Broadband Integrated Services Digital Network (B-ISDN) and Broadband Private Integrated Services Network (B-PISN); Digital Subscriber Signalling System No.2 (DSS2)@ Broadband Inter-Exchange Signalling (B-QSIG)@ and Signalling System No.7 (SS7); Prenegotia
The present document specifies the signalling protocol for the purpose of prenegotiation at the QB@ SB@TB and co-incident SB/TB reference points within@ between and at the access to Broadband Private Integrated Services Networks and within@ between and at the access to public European Broadband Integrated Services Digital Networks. The protocol operates between two adjacent call control entities. The protocol is applicable in a separated call and bearer (connection) control environment for the support of calls having none@ one or multiple bearers. The protocol is applicable to a two-party call or a multi-party call. However@ prenegotiation is performed between two parties. In case of multi-party connections (point-to-multipoint connections)@ prenegotiation may be performed between the root and the first party. The QB reference point is defined in ISO/IEC 11579-1 [11]. The SB and TB reference points are defined in ITU-T Recommendation I.327 [12]. The present document is based on the transport capabilities as defined in ETS 300 796-1 [4] and ECMA-254 [1]@ and is closely related to the call control protocol specification as defined in EN 302 092-1 [5]. The purpose of prenegotiation as specified in the present document is to allow a user to check compatibility and availability at the remote user with regard to one or more connections the user intends to establish during the lifetime of the call@ without reserving connection-oriented resources in the network. Reservation of connection-oriented resources at the remote user is outside the scope of the present document.