Collaborative design using distributed virtual reality over the Internet

Efficient collaborative virtual environments are missing. First, current solutions do not support mobility to move easily from a disconnected work to a meeting. Second, they do not preserve the consistency or they limit the parallel working. Third, a client-server approach is inefficient in many ways. It introduces a bottleneck and a point of failure in the system. At last, requiring a specific Quality of Service (QoS) from the under-laying network limits the ease of deployment. Paper answers these shortages. It enables to distribute a global scene tree among several private spaces. A worker carries out a disconnected work to improve his private space while satisfying protection rules. These different puzzle pieces assemble automatically into a global scene tree during a meeting work. Workers modify in real-time the shared scene. Real time awareness, parallel working and work persistency are provided. A consistency property guaranties the work progression. The solution is fully distributed. Full replication and multicasting improve the performances. A connection facility solves the connectivity problem. It switches automatically from multicast to point-to-point. At last, security is addressed. Standard and secure email enables authentication and distribution of a session key. A re-keying protocol assures confidentiality without requiring communication entities to process X509 certificates.