The use of ISDN signaling for real-time applications at homes and small businesses

Integrated Services Digital Networks (ISDN) is an end-to-end digital telecommunications network providing the capability to transmit voice, data, facsimile, telemetry, signaling, and slow motion video. It provides a basic rate interface, 2B+D (2B for 2 bearer channels of 64 kbps each and D for delta channel of 16 kbps). It also provides primary rate interface 23B+D (1.544 Mbps equivalent to T1) in North America and 30B+D in Europe. In this paper we explore the use of narrowband ISDN for real-time applications in homes and small businesses. The paper concentrates on some real-time applications supported by the ISDN basic rate interface in homes and small businesses. In particular, ISDN LAP-D and call control protocols have been analyzed in detail, to support the real-time applications. High level scenarios, protocol message and bit level scenarios have been designed for the real-time applications.