Collaborative virtual environments (CVE) require the use of specially designed mechanisms that allow for a consistent sharing of state among involved users. These mechanisms must, somehow, compensate for network latency and losses in such a way that all players have a single, coherent perception of the system state. Common middleware platforms have difficulty in guaranteeing this consistency, and this is the prime reason why the main research topic for CVEs is the efficient, scalable and reliable transmission of state information. This paper presents a state transmission framework developed for a middleware platform that was constructed by the authors in an earlier project [1]. This middleware platform, Augmented Reliable Multicast CORBA Event Service (ARMS), which already supported several QoS adaptation mechanisms and reliable transmission in multicast environments, was extended with CVE-oriented state transmission mechanisms. After an identification of key requirements of collaborative virtual environments, the relevant features of the proposed state transmission framework are presented. This framework has been integrated in the ARMS platform and was subject to a series of performance tests whose results are included and discussed in this paper. The paper ends with a summary of contributions and an identification of guidelines for further work.
展开▼
