Scalable WDM network architecture based on photonic slot routing and switched delay lines

Photonic slot routing (PSR) is a promising approach to solving the fundamental scalability problem of all-optical packet switched WDM networks. In this approach adjacent subnetworks can exchange wavelength sensitive traffic through bridges using wavelength non-selective devices which can be constructed using proven technologies. With photonic slot routing, packets sharing a common subnetwork destination are aggregated to form a photonic slot which is individually routed in order to reach the destination subnetwork. Photonic slots from different subnetworks can originate contentions at the bridge, leading to potential penalties of slot loss and retransmission. This paper shows how slot contention penalties can be reduced through the use of switched delay lines (SDL) at the bridges. The combination of these two innovative techniques, the photonic slot routing and the switched delay lines, leads to a unique solution that is shown to nearly achieve throughput and delay performance obtainable in absence of slot contentions.