International Journal of
Information and Education Technology

Abstract

Peer-to-Peer computing technology brings satisfactory distance education to a large number of people at anytime anywhere with a low cost. While many online learning systems connect students asynchronously or provide them with recorded lectures, few systems focus on facilitating synchronous collaborative work among learners. Low latency requirement, dynamic group members and limited out-degree of nodes pose great challenge on P2P solutions to virtual interactive learning environments. Most application level multicast protocols are heuristic algorithms of minimum spanning tree, aiming to reach the optimal parameters like latency concerning all nodes. However, few studies are focusing on providing stringent low perceived latency based on specific features of audio group communication. In this paper, we propose a gossip-enhanced multicast protocol called GellCast for online language learning to provide “natural” group discussions in problem solving. We then present an online collaborative language learning system called PPCOEC, a distributed Virtual interactive Oral English Classroom, which is powered by GellCast. Making realistic presumptions on processing delay at each node, GellCast guarantees stringent low latency among discussion participants while providing relatively low latency among listeners. Hence, it provides satisfying low perceived latency to all users. Simulation results show the feasibility and efficiency of the approach.