A novel and simple beforehand bandwidth reservation (BBR) MAC protocol for OBS metro ring networks

Abstract

This paper proposes a novel and simple MAC protocol called beforehand bandwidth reservation (BBR) to reserve the empty slots in the next big-slot cycle for OBS ring networks by control channel. The node architecture uses one tunable transmitter and one fixed receiver to add or drop data channels and a fixed transmitter/receiver pair to transmit and receive on the control channel. Each node possesses a dedicated channel to receive data, so it inherently occupies a priority position. Fortunately, a well-known packet scheduling approach, time-division multiplexing (TDM), can overcome this problem. In addition, the length of the big-slot cycle is studied with a view to investigating performance divergence. Finally, a multi-token protocol using the (FT^W–FR^W) node architecture is compared with the BBR protocol. According to simulation results, the BBR scheme using the TDM approach achieves the best bandwidth utilization (more than 95%), while the multi-token protocol achieves the worst performance based on packet distribution in the MCI backbone.