Middleware for Scalable Real-time Multimedia Cyberinfrastructure

Abstract

Middleware is a layer of software that is used by applications to locate people and resources and to provide security. Middleware in the form of authentication, authorization, and directory services is especially of interest for improving the scalability and security of managed multimedia applications. This paper describes the problems, challenges and solutions to creating middleware for real-time voice/videoconferencing applications. As part of the Internet2 Middleware and National Science Foundation Middleware Initiatives, we have designed, built and deployed middleware for scalable videoconferencing and other Internet multimedia applications. Two standards are currently used for signaling in such applications: H.323, the ITU-T signaling standard used in most of today’s commercial video-conferencing systems; and Session Initiation Protocol (SIP), an IETF approved standard for voice and video communications. Specific outcomes of our research include the creation of the International ITU-T standard called H.350 Directory Services Architecture for Multimedia Conferencing; an advanced SIP-based videoconferencing client that is secure and H.350 enabled; a prototype H.323 endpoint that is H.350 enabled; a Video Middleware ‘Cookbook’ that fully documents the H.350 architecture and provides detailed examples for software developers as well as configuration and deployment instructions; a large-scale test bed; example local and global directory services; and an architecture supporting single-sign-on authentication that is consistent with the federated administration model.