The structure of the H. 323 protocol stack and the structure of the ip telephone system based on the H. 323 protocol explain the functions of the main equipment in the IP telephone network; then the RAS protocol, RADIUS protocol, and call signaling protocol are introduced.
H. 225.0 and media control protocol H. 245; finally introduced the non-fast call establishment process, fast call establishment process and call release process in the IP telephone network.
The H. 323 protocol was formulated by the ITU-T. The H. 323 standard includes the technical requirements for multimedia communication in a packet network without QoS guarantee. These packet networks include LAN, WAN, Internet, Internet, and networks that use packet protocols such as PPP to dial-up connections or point-to-point connections through PSTN or ISDN. The H. 323 system not only supports voice communication, but also supports a variety of video services (such as video conferencing) and data services (such as electronic whiteboard, file transmission) and so on. Although the H. 323 protocol is defined for multimedia communication, it is currently mainly used in ip telephone systems.
The applicable service of H.323 protocol is multimedia communication including voice, data and video and their combination. Among them, support for voice communication is a necessary function, and data and video communication are optional functions. H. 323 applies to the network is a packet-based network (PBN, Packet-Based Network), H. 323 assumes that PBN does not provide guaranteed quality of service QoS, that is, how to ensure the QoS of real-time communication requires additional network technology , This does not belong to the scope of the definition of H. 323. The technical content of H. 323 is mainly the system definition and general control process for multimedia communication on PBN. The H. 323 system requires the support of a set of protocols, including call control protocol, media control protocol, and audio and video coding protocols. These protocols specify detailed technical content and control procedures, and they are combined with H. 323 recommendations to form a packet network Technical standards for multimedia communications. The target system defined by H. 323 should be able to support the intercommunication between PBN and a variety of networks, including PSTN, ISDN, B-ISDN, and QoS-guaranteed LAN. Therefore, the gateway and its control are an important function considered by H. 323. The most important technical foundation of the ip telephone system is also the technical basis for the intercommunication of equipment from various manufacturers.
H. 225.0 and media control protocol H. 245; finally introduced the non-fast call establishment process, fast call establishment process and call release process in the IP telephone network.
The H. 323 protocol was formulated by the ITU-T. The H. 323 standard includes the technical requirements for multimedia communication in a packet network without QoS guarantee. These packet networks include LAN, WAN, Internet, Internet, and networks that use packet protocols such as PPP to dial-up connections or point-to-point connections through PSTN or ISDN. The H. 323 system not only supports voice communication, but also supports a variety of video services (such as video conferencing) and data services (such as electronic whiteboard, file transmission) and so on. Although the H. 323 protocol is defined for multimedia communication, it is currently mainly used in ip telephone systems.
The applicable service of H.323 protocol is multimedia communication including voice, data and video and their combination. Among them, support for voice communication is a necessary function, and data and video communication are optional functions. H. 323 applies to the network is a packet-based network (PBN, Packet-Based Network), H. 323 assumes that PBN does not provide guaranteed quality of service QoS, that is, how to ensure the QoS of real-time communication requires additional network technology , This does not belong to the scope of the definition of H. 323. The technical content of H. 323 is mainly the system definition and general control process for multimedia communication on PBN. The H. 323 system requires the support of a set of protocols, including call control protocol, media control protocol, and audio and video coding protocols. These protocols specify detailed technical content and control procedures, and they are combined with H. 323 recommendations to form a packet network Technical standards for multimedia communications. The target system defined by H. 323 should be able to support the intercommunication between PBN and a variety of networks, including PSTN, ISDN, B-ISDN, and QoS-guaranteed LAN. Therefore, the gateway and its control are an important function considered by H. 323. The most important technical foundation of the ip telephone system is also the technical basis for the intercommunication of equipment from various manufacturers.