Comparing with the un-slotted WDM (Wavelength Division Multiplexing) network, the slotted WDM network can establish more connections among the nodes at the same time. On the other hand, because of the head of slots, more slots in a frame will reduce the efficiency of optical channels. Based on the ring topology, the optimum slot number in slotted WDM networks is studied in this paper. For symmetrical traffic, the formulation of the slot number that supports the establishment of an all connection among the nodes in the network is brought out through mathematics. The result shows that a few wavelengths can support an all connection among the nodes. The number of wavelengths needed to set up connections for un-symmetrical traffic is discussed also.
Based on the ring topology and the applied technology at present, we propose an access and control protocol for optical packet switched metropolitan area DWDM (Dense Wavelength Division Multiplexing) network. In this paper, we have given an access and control protocol first, and explained the reservation of resource, the setting of optical transmitter and receiver, the control message, and then studied the properties of waiting delay through mathematic analysis and computer simulation.