ISO/IEC 21991:2002 信息技术-系统间通信和信息交换-全体通信网络-QSIG和H.323之间网络信号 完成呼叫辅助服务

标准编号：ISO/IEC 21991:2002

中文名称：信息技术-系统间通信和信息交换-全体通信网络-QSIG和H.323之间网络信号 完成呼叫辅助服务

英文名称：Information technology — Telecommunications and information exchange between systems — Corporate Telecommunication Networks — Signalling interworking between QSIG and H.323 — Call completion supplemen

发布日期：2002-06

标准范围

ISO/IEC 21991:2002规定了“QSIG”和“H.323”之间的信令互通，以支持公司电信网络(CN)内的呼叫完成补充服务。“QSIG”是在专用综合业务网络(PISN)内的专用综合业务网络交换机(PINX)之间的Q参考点处操作的信令协议。Q参考点在ISO/IEC 11579-1中定义。PISN向其用户提供电路交换基本服务和补充服务。QSIG在其他标准中有规定，特别是ISO/IEC 11572(支持基本服务的呼叫控制)、ISO/IEC 11582(支持补充服务的通用功能协议)和许多规定个别补充服务的标准。ISO/IEC 13870规定了支持呼叫完成服务的QSIG协议。“H.323”是一组信令协议，用于支持分组网络内的语音或多媒体通信，特别是使用互联网协议(IP)作为其网络层协议(IP网络)的分组网络。H.323信令协议在IP网络中的端点之间操作，或者经由一个或多个网守间接地操作，或者直接地操作。端点可以是终端或到另一个网络的网关。H.323是指各种ITU-T建议的“总括”建议，特别是建议H.225.0和H.245（基本通信能力）和建议H.450.1（用于支持补充服务的通用功能协议）。建议H.450.9规定了支持呼叫完成服务的H.323协议。323(也称为H.323版本2)和更高版本。在ISO/IEC 13870(QSIG)和ITU建议H.450.9(H.323)中，呼叫完成补充服务是对忙用户的呼叫完成(SS-CCB)和无应答呼叫完成(SS-CCNR)。QSIG和H.323之间的互通允许在PISN的用户处发起的呼叫终止于专用IP网络的用户处，或者在专用IP网络的用户处发起的呼叫终止于PISN的用户处。在这种情况下，ISO/IEC 21991:2002允许当被叫用户在忙（SS-采用QSIG的PISN和采用H.323的公共IP网络之间的互通超出了ISO/IEC 21991:2002的范围。然而，ISO/IEC 21991:2002中规定的功能在与其他相关功能(例如，号码转换、安全功能等)结合部署时原则上适用于这种情况。ISO/IEC 21991:2002适用于可以充当采用QSIG的PISN和采用H.323的专用IP网络之间的网关的任何互通单元。

ISO/IEC 21991:2002 specifies signalling interworking between "QSIG" and "H.323" in support of call completion supplementary services within a Corporate telecommunication Network (CN).

"QSIG" is a signalling protocol that operates at the Q reference point between Private Integrated services Network eXchanges (PINX) within a Private Integrated Services Network (PISN). The Q reference point is defined in ISO/IEC 11579-1. A PISN provides circuit-switched basic services and supplementary services to its users. QSIG is specified in other Standards, in particular ISO/IEC 11572 (call control in support of basic services), ISO/IEC 11582 (generic functional protocol for the support of supplementary services) and a number of standards specifying individual supplementary services. ISO/IEC 13870 specifies the QSIG protocol in support of call completion services.

"H.323" is a set of signalling protocols for the support of voice or multimedia communication within a packet network, in particular a packet network that uses the Internet Protocol (IP) as its network layer protocol (IP network). H.323 signalling protocols operate between endpoints in an IP network, either indirectly via one or more gatekeepers, or directly. An endpoint can be a terminal or a gateway to another network. H.323 is an "umbrella" recommendation referring to various ITU-T recommendations, in particular Recommendations H.225.0 and H.245 (basic communication capabilities) and Recommendation H.450.1 (generic functional protocol for the support of supplementary services). Recommendation H.450.9 specifies the H.323 protocol in support of call completion services.

NOTE H.450.9 applies only to the 1998 version of H.323 (also known as H.323 version 2) and to later versions.

In both ISO/IEC 13870 (QSIG) and ITU-Recommendation H.450.9 (H.323), the call completion supplementary services are Completion of Calls to Busy Subscribers (SS-CCBS) and Completion of Calls on No Reply (SS-CCNR). These supplementary services apply after a call establishment attempt has failed because the called user was busy or not available, and provide means to re-establish the call when the called user becomes available.

Interworking between QSIG and H.323 permits a call originating at a user of a PISN to terminate at a user of a private IP network, or a call originating at a user of a private IP network to terminate at a user of a PISN. In such a scenario, ISO/IEC 21991:2002 allows the completion of calls when the called user becomes available after having been busy (SS-CCBS), or having not answered the original call (SS-CCNR).

Interworking between a PISN employing QSIG and a public IP network employing H.323 is outside the scope of ISO/IEC 21991:2002. However, the functionality specified in ISO/IEC 21991:2002 is in principle applicable to such a scenario when deployed in conjunction with other relevant functionality (e.g., number translation, security functions, etc.).

ISO/IEC 21991:2002 is applicable to any interworking unit that can act as a gateway between a PISN employing QSIG and a private IP network employing H.323.

标准预览图