Figure 1 is an IPTV system structure model, this model has been practically applied in some domestic cities. In this model structure diagram, the entire IPTV system is divided into two parts: the back-end part and the user access part. The background part mainly provides media content management, user management, server management of the entire system, user authentication and billing management, and so on. The user access part provides users with video services and other services, and can be divided into multiple areas according to the size of the city. Each area mainly has a regional media base station and an EPG server. Users use set-top boxes [3] [4] [5] plus TV or PC as terminals to watch programs stored in the system or live TV programs through ADSL or cell broadband. The set-top box is a computer with simple functions, including hardware such as CPU, memory, network connection devices, decoders, and operating system and application software. It receives video signals transmitted through the broadband IP network, and the signals are processed and displayed on the TV. come out. The user uses the functions provided by the set-top box by manipulating the remote control.
Users are divided into multiple areas, each of which is deployed with multiple regional media servers and EPG servers. The user's video service and interactive interface are provided by the media servers and EPG servers in the user's area. This deployment method is easy to expand and suitable for large-scale deployment. Adding an area only requires the addition of regional media base stations and EPG servers, which will not affect the background and other areas. At the same time, most of the user's data traffic is concentrated in his own area, reducing the burden on the backbone network, and the breakdown of a single area system will not affect other areas.
The working process of the system is roughly as follows: ①The media source is processed by the media processing module into the format defined by the system, stored in the main media base station, and the media distribution management module in the background is responsible for how to distribute these programs to Media base station. ② At the same time, the information about the program is also sent to the EPG server for the EPG to display to the user. ③ The user logs on to the EPG server after starting the system after background authentication, and starts to browse the program information of the system. ④When the user selects a program to watch, EPG sends the program information and user information to the background section. The user management section of the background determines whether the user can enjoy the program. The request to play the program. ⑤ After the playback is completed, the set-top box sends a request to the background to deduct the corresponding charges, and at the same time, it is redirected to the EPG server, and the user can continue to browse and enjoy the program.
Considering that IPTV is still in the development stage in China, there are not many users in a region. At present, the system is designed to support up to 3000 users in one area, and the number of users accessing the EPG server at the same time does not exceed 500. When the number of users increases, you can use the EPG server cluster. In Figure 1, a master EPG server is deployed in each area. For the stability of the system, a standby EPG server is also deployed.
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