VIRTUAL TOPOLOGY RECONFIGURATION ISSUES IN EVOLUTION OF WDM OPTICAL NETWORKS

We consider the reconfiguration problem in multi-fiber WDM optical networks. In a real-time network as the traffic evolves with time: the virtual topology may not remain optimal for the evolving traffic, leading to a degradation of network performance. However, adapting the virtual topology to the changing traffic may lead to service disruption. This optimization problem hence captures the trade-off between network performance and number of reconfigurations applied to the virtual topology. The above problem is solved through a Mixed Integer Linear Programming formulation with a multivariate objective function, that captures both these parameters. However the problem is NP-hard and such an approach is unable to solve large problem instances in a reasonable time. In this paper, we also propose a simulated annealing based heuristic algorithm for solving problems of higher complexity. We compare the performance and the computation time of the MILP model and the heuristic algorithm considering different tests instances. Our results indicate that simulated annealing obtains results within 5% of the optimal solution, thus making it a viable approach in large scale networks.

[1]  Eytan Modiano,et al.  Dynamic load balancing in WDM packet networks with and without wavelength constraints , 2000, IEEE Journal on Selected Areas in Communications.

[2]  Biswanath Mukherjee,et al.  Virtual-topology adaptation for WDM mesh networks under dynamic traffic , 2003, TNET.

[3]  Rudra Dutta,et al.  Spare Capacity Provisioning for Dynamic Traffic Grooming in Optical Networks , 2006, 2006 3rd International Conference on Broadband Communications, Networks and Systems.

[4]  George N. Rouskas,et al.  A Survey of Virtual Topology Design Algorithms for Wavelength Routed Optical Networks , 1999 .

[5]  Byrav Ramamurthy,et al.  An analytical model for virtual topology reconfiguration in optical networks and a case study , 2002, Proceedings. Eleventh International Conference on Computer Communications and Networks.

[6]  Rudra Dutta,et al.  Research Problems in Dynamic Traffic Grooming in Optical Net works , 2004 .

[7]  Rajiv Ramaswami,et al.  Optical Networks , 1998 .

[8]  George N. Rouskas,et al.  Traffic adaptive WDM networks: a study of reconfiguration issues , 2001 .

[9]  Imrich Chlamtac,et al.  Lightpath communications: an approach to high bandwidth optical WAN's , 1992, IEEE Trans. Commun..

[10]  Biswanath Mukherjee,et al.  Dynamic traffic grooming in WDM mesh networks using a novel graph model , 2002, Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE.

[11]  Massimo Tornatore,et al.  WDM network optimization by ILP based on source formulation , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[12]  Kumar N. Sivarajan,et al.  Optical Networks: A Practical Perspective , 1998 .

[13]  Murti V. Salapaka,et al.  A practical approach to operating survivable WDM networks , 2002, IEEE J. Sel. Areas Commun..

[14]  Arun K. Somani,et al.  Request-specific routing in WDM grooming networks , 2002, 2002 IEEE International Conference on Communications. Conference Proceedings. ICC 2002 (Cat. No.02CH37333).