A FRAMEWORK FOR THE DEVELOPMENT OF TOLERANT REAL-TIME APPLICATIONS

This work presents a framework architecture for the development of dis tributed real-time applications to be integrated into WWW clients. It assumes a WWW environment over networks providing a best-effort delive ry service like the internets based on the IP protocol. The framework is that of an application programming interface (API) providing the pr ogram developer with the services needed by tolerant real-time applica tions. Once developed, an application is bundled together with the API to form a WWW plug-in which can subsequently be called from a WWW cli ent interface or browser. The application is then perceived as being i ntegrated into the WWW environment. The design aims to provide real-ti me applications with a transport service layer assuring near end-to-en d isochronism despite the weak guaranties of the underlying network se rvice. The implementation of the mechanisms that allow multistream rea l-time communications to adapt to the operational conditions of these networks are discussed. In this work, the RTP and RTCP protocols were also implemented as part of the API. Experience with this framework re ports the development of a prototype real-time application for multime dia group communication and the analysis of the behaviour of RTP sessi ons in a real operational situation. The analysis uses protocol state data logged during their operation. (C) 1998 Elsevier Science B.V. All rights reserved.