CitiTime: a system for rapid creation of portable next-generation telephony services

We present the architecture, design and experimental research prototype implementation of CitiTime, an open system architecture for the rapid development of advanced next-generation telephony services that overcomes some of the limitations of the current closed PSTN architecture and service model. CitiTime allows communication sessions to be set up over the PSTN, the Internet, or a combination of both. Services can be provided by multiple cooperating distributed service providers, some of whom may use third-party software components which can be ``plugged in'' or even dynamically downloaded from the network as needed. This allows advanced services to be deployed and delivered to users rapidly, a crucial requirement in the increasingly competitive telecommunications services marketplace. CitiTime is built upon an object-oriented call model called citi call control (CCC) which we have de®ned as a small set of extensions to the standard Java telephony API (JTAPI) call model. JTAPI is designed primarily for centralized, single provider, call center type applications. Our extensions provide support for multiple, distributed providers as well as advanced services. CCC hides details of underlying call-state management, protocols and hardware from applications. The CitiTime prototype software is currently operational in our laboratory. We brie ̄y describe its current implementation as well as future work to address issues such as fault tolerance. Ó 2000 Elsevier Science B.V. All rights