Ip Multicast-based Collaborative Learning Systems And Technology Research

Synchronous Collaborative Learning (SCL) is an important research task that combines Tele-education with Computer-Supported Collaborative Learning (CSCL). In this thesis, we studies not only the process and features of SCL using IP multicast technology, but also some key technologies hi these fields.1. We propose an architecture for collaborative learning using IP multicast technology, which aims to realize a web-based collaborative learning environment, hi this thesis, the architecture of SCL based on IP multicast is divided into three components: Audio/Video IP multicast environment which has the function of self-adaptive congestion control; IP multicast environment based on web-based synchronous browsing; and management on multiple SCL sessions.2. After studying self-adaptive IP multicast technology, especially congestion control technology, we propose a self-adaptive congestion control method, in which multicast traffic is handled in a TCP-Friendly mode.3. we propose to replace screen copy and T.120 conference with web-based synchronous browsing mode in SCL. The latter refers to using web browser as the user interface and taking web pages as the data environment of synchronous lectures. And synchronization events are transmitted in a reliable IP multicast, which is based on the Scalable Reliable Real Transport Protocol [6]( SRRTP).4. After careful studying of SAP/SDP protocol, we design an incompact multicast session management model, which is based on announcement and sense of multicast.5. Based on all the ideas proposed in this paper, a SCL system, WebLearning Plus, is developed. It has been running on the NUDT campus network and verifying our conclusions.