Optical Packet Contention Resolution Through Edge Smoothing Into Decomposed Subflows

Motivated by the difficulty of implementing optical packet switches having large optical buffers, we propose a new, simple, and effective way of applying electronic traffic smoothing at the edge of an optical packet switched network to reduce core optical buffering requirements. A single class of service is assumed. Incoming traffic that is destined for a particular egress edge router is smoothed at each ingress edge router by a buffer scheduling algorithm and decomposed into several constant bit rate subflows, each with a uniform packet interarrival time. Each such subflow emerging from a core switch also retains these traffic characteristics. The rates of these subflows obey a simple mathematical relationship, and it is shown that, with the appropriate queuing strategy, this substantially reduces the core buffering requirements. Indeed, it is shown through analysis and simulation that scalability is improved over existing approaches, and computation is simplified. The proposal in this paper requires much less core buffering than one without smoothing, while compared with other smoothing proposals, it is more scalable both to large networks and a large number of smoothed flows. A condition on the fiber delay line buffer depth requirements is also derived for no packet loss to take place in any of the scenarios modeled in this paper. Furthermore, it is confirmed through simulation that packet jitter is not generated in the network core.