In this article, we mainly introduce a standardized networking design idea that integrates the ONVIF and GB/T28181-2011 standards.
Network Structure Model
For a typical rail transit networking architecture, we can be divided into three levels.
Station level: Stand-alone system for station monitoring. The control server performs local display, video recording, and peripheral device access. The control server is also responsible for providing call service for local resources to the line operation center.
Line layer: The network monitoring system at the level of the urban rail line manages the call of the video resources of all stations on the line, handles the alarm information of the station, and also provides services for requesting video calls outside the line.
Networking layer: A virtualized networking data exchange system that provides image information to the upper-level operation center or city-level image monitoring system or other command system of the urban rail system.
The role of the system
Station front-end video equipment: deployed in the station monitoring subsystem, outputs digital video signals, and performs video compression coding, and the compressed code stream is transmitted through the network.
Station video decoder: deployed in station control rooms, police stations and other places, call the front-end video equipment stream, decoding output to the monitor.
Station control server: In response to a station control terminal request, an instruction is issued to control the decoder to call the front-end video.
Respond to control commands from the operations center and forward the front-end video stream to the central decoder.
Access the alarm equipment around the station and generate the corresponding linkage.
Station control terminal: Issue a call instruction.
The OCC control gateway of the operation center responds to the client's instruction and sends a command for calling the station video to the station control server by using the standard control protocol; in response to the control protocol of the upper gateway, calls the video to the station control server and forwards it to the upper layer gateway.
Operations Center OCC Client: Instructs to call station video.
Operation Center OCC decoder/big screen display control: decodes and displays the station video stream forwarded by the station control server.
External Control Gateway: Respond to the client's instructions and use the standard control protocol to send an instruction to the OCC control gateway to call the station video; and forward the corresponding video.
Overall standard system design
In the range below the station, ONVIF can be used as a standardized framework for device access and management. Above the station, GB/T28181-2011 is used as the main communication protocol for networking. The main reasons are:
First of all, the area within the station is a centralized area for equipment, and a large number of equipment interfaces are also within the station area. Adopting the ONVIF standard that equipment manufacturers support better and more mature, the feasibility is better, and the equipment selection area is wider.
Secondly, adopting GB/T28181-2011 at the level above the line and externally shared system interfaces can guarantee future access to the *, government emergency command, intelligent transportation and other large platforms, with certain forward-looking.
Finally, if we use H.264 on the codec standard and carefully select both the ONVIF and GB/T28181 transmission and packaging requirements, the audio and video streams can be basically translated from the front-end to the back-end, ensuring the system. The integrity.
Network Structure Model
For a typical rail transit networking architecture, we can be divided into three levels.
Station level: Stand-alone system for station monitoring. The control server performs local display, video recording, and peripheral device access. The control server is also responsible for providing call service for local resources to the line operation center.
Line layer: The network monitoring system at the level of the urban rail line manages the call of the video resources of all stations on the line, handles the alarm information of the station, and also provides services for requesting video calls outside the line.
Networking layer: A virtualized networking data exchange system that provides image information to the upper-level operation center or city-level image monitoring system or other command system of the urban rail system.
The role of the system
Station front-end video equipment: deployed in the station monitoring subsystem, outputs digital video signals, and performs video compression coding, and the compressed code stream is transmitted through the network.
Station video decoder: deployed in station control rooms, police stations and other places, call the front-end video equipment stream, decoding output to the monitor.
Station control server: In response to a station control terminal request, an instruction is issued to control the decoder to call the front-end video.
Respond to control commands from the operations center and forward the front-end video stream to the central decoder.
Access the alarm equipment around the station and generate the corresponding linkage.
Station control terminal: Issue a call instruction.
The OCC control gateway of the operation center responds to the client's instruction and sends a command for calling the station video to the station control server by using the standard control protocol; in response to the control protocol of the upper gateway, calls the video to the station control server and forwards it to the upper layer gateway.
Operations Center OCC Client: Instructs to call station video.
Operation Center OCC decoder/big screen display control: decodes and displays the station video stream forwarded by the station control server.
External Control Gateway: Respond to the client's instructions and use the standard control protocol to send an instruction to the OCC control gateway to call the station video; and forward the corresponding video.
Overall standard system design
In the range below the station, ONVIF can be used as a standardized framework for device access and management. Above the station, GB/T28181-2011 is used as the main communication protocol for networking. The main reasons are:
First of all, the area within the station is a centralized area for equipment, and a large number of equipment interfaces are also within the station area. Adopting the ONVIF standard that equipment manufacturers support better and more mature, the feasibility is better, and the equipment selection area is wider.
Secondly, adopting GB/T28181-2011 at the level above the line and externally shared system interfaces can guarantee future access to the *, government emergency command, intelligent transportation and other large platforms, with certain forward-looking.
Finally, if we use H.264 on the codec standard and carefully select both the ONVIF and GB/T28181 transmission and packaging requirements, the audio and video streams can be basically translated from the front-end to the back-end, ensuring the system. The integrity.
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