Optical wavelength routing, translation, and packet/cell switched networks

We study several models for fixed-size packet/cell switching (e.g., 53 bytes for asynchronous transfer mode) in wavelength routed optical networks with an emphasis on throughput performance analysis. In particular, we examine the associated trade-offs between functionality and hardware complexity. The basic model here is a two-sided “switch” or sorter. Cells generated at user inputs destined for user outputs are allowed to reach their destinations by recirculation or multihop through a fixed wavelength routed optical network a number of times. Using algebraic techniques, we analyze the basic model and its variations that use different types of wavelength translation for their capability to achieve permutations of cells from inputs to outputs. In particular, we showed that when cell-by-cell wavelength translation functionality is allowed, the number of recirculations in the network to achieve all permutations is 3 log_W N where W is the number of wavelengths. The resultant normalized per user throughput of 1/3 log_W N is close to the conjectured optimal of 1/(2 log_W N-1) under the conditions specified in the model. Finally, using another model we show that it is possible to achieve a normalized per user throughput of 1 and we calculate the amount of extra hardware required for this purpose