A totally ordered and secure multicast protocol for distributed virtual environment

Sharing a virtual space with many users, a distributed virtual reality environment (DVE) provides high level communication and cooperative design facilities. For a large-scale DVE in a wide area network, a reliable and efficient multicast protocol on the Internet is necessary. We have developed a reliable multicast protocol based on the sequence server and evaluated it using simulation. From the simulation result, our protocol is more scalable than RMP (reliable multicast protocol). However, the protocol has an obvious drawback in that the ordering cost is centralized to the sequence server. Therefore, the scalability and extensibility is limited. Furthermore, security support is not provided. It is an important factor for reality of the DVE system. We propose a method to distribute the workload to some servers to make the protocol scalable and extensile. From our simulation result, the message arrival time to members is drastically reduced. We also propose a key distribution mechanism for secure multicast communication