notification (ECN), the algorithm ensures the QoS demand of BACnet internet. Needn't to change BACnet network's structure, ERED algorithm provides better QoS for control loop.(5) Puts forward heterogeneity streaming concept and BACnet internet's middleware to control BACnet internet's access of multitask. Middleware of BACnet internet provides very well mechanism and method for accessing of multitask in BACnet internet. Based on BACnet protocol stack software, traffic control of BACnet smart home is realized. Test result has been given. The idea can combine with rate based RED (RPRED) algorithm, makes use of BACnet internet and realizes multi-information sharing and offers better QoS.(6) BACnet internet's task management model has been given. The thesis models the BACnet internet's tasks as whole task and local task. BACnet internet's scheduling model has been given. Put forward enhanced earliest deadline first (EDF) algorithm for whole task and enhanced rate-monotonic (RM) algorithm for local task in BACnet internet. Corresponding schedulability condition has been given. Experiment tests the configuration, auto configuring and scheduling of BACnet internet's task. Test result shows that the task model and its scheduling algorithm are suitable for BACnet internet's task management.