Requirements for B-ISDN signalling - broadband services

The broadband ISDN (B-ISDN) is being tailored to become the universal (standardised)future network, and will be capable of supporting a wide range of multimedia, multi-party applications. It is based upon the same principles as its narrowband predecessor and hence can be regarded as a natural extension of narrow ISDN. However, the move away from constant bit rate circuit switching towards the use of asynchronous transfer mode (ATM) technology has provided much needed flexibility, especially in terms of the connection bandwidths and quality of service available to the user. This paper briefly describes the network capabilities that B-ISDN should support and how they have been derived from a representative sample of user applications principally proposed by ITU-T/ETSI and Digital Audio-Visual Council (DAVIC). The identification of the required network capabilities is the first step towards the specification of signalling protocols for the B-ISDN which must be flexible enough to support the envisaged wide range of current and future advanced applications and services. One such potential future B-ISDN application, which demonstrates the range of signalling functionality required is the 'Travel Agent Service' which is treated in detail.