WDM networks planning under multi-hour traffic demand with the MatPlanWDM tool

Periodic reconfiguration of the virtual topology in transparent optical networks has been recently investigated as a mechanism to more efficiently adapt the network to predictable periodic traffic variations along the day or week. The scheduling of periodic reconfigurations should consider the trade-off between a lower network cost obtained through better resource allocation, and the undesired traffic disruptions that these reconfigurations may cause. This paper presents and compares two algorithms for planning virtual topology reconfiguration suitable for exploring this trade-off. The first is based on a Lagrangian relaxation of the planning problem, and the second is based on a Tabu Search Tabu Search meta-heuristic. The merits of both algorithms are compared. Keywords: virtual topology design, network planning, multi-hour traffic, Lagrangian relaxation, Tabu search. I TRODUCTIOTransparent optical networks based on Wavelength Division Multiplexing (WDM) have become an accepted solution for new broadband backbone networks [1]. In these networks, traffic is carried through transparent alloptical connections, called lightpaths. A lightpath is established between an optical transmitter in the originating node and an optical receiver in the terminating node over a wavelength channel in each traversed fibre. Since the traffic carried over a lightpath is wavelength switched at intermediate nodes, the costs associated to the data electronic processing are saved. The set of lightpaths established onto a physical topology to support a given set of traffic demands (in Gbps) is called a virtual topology. The Virtual Topology Design (VTD) problem implies solving a two-layered routing problem: in the upper layer, it involves routing traffic flows (demands) over the virtual topology; while in the lower layer, it involves finding a Routing and Wavelength Assignment (RWA) [2] of lightpaths over the physical topology. In this work, we assume network scenarios with an over-provisioned fiber plant where a feasible RWA solution exists for almost any lightpath in the virtual topology, focusing only on the upper layer routing problem.The VTD problem under multi-hour or periodic traffic is denoted as Multi-Hour Virtual Topology Design (MH-VTD) [3]. In this case, the set of traffic demands are represented as a temporal sequence of traffic matrices, reflecting traffic variations over a period of time (e.g. a day or a week). The MH-VTD problem can be classified into: (i) the MH-VTD-NR (non-reconfigurable) problem, where a time-fixed (non-reconfigurable) virtual topology is planned to carry the traffic demand at any time; (ii) the MH-VTD-R (reconfigurable) problem where a time-varying (reconfigurable) virtual topology is designed to more efficiently adapt to known (or estimated) traffic variations. In both problems classes, we consider the number of optical transceivers in the network as the measure of the network cost to optimize. The present work is focused on the MH-VTD-R problem where, as a second optimization criterion, the ...

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WDM networks planning under multi-hour traffic demand with the MatPlanWDM tool

Cited by 2 publications

References 12 publications

Software Tools and Methods for Research and Education in Optical Networks

Software Tools and Methods for Research and Education in Optical Networks

Algorithms for virtual topology reconfiguration under multi-hour traffic using Lagrangian relaxation and Tabu search approaches

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