Real-time lecture delivery connecting distant classrooms by redundant network combining a high-speed satellite (WINDS) and a terrestrial line (JGN2plus)

This paper reports on the authors' attempts for realtime lecture delivery between Japan, Thailand and Malaysia using a redundant network consisting of a high-speed internet satellite (WINDS) and a terrestrial line (JGN2plus). The feasibility of multi-site real-time distant lecture system has been confirmed in several lecture delivery experiments. Also, the robustness of system has been proved by near automatic switching of long-distance routes from satellite to ground and back. This enables to compensate for the weakness of the satellite link using the Ka band in case of heavy rainfall. Additionally, quality improvement of video and audio with a high definition teleconference system has been confirmed by questionnaire surveys.