Optical Tunnel Allocation for WDM Networks with Multi-granularity Switching Capabilities

Steven S W Lee, Maria C. Yuang, Po-Lung Tien, S. H. Lin

Research output: Contribution to conferencePaperpeer-review


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.

Original languageEnglish
Number of pages5
StatePublished - 1 Dec 2003
EventIEEE Global Telecommunications Conference GLOBECOM'03 - San Francisco, CA, United States
Duration: 1 Dec 20035 Dec 2003


ConferenceIEEE Global Telecommunications Conference GLOBECOM'03
Country/TerritoryUnited States
CitySan Francisco, CA


  • Combinatorial optimization problem
  • Lagrangean relaxation
  • Multi-granularity switching capabilities
  • Optical tunnel allocation
  • Routing and Wavelength Assignment (RWA)
  • Subgradient method
  • Wavelength Division Multiplexing (WDM)


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