All-optical WDM multi-rings with differentiated QoS

This article considers all-optical WDM networks based on a slotted multicha nnel ring topology, where nodes are equipped with one fixed-wavelength rece iver and one wavelength-tunable transmitter, and shows how to design very e ffective MAC protocols that provide packet-mode transport to multiple infor mation flows with different QoS requirements. As an example, we describe SR 3, a collision-free slotted MAC protocol which combines a packet scheduling strategy (called SRR), a fairness control algorithm (called MMR), and a re servation mechanism. SRR achieves an efficient exploitation of the availabl e bandwidth, MMR guarantees fair throughput access to each node, and SR3, b y permitting slot reservations. leads to tighter control on access delays, and can thus effectively support traffic classes with different QoS require ments.