ECS H. Zang and B. Mukherjee, UC Davis 1 Routing and Wavelength Assignment for Wavelength-Routed WDM Networks Combined routing and wavelength assignment problem Routing u static: ILP formulation u dynamic: on-line algorithms Wavelength assignment u static: graph coloring approach u dynamic: heuristics A new wavelength assignment heuristic
ECS H. Zang and B. Mukherjee, UC Davis 2 RWA Problem statement Wavelength-continuity constraint
ECS H. Zang and B. Mukherjee, UC Davis 3 Combined Routing and Wavelength Assignment Problem
ECS H. Zang and B. Mukherjee, UC Davis 4 Routing - ILP Formulation
ECS 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) u adaptive shortest path routing u least congested path routing
ECS 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 H. Zang and B. Mukherjee, UC Davis 7 Wavelength Assignment Heuristics Random First-Fit Least-Used/SPREAD Most-Used/PACK Min-Product Least Loaded MAX-SUM Relative Capacity Loss Wavelength Reservation Protecting Threshold
ECS H. Zang and B. Mukherjee, UC Davis 8 Illustrative Example wavelengthsP 1 :(2,4) Note: control network not shown. All wavelengths shown are for data traffic
ECS H. Zang and B. Mukherjee, UC Davis 9 Calculation of Max-Sum Wavelength selected: 0, 1, or 3 WPC: Wavelength-path Capacity wavelengthsP 1 :(2,4)
ECS H. Zang and B. Mukherjee, UC Davis 10 Calculation of Relative Capacity Loss Wavelength selected: 1 or wavelengthsP 1 :(2,4)
ECS H. Zang and B. Mukherjee, UC Davis 11 Simulation Network Connection management protocol: link-state
ECS H. Zang and B. Mukherjee, UC Davis 12 Results from Others’ Publication 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 , June (a)(b) R R MS MU, MS WC FF, MU WC FF 20-node unidirectional ring, load/W = 1 Erlang # of wavelengths 5x5 bidirectional mesh-torus, load/W = 25 Erlangs
ECS 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(WN 3 ) where W - # of wavelengths, N - # of nodes, L - # of links
ECS H. Zang and B. Mukherjee, UC Davis 14 Distributed RCL Algorithm P 1 :(2,4) RCL table at Node 2 * Wavelength selected: 3
ECS 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 H. Zang and B. Mukherjee, UC Davis 16 Simulation Network Average propagation delay between two nodes: ms Average hop distance:
ECS 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 H. Zang and B. Mukherjee, UC Davis 18 Conclusion for RWA L: # of links, N: # of nodes, W: # of wavelengths
ECS H. Zang and B. Mukherjee, UC Davis 19 Future Research Survivable wavelength-routed WDM networks u previous work: static traffic & single link failure [S. Ramamurthy 1998] u higher layer protection -logical topology design with bundle cut in mind u WDM layer protection - dynamic traffic
ECS H. Zang and B. Mukherjee, UC Davis 20 Future Research (Cont’d) Managing multicast connections in wavelength-routed WDM networks u KMB u Bellman-Ford u Chain