Abstract
This work addresses the grooming, routing and wavelength assignment with regeneration (GRWAR) problem for meshed networks in static traffic scenarios. It focuses primarily on the grooming and routing with regeneration (GRR) problem. Physical impairments were considered in the model, imposing a limit in lightpath lengths without regeneration. This creates the opportunity to strategically place transponders for both grooming and regeneration. The GRR problem is tackled lexicographically, which means that for a given network topology and a traffic matrix, the goal is to route and groom connection requests in a way that minimizes the number of transponders and, for that number of transponders, throughout minimum length routes. To solve this problem, an integer linear programming (ILP) formulation was developed considering undirected networks and explicitly including the relationship between the different network layers. The results of the ILP model are used to validate a heuristic suited to be included in a software-defined network (SDN) platform in a multilayer core network. The GRWAR problem is addressed after a solution for the GRR problem is obtained, using a first-fit approach to assign wavelengths to the lightpaths obtained by the ILP and the heuristic. The wavelength assignment problem is less critical due to the large number of wavelengths per fiber. The ILP and the heuristic were compared for small networks, with the heuristic providing good results in very short time, proving to be efficient and better suited for larger problems, as is confirmed through a set of proposed bounds.
Highlights
The problem of routing, assigning wavelengths and network resources to traffic demands is well known as the Routing and Wavelength Assignment (RWA) problem [1]
The problems of traffic grooming and regenerator placement are handled sequentially, there are a few works that explore the combination of both [4], [7], [8]. These works address the problem of impairment-aware traffic grooming in Wavelength Division Multiplexing (WDM) networks, where the aim is to route traffic and lightpaths and to place regenerators and electronic grooming equipment in a way that minimizes the network cost
The results of the heuristic are validated by means of bounds, as explained in Subsection IV-A. This problem results from the evaluation of a novel strategy to manage, via an integrated Software Defined Network (SDN) platform, a multilayer core network constituted by a meshed optical network transporting traffic (of Multiprotocol Label Switching (MPLS) type, for instance)
Summary
The problem of routing, assigning wavelengths and network resources to traffic demands (without traffic grooming) is well known as the Routing and Wavelength Assignment (RWA) problem [1]. The problems of traffic grooming and regenerator placement are handled sequentially, there are a few works that explore the combination of both [4], [7], [8] These works address the problem of impairment-aware traffic grooming in Wavelength Division Multiplexing (WDM) networks, where the aim is to route traffic and lightpaths and to place regenerators and electronic grooming equipment in a way that minimizes the network cost. Patel et al [4] address the problem of traffic grooming and regenerator placement in a WDM optical network considering hop-constrained lightpaths due to physical impairments. A ILP formulation is proposed for routing the demands and considering a cost-effective data aggregation by muxponders All formulations address both unprotected and protected (1+1) traffic.
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