Fast Wavelength Reservation Method for Distributed Lightpath Setup in WDM Networks

Abstract A promising approach to the effective utilization of wavelength division multiplexed networks is to transfer the data on an on-demand basis using fast wavelength reservation. The data can then be transferred using the assigned wavelength channel. However, if wavelength reservation fails, the lightpath setup delay, which is de-fined as the time from when the data–transfer request arises at the source node to when the lightpath between the source–destination pair is successfully established, is seriously affected since retrials of the wavelength reservation are in turn delayed by propagation delays. In this paper, we propose a new wavelength reservation method to reduce the lightpath setup delay. The computer simulation results show that our method can setup the lightpath faster than the conventional method. Furthermore, to evaluate our proposal more clearly, we limit the number of retrials and evaluate the blocking probability that lightpath cannot be established. From the computer simulation, our proposal shows better blocking probability regardless of the number of retrials. Key words WDM network, lightpath, lightpath setup delay, blocking probability, retrial — 1 — 1