A bandwidth guaranteed multi-access protocol for WDM local networks

In this paper, we propose a bandwidth guaranteed multi-access protocol for broadcast-and-select WDM local networks with a star topology. The proposed protocol is based on a combination of contention and reservation mechanisms for time slotted WDM networks. Every node accesses the data channel by transmitting request packets in minislots on a separate control channel. There are two types of minislots; reservation minislots and contention minislots. Nodes repairing bandwidth guarantees, called guaranteed nodes, use reservation minislots that are assigned by the control node. The remaining nodes share contention minislots using a random access mechanism. Each node dynamically assigns data channels for the minislots successfully returned on a first-come-first-served (FCFS) basis. Then, the number of reservation minislots is allocated by the control node. The remaining minislots are used for contention minislots. The reservation minislots can guarantee a minimum bandwidth for the guaranteed nodes. The contention minislots enable on-demand services at the optical layer and achieve good fairness for the remaining bandwidth. This protocol can be implemented with a simple distributed algorithm that efficiently utilizes the data channel.