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Routing and Wavelength Assignment for Wavelength-Routed WDM Networks

Routing and Wavelength Assignment for Wavelength-Routed WDM Networks. Combined routing and wavelength assignment problem Routing static: ILP formulation dynamic: on-line algorithms Wavelength assignment static: graph coloring approach dynamic: heuristics

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Routing and Wavelength Assignment for Wavelength-Routed WDM Networks

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  1. Routing and Wavelength Assignment for Wavelength-Routed WDM Networks • Combined routing and wavelength assignment problem • Routing • static: ILP formulation • dynamic: on-line algorithms • Wavelength assignment • static: graph coloring approach • dynamic: heuristics • A new wavelength assignment heuristic ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  2. RWA • Problem statement • Wavelength-continuity constraint ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  3. Combined Routing and Wavelength Assignment Problem ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  4. Routing - ILP Formulation ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  5. Routing - Algorithms For Dynamic Traffic • Fixed routing (On/Off line) • Fixed-alternate routing (On/Off line) • Adaptive routing (On line) • adaptive shortest path routing • least congested path routing ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  6. Wavelength Assignment with Known Lightpaths and Routes - Graph Coloring • Construct an auxiliary graph G(V,E) • Color the nodes of the graph G such that no two adjacent nodes have the same color • Sequential graph coloring approaches ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  7. Random First-Fit Least-Used/SPREAD Most-Used/PACK Min-Product Least Loaded MAX-SUM Relative Capacity Loss Wavelength Reservation Protecting Threshold Wavelength Assignment Heuristics ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  8. Illustrative Example wavelengths P1:(2,4) 3 2 1 0 0 1 2 3 4 5 6 Note: control network not shown. All wavelengths shown are for data traffic ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  9. Calculation of Max-Sum wavelengths P1:(2,4) 3 2 1 WPC: Wavelength-path Capacity 0 0 1 2 3 4 5 6 Wavelength selected: 0, 1, or 3 ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  10. Calculation of Relative Capacity Loss wavelengths P1:(2,4) 3 2 1 Wavelength selected: 1 or 3 0 0 1 2 3 4 5 6 ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  11. Simulation Network 2 1 2 1 1 0 3 1 1 1 1 5 4 2 Connection management protocol: link-state ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  12. Results from Others’ Publication 5x5 bidirectional mesh-torus, load/W = 25 Erlangs Source: S. Subramaniam and R. A. Barry, “Wavelength assignment in fixed routing WDM networks,” Proc. ICC'97 - International Conference on Communications, Montreal, Canada, vol. 1, pp. 406-410, June 1997. 20-node unidirectional ring, load/W = 1 Erlang R R FF, MU FF MS WC WC MU, MS # of wavelengths # of wavelengths (a) (b) ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  13. Computational Complexity • Wavelength reservation & Protecting threshold - constant • Random & First-Fit - O(W) • Min-Product & Least-Loaded - O(NW) • Least-Used & Most-Used - O(LW) • Max-Sum & Relative Capacity Loss - O(WN3) • where W - # of wavelengths, N - # of nodes, L - # of links ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  14. Wavelength selected: 3 * P1:(2,4) Distributed RCL Algorithm 3 2 1 0 0 1 2 3 4 5 6 RCL table at Node 2 ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  15. Characteristics of Distributed RCL • Less state information is exchanged • Faster computation of wavelength assignment upon a connection request • Can be combined with adaptive routing ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  16. Simulation Network 2 1 2 1 1 • Average propagation delay between two nodes: 0.107 ms • Average hop distance: 1.53 0 3 1 1 1 1 5 4 2 ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  17. Simulation Results of Distributed RCL Comparison of DRCL with adaptive routing and RCL with fixed routing ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  18. Conclusion for RWA L: # of links, N: # of nodes, W: # of wavelengths ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  19. Future Research • Survivable wavelength-routed WDM networks • previous work: static traffic & single link failure [S. Ramamurthy 1998] • higher layer protection -logical topology design with bundle cut in mind • WDM layer protection - dynamic traffic ECS 259 -- H. Zang and B. Mukherjee, UC Davis

  20. Future Research (Cont’d) • Managing multicast connections in wavelength-routed WDM networks • KMB • Bellman-Ford • Chain ECS 259 -- H. Zang and B. Mukherjee, UC Davis

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