The Design And Implementation Of The Server Side Of A Monitoring System Based On IMS Standard

Developed from analog data to digital data, from local surveillance to remote surveillance based on networks, monitoring system has got great progress in technology and stability. However, as the requirements developing and the business expanding, there are some shortcomings blocks the development of monitoring system, such as terminals' location, access manner, monitoring mode, system deployment, etc. The 3GPP R5 proposed a subsystem—IMS (IP Multimedia Subsystem), which can be used to support services across wireline and wireless access networks. It can solve the problems mentioned above to design a monitoring system based on IMS standards.On the basis of SIP, RTP/RTCP, the author proposes a monitoring system based on IMS standards. It is divided into three layers: the media layer, the session control layer, and the application layer. The application layer is used to realize monitoring function, and to control the business; the session control layer is used to initiates, to modify, or to terminate the media session; the media layer is used to transport media stream. But as the complexity of the entities in IMS, the author makes some simplification job for the entities and for the interactions between them. Then, the author proposes the top level design of the monitoring system. Functionally, the system includes the application server, the monitoring terminals, and the observe terminals. The application server supports the video images, the history record management interface, and the business control interface. The monitoring terminals can be located almost everywhere, it is used to collect media, encode media and transport them. The observe terminals can also be located everywhere; it is used to support video images for common users.The modules in the application server in the monitoring system based on IMS standards are: the GUI module, the terminal management module, the signaling module, the stream handler module, the player module, the decoder module, and the history record management module. The main control module, terminal management module and the history record management module are used for business control; the signaling module is used for session control; the stream handler module is used for media transport; the player module and the decoder module are used to decode media stream and draw video images. The terminal management module and the stream handler module are realized based on the singleton design mode and the windows message mechanism; and the module reusability and extensibility are also concerned.So far, the most requirements of the application server side in monitoring system based on IMS standards are realized, such as the monitoring function, the history record management function, etc. But some aspects are still need to be perfected, such as dialog-in session modifying, observe terminal management and error handling, etc.