CSA ISO/IEC 15056:02 (R2020)

CSA Preface Standards development within the Information Technology sector is harmonized with international standards development. Through the CSA Technical Committee on Information Technology (TCIT), Canadians serve as the Canadian Advisory Committee (CAC) on ISO/IEC Joint Technical Committee 1 on Information Technology (ISO/IEC JTC1) for the Standards Council of Canada (SCC), the ISO member body for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of the International Telecommunication Union (ITU), Canada participates in the International Telegraph and Telephone Consultative Committee (ITU-T). This International Standard was reviewed by the CSA TCIT under the jurisdiction of the Strategic Steering Committee on Information Technology and deemed acceptable for use in Canada. (A committee membership list is available on request from the CSA Project Manager.) From time to time, ISO/IEC may publish addenda, corrigenda, etc. The CSA TCIT will review these documents for approval and publication. For a listing, refer to the CSA Information Products catalogue or CSA Info Update or contact a CSA Sales representative. This Standard has been formally approved, without modification, by these Committees and has been approved as a National Standard of Canada by the Standards Council of Canada. Scope This International Standard specifies the signaling protocol for the support of the Transit Counter additional network feature (ANF-TC) at the Q reference point between Private Integrated Services Network Exchanges (PINXs) connected together within a Private Integrated Services Network (PISN). ANF-TC is a feature that limits the number of Transit PINXs that a call setup request may be routed through e.g., to protect the network against indefinite looping. The Q reference point is defined in ISO/IEC 11579- 1. Service specifications are produced in three stages and according to the method specified in CCITT Recommendation I. 130. This International Standard contains the stage 3 specification for the Q reference point and satisfies the requirements identified by the stage 1 and stage 2 specifications in ISO/IEC 15055. The signaling protocol for ANF-TC operates in association with the signaling protocols for basic circuit switched call control (as specified in ISO/IEC 11572) and call independent (connection oriented) signaling connections (as specified in ISOIIEC 11582). This International Standard also specifies additional signaling protocol requirements for the support of interactions at the Q reference point between ANF-TC and other supplementary services and ANFs. This International Standard is applicable to PINXs that can interconnect to form a PISN.