A novel online wavelength assignment algorithm in wavelength-convertible multi-granular optical networks

Abstract

As industrial technology gets more mature, a single fiber can offer more and more wavelengths. However, it also results in a large amount of switching ports at optical cross-connects (OXCs). Certainly, it is expected that higher and higher complexity is inevitable to control and manage such large OXCs. In this paper, we study the dynamic wavelength assignment problem in waveband switching (WBS) networks composed of multi-granular OXCs (MG-OXCs). Moreover, in order to relax the wavelength continuity constraint on lightpath establishments, each MG-OXC node is equipped with a certain number of converters. To efficiently minimize the extra port consumption and utilize wavelength converters, we proposed an online wavelength assignment algorithm named Least Weighted Configuration Cost (LWCC). For a new request, LWCC first adopts fixed routing and then exploits the layered-graph approach and a new cost function for edge weight assignment to determine adequate wavelength(s). The performance metrics of interest include both blocking performance and converter utilization. Numerical results show that LWCC is superior in waveband grouping and therefore results in significant performance gain in terms of blocking probability.

Performance analysis of an optical network employing waveband and traffic grooming

“…The differences between single and three-layer MG-OXC architectures and their features are well described in references [5][6][7]. The restriction related to the use of single-layer MG-OXCs represents a resource limitation, which was adopted in our paper in order to highlight the effect of the waveband technique on the network performance.…”

“…Typically, a MG-OXC is formed by a switching fabric, which commutes traffic in fiber (FXC), wavelength (WXC), and waveband (BXC), as well as by optical multiplexers and demultiplexers at the BXC and WXC layers, which allow add and drop operations at specific wavebands and/or wavelengths. The features of several MG-OXC architectures as well the optimal solutions of the waveband switching (WBS) problem have been discussed in several papers [2][3][4][5][6][7][8][9]. Aspects of interest include the minimization of the number of used ports and the proposition of efficient algorithms for routing and waveband/wavelength assignment.…”