implementation and empirical evaluations of floor control protocols on planetlab network
Nowadays users from different parts of the world participate in collaborative applications (online games, video-conferencing, distributed large-scale simulations) over the Internet. These applications require that at any point in time only one user can exclusively access a shared resource. The problem of providing exclusive access to shared resources in collaborative applications is known as the floor control problem. Centralized and distributed protocols for floor control problem have been proposed in the literature and simulation experiments have been conducted to study the performance of these protocols. None of these protocols have been tested on the real Internet. In this paper, we present empirical evaluations of different floor control protocols on PlanetLab network which is an overlay testbed that connects several academic institutions and industrial research labs all over the world in a virtual network. We have implemented two flavors of distributed solutions -- the randomized Aloha and the scheduled DQDB (Distributed Queue Dual Bus) based protocols. We have also implemented the centralized protocol where the users send floor requests to a central node and the central node schedules the floor requests based on First in First Out. The protocols are implemented using Berkeley Software Distribution (BSD) sockets API. For the experiments, nodes from different PlanetLab sites are selected to resemble that users from different parts of the world are participating in a collaborative application. Average waiting time to gain a floor is used as the performance metric.
floor control protocol performance evaluation