Wavelength Defragmentation for Seamless Migration

Jaumard, Brigitte; Pouya, Hamed; Coudert, David

doi:10.1109/jlt.2019.2924914

Cited by 3 publications

(2 citation statements)

References 33 publications

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“…Network resource fragmentation is incurred by dynamic traffic and reduces network efficiency [1]. As part of the resource reallocation by rerouting, many studies have looked at optical path (lightpath) rerouting, both in the context of routing and wavelength allocation (RWA) [2] and routing and spectrum allocation (RSA) [3], or IP / VPN rerouting to overcome failures. However, very few authors have studied rerouting at the IP layer (or Layer 3) for the sole purpose of overcoming fragmentation, optimizing the network resources and increasing the throughput.…”

Section: Introductionmentioning

confidence: 99%

Minimum Disturbance Rerouting to Optimize Bandwidth Usage

Duong

Jaumard

Coudert

2021

2021 International Conference on Optical Network Design and Modeling (ONDM)

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Dynamic traffic leads to bandwidth fragmentation, which drastically reduces network performance, resulting in increased blocking rate and reduced bandwidth usage. When rerouting traffic flows at Layer 3 of an optical network, network operators are interested in minimizing the disturbances in order to satisfy their Service Level Agreements. Therefore, they turn to the Make-Before-Break (MBB) paradigm.In this paper, we revisit MBB rerouting with the objective of identifying the reroute sequence planning that minimizes the number of reroutes in order to minimize the resource usage. We propose a Dantzig-Wolfe decomposition mathematical model to solve this complex rerouting problem. We instigate how multiple or parallel rerouting reduces the overall minimum number of rerouting events (shortest makespan), and achieve the best resource usage. Numerical results bring interesting insights on that question and show a computational time reduction by about one order of magnitude over the state of the art.

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Section: Introductionmentioning

confidence: 99%

Minimum Disturbance Rerouting to Optimize Bandwidth Usage

Duong

Jaumard

Coudert

2021

2021 International Conference on Optical Network Design and Modeling (ONDM)

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“…After it is identified that a network is highly fragmented, a network defragmentation event is triggered. The state of the art in network defragmentation is to recover the stranded bandwidth by minimizing resource requirements modeled as a deterministic minRWA problem (Jaumard et al 2019). It obtains a set of lightpaths assigned to the granted connections on the network (target provisioning).…”

Section: Introductionmentioning

confidence: 99%

Stochastic RWA and Lightpath Rerouting in WDM Networks

Daryalal¹,

Bodur²

2020

Preprint

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In a telecommunication network, Routing and Wavelength Assignment (RWA) is the problem of finding lightpaths for incoming connection requests. When facing a dynamic traffic, greedy assignment of lightpaths to incoming requests based on predefined deterministic policies leads to a fragmented network that cannot make use of its full capacity due to stranded bandwidth. At this point service providers try to recover the capacity via a defragmentation process. We study this setting from two perspectives: (i) while granting the connection requests via the RWA problem and (ii) during the defragmentation process by lightpath rerouting. For both problems, we present the first two-stage stochastic integer programming model incorporating incoming request uncertainty to maximize the expected grade of service. We develop a decomposition-based solution approach, which uses various relaxations of the problem and a newly developed problem-specific cut family. Simulation of two-stage policies for a variety of instances in a rolling-horizon framework of 52 stages shows that our stochastic models provide high-quality solutions compared to traditionally used deterministic ones. Specifically, the proposed provisioning policies yield improvements of up to 19% in overall grade of service and 20% in spectrum saving, while the stochastic lightpath rerouting policies grant up to 36% more requests using up to just 4% more bandwidth spectrum.

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Stochastic RWA and Lightpath Rerouting in WDM Networks

Daryalal

Bodur

2022

INFORMS Journal on Computing

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In a telecommunication network, routing and wavelength assignment (RWA) is the problem of finding lightpaths for incoming connection requests. When facing a dynamic traffic, greedy assignment of lightpaths to incoming requests based on predefined deterministic policies leads to a fragmented network that cannot make use of its full capacity because of stranded bandwidth. At this point, service providers try to recover the capacity via a defragmentation process. We study this setting from two perspectives: (i) while granting the connection requests via the RWA problem and (ii) during the defragmentation process by lightpath rerouting. For both problems, we present the first two-stage stochastic integer programming model incorporating incoming request uncertainty to maximize the expected grade of service. We develop a decomposition-based solution approach, which uses various relaxations of the problem and a newly developed problem-specific cut family. Simulation of two-stage policies for a variety of instances in a rolling-horizon framework of 52 stages shows that our stochastic models provide high-quality solutions when compared with traditionally used deterministic ones. Specifically, the proposed provisioning policies yield improvements of up to 19% in overall grade of service and 20% in spectrum saving, while the stochastic lightpath rerouting policies grant up to 36% more requests, using up to just 4% more bandwidth spectrum. Summary of Contribution: For handling the intrinsic uncertainty of demand in the telecommunications industry, this paper proposes novel stochastic models and solution methodology for two fundamental problems in telecommunications at operational level: (i) routing and wavelength assignment (RWA) and (ii) lightpath rerouting problem. Despite the vast literature on the RWA problem, stochastic optimization has not been considered as a viable solution for resource allocation in optical networks. We propose two-stage stochastic programming models for both problems and design efficient decomposition-based solution methods that use various relaxations of the models and a new family of cutting planes. Our extensive and rigorous numerical experiments show the significant merit of incorporating uncertainty into decision making, as well as the effectiveness of the decomposition framework and our newly designed family of cuts in enhancing the solvability of both models. This work opens new avenues to explore where the powerful stochastic programming literature can be leveraged to make operational decisions in telecommunications problems, a field that currently relies mostly on deterministic and heuristic solution methods.

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Wavelength Defragmentation for Seamless Migration

Cited by 3 publications

References 33 publications

Minimum Disturbance Rerouting to Optimize Bandwidth Usage

Minimum Disturbance Rerouting to Optimize Bandwidth Usage

Stochastic RWA and Lightpath Rerouting in WDM Networks

Stochastic RWA and Lightpath Rerouting in WDM Networks

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