CollabKit - A Multi-User Multicast Collaboration System based on VNC

Diplomarbeit aus dem Jahr 2011 im Fachbereich Informatik - Angewandte Informatik, Humboldt-Universität zu Berlin, Sprache: Deutsch, Abstract: Computer-supported real-time collaboration systems offer functionality to let two or more users work together at the same time, allowing them to jointly create, modify and exchange electronic documents, use applications, and share information location-independently and in real-time. For these reasons, such collaboration systems are often used in professional and academic contexts by teams of knowledge workers located in different places. But also when used as computer-supported learning environments - electronic classrooms - these systems prove useful by offering interactive multi-media teaching possibilities and allowing for location-independent collaborative learning. Commonly, computer-supported real-time collaboration systems are realised using remote desktop technology or are implemented as web applications. However, none of the examined existing commercial and academic solutions were found to support concurrent multi-user interaction in an application-independent manner. When used in low-throughput shared-medium computer networks such as WLANs or cellular networks, most of the investigated systems furthermore do not scale well with an increasing number of users, making them unsuitable for multi-user collaboration of a high number of participants in such environments. For these reasons this work focuses on the design of a collaboration system that supports concurrent multi-user interaction with standard desktop applications and is able to serve a high number of users on low-throughput shared-medium computer networks by making use of multicast data transmission. The developed multi-user multicast collaboration system named CollabKit, realised by integrating and extending existing technologies, was compared against a conventional unicast remote desktop system and found to significantly outperform it when several clients needed to be served. Regarding the functionality requirements and performance metrics defined in this work, CollabKit could achieve the expected results. This work shows that it is possible to create a computer-supported real-time collaboration system with multi-user and multicast support by integrating existing technologies and extending them with custom implementations where needed: The developed system supports application-independent concurrent operation by multiple users, per-user graphical annotations and window sharing and scales well with an increasing number of users.