Comparison of Floor Control Protocols for Collaborative Multimedia Environments

摘要

Improvements in networking allow for increasingly complex collaboration environments with regard to session scale, range of shared tasks, and distance between remote parties. Floor control protocols add an access discipline to such environments that allows one to mitigate race conditions on shared resources and throttle media transmission. Primary causes for resource competition among users may be the lack of mutual awareness and formal session orchestration, or network and host limitations. Various -- often proprietary and unscalable -- solutions for floor control have been implemented for telemedicine, video conferencing, and distributed interactive simulation. But to date, an analytic comparison of the efficacy of these solutions is lacking. Efficacy means the proportion of time that a protocol takes to allocate a resource, accounting for social and technical overhead from user behavior, protocol cost, and network conditions. The authors present a novel taxonomy and comparative performance analysis of known classes of floor control protocols, including socially driven protocols, collision sensing on shared resources, floor token passing in fully connected and ring topologies, and across shared control trees. Accordingly, aggregated and selective transmission of control information over a multicast control tree offers the best scalability and efficacy. A novel hierarchical floor control protocol correlating in its operation with tree-based reliable multicast is outlined.