Optical burst switched ring network with upstream prioritized switching and distributed fairness control

With a view to constructing a metropolitan network that can flexibly handle highly bursty traffic, an optical burst switched ring network with upstream prioritized switching and distributed fairness control is proposed. In optical burst switching, high burst drop rates at intermediate nodes constitute a problem. In the proposed system, burst signal dropping at the relay nodes is eliminated by means of upstream prioritized switching. At the same time, by using distributed fairness control, the problem of upstream prioritized switching-related unfairness, in which positional priority provides higher priority to more distant transmission nodes, is resolved. Further, by modifying the reservation of downstream nodes by using the trailer packet after disconnection of the transmission, unnecessary bandwidth is eliminated and the throughput is improved. By computer simulation, the throughput and the fairness with regard to the throughput are evaluated. It is shown that the proposed architecture exhibits excellent characteristics even in cases of hot-spot traffic, in which concentrated traffic occurs at a particular destination.