ISO IEC 21410:2001 pdf download - Information technology — Telecommunications and information exchange between systems — Corporate telecommunication networks — Signalling interworking between QSIG and H.323 — Call transfer supplementary services

ISO IEC 21410:2001 pdf download – Information technology — Telecommunications and information exchange between systems — Corporate telecommunication networks — Signalling interworking between QSIG and H.323 — Call transfer supplementary services

ISO IEC 21410:2001 pdf download – Information technology — Telecommunications and information exchange between systems — Corporate telecommunication networks — Signalling interworking between QSIG and H.323 — Call transfer supplementary services.
1 Scope This International Standard specifies signalling interworking between “QSIG” and “H.323” in support of the call transfer supplementary services within a Corporate telecommunication Network (CN). “QSIG” is a signalling protocol that operates at the Q reference point between Private Integrated Services 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 13869 specifies the QSIG protocol in support of call transfer by consultation and ISO/IEC 19460 specifies the QSIG protocol in support of single step call transfer. “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.450.2 specifies the H.323 protocol in support ofcall transfer. NOTE – H.450.2 applies only to the 1998 version ofH.323 (also known as H.323 version 2) and to later versions. Call transfer by consultation, as supported by ISO/IEC 13869, is a supplementary service that enables a user (user A) to transform two ofthat user’s calls (at least one ofwhich must be answered) into a new call between the two other users in the two calls (users B and C). Single step call transfer, as supported by ISO/IEC 19460, is a supplementary service that enables a user (user A) to transform an existing call between user A and user B into a new call between user B and user C without user A needing to establish a call with user C prior to transfer. Call transfer, as supported by H.450.2, is a supplementary service that enables the served user (user A) to transform an existing call with a second user (user B) into a new call between user B and a third user (user C) selected by user A. User A may or may not have a call established with user C prior to call transfer. If a call is already established between user A and user C, this is known as transfer by consultation and is equivalent to call transfer as supported by ISO/IEC 13869. If a call is not already established between user A and user C, this is known as single step call transfer and is equivalent to call transfer as supported by ISO/IEC 19460.