Optical tunnel allocation for WDM networks with multi-granularity switching capabilities

• Main Authors: Lee, S.S.W., Yuang, M.C., Po-Lung Tien, Lin, S.H.
• Format: Conference Proceeding
• Language: English
• Subjects: All-optical networks; Heuristic algorithms; Lagrangian functions; Optical devices; Optical fiber devices; Optical fiber networks; Optical switches; Wavelength assignment; Wavelength routing; WDM networks
• DOI: 10.1109/GLOCOM.2003.1258732

For WDM networks with multi-granularity switching, optical tunnel allocation (OTA) deals with the real-time establishment of optical tunnels between optical nodes through various optical multi-granularity switching devices. OTA is in principle a dynamic routing and wavelength assignment (RWA) problem with multi-granularity switching devices taken into account. In this paper, we propose a novel approximation approach, called Lagrangean relaxation with heuristics (LRH), aimed to resolve RWA considering both fiber and lambda switches. Such RWA is first formulated as a combinatorial optimization problem in which the bottleneck link utilization is to be minimized. To tackle the problem, the LRH approach performs constraint relaxation and derives a lower-bound solution index according to a set of Lagrangean multipliers generated through subgradient-based iterations. In parallel, using the generated Lagrangean multipliers, the LRH approach employs a new heuristic algorithm to arrive at a near-optimal upper-bound solution. Through numerical results and comparisons, we delineate that the LRH approach achieves a near-optimal solution, which is profoundly tight to its lower bound, at the expense of low computational time complexity.