Pavilion: A Middleware Framework for Collaborative Web-Based Applications

This paper describes Pavilion, an object-oriented middleware framework for developing collaborative web-based applications. Pavilion enables a developer to construct new applications by inheriting and extending its default functionality. Reusable and extensible Pavilion components include interfaces to common web browsers, a reliable multicast protocol tailored for delivery of web resources, a leadership protocol for floor control, and a highly modular proxy server that supports data type-specific plug-ins. The architecture and operation of Pavilion are described, followed by a discussion of VGuide, a synchronous VRML application built using Pavilion. VGuide enables one user to lead other users through virtual worlds in a synchronous manner