มาตรฐานของโปรโตคอล H.323
โพสต์แล้ว: 22 ธ.ค. 2009 17:36
บทความต่อไปนี้นำมาจาก http://en.wikipedia.org/wiki/H.323
H.323 is an umbrella Recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences.[1]
It is widely implemented by voice and videoconferencing equipment manufacturers, is used within various Internet real-time applications such as GnuGK and NetMeeting and is widely deployed worldwide by service providers and enterprises for both voice and video services over Internet Protocol (IP) networks.
It is a part of the ITU-T H.32x series of protocols, which also address multimedia communications over Integrated Services Digital Network (ISDN), Public Switched Telephone Network (PSTN) or Signaling System 7 (SS7), and 3G mobile networks.
H.323 Call Signaling is based on the ITU-T Recommendation Q.931 protocol and is suited for transmitting calls across networks using a mixture of IP, PSTN, ISDN, and QSIG over ISDN. A call model, similar to the ISDN call model, eases the introduction of IP telephony into existing networks of ISDN-based PBX systems, including transitions to IP-based Private Branch eXchanges (PBXs).
Within the context of H.323, an IP-based PBX might be an H.323 Gatekeeper or other call control element that provides service to telephones or videophones. Such a device may provide or facilitate both basic services and supplementary services, such as call transfer, park, pick-up, and hold.
While H.323 excels at providing basic telephony functionality and interoperability, H.323’s strength lies in multimedia communication functionality designed specifically for IP networks.
Contents
1 History
2 Protocols
3 Codecs
4 H.323 Architecture
4.1 H.323 Network Elements
4.1.1 Terminals
4.1.2 Multipoint Control Units
4.1.3 Gateways
4.1.4 Gatekeepers
4.1.5 Border Elements and Peer Elements
4.2 H.323 Network Signaling
4.2.1 H.225.0 Call Signaling
4.2.2 RAS Signaling
4.2.3 H.245 Call Control
4.2.3.1 Capability Negotiation
4.2.3.2 Master/Slave Determination
4.2.3.3 Logical Channel Signaling
4.2.3.4 Fast Connect
5 Use cases
5.1 H.323 and Voice over IP services
5.2 H.323 and Videoconference services
5.3 International Conferences
6 Alternatives
7 See also
8 ITU-T Recommendations of the H.323 System
9 External links
9.1 General
9.2 Papers
9.3 Projects
H.323 is an umbrella Recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences.[1]
It is widely implemented by voice and videoconferencing equipment manufacturers, is used within various Internet real-time applications such as GnuGK and NetMeeting and is widely deployed worldwide by service providers and enterprises for both voice and video services over Internet Protocol (IP) networks.
It is a part of the ITU-T H.32x series of protocols, which also address multimedia communications over Integrated Services Digital Network (ISDN), Public Switched Telephone Network (PSTN) or Signaling System 7 (SS7), and 3G mobile networks.
H.323 Call Signaling is based on the ITU-T Recommendation Q.931 protocol and is suited for transmitting calls across networks using a mixture of IP, PSTN, ISDN, and QSIG over ISDN. A call model, similar to the ISDN call model, eases the introduction of IP telephony into existing networks of ISDN-based PBX systems, including transitions to IP-based Private Branch eXchanges (PBXs).
Within the context of H.323, an IP-based PBX might be an H.323 Gatekeeper or other call control element that provides service to telephones or videophones. Such a device may provide or facilitate both basic services and supplementary services, such as call transfer, park, pick-up, and hold.
While H.323 excels at providing basic telephony functionality and interoperability, H.323’s strength lies in multimedia communication functionality designed specifically for IP networks.
Contents
1 History
2 Protocols
3 Codecs
4 H.323 Architecture
4.1 H.323 Network Elements
4.1.1 Terminals
4.1.2 Multipoint Control Units
4.1.3 Gateways
4.1.4 Gatekeepers
4.1.5 Border Elements and Peer Elements
4.2 H.323 Network Signaling
4.2.1 H.225.0 Call Signaling
4.2.2 RAS Signaling
4.2.3 H.245 Call Control
4.2.3.1 Capability Negotiation
4.2.3.2 Master/Slave Determination
4.2.3.3 Logical Channel Signaling
4.2.3.4 Fast Connect
5 Use cases
5.1 H.323 and Voice over IP services
5.2 H.323 and Videoconference services
5.3 International Conferences
6 Alternatives
7 See also
8 ITU-T Recommendations of the H.323 System
9 External links
9.1 General
9.2 Papers
9.3 Projects