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Author : Zhen Rong Zhang
Release : 2006
Genre : Wavelength division multiplexing
Kind : eBook
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Book Synopsis Design and Analysis of P-cycle-based Survivable Optical Networks by : Zhen Rong Zhang
Download or read book Design and Analysis of P-cycle-based Survivable Optical Networks written by Zhen Rong Zhang. This book was released on 2006. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Caroline Thennecy de Medeiros Rocha
Release : 2009
Genre :
Kind : eBook
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Book Synopsis Optimization of P-cycle Protection Schemes in Optical Networks by : Caroline Thennecy de Medeiros Rocha
Download or read book Optimization of P-cycle Protection Schemes in Optical Networks written by Caroline Thennecy de Medeiros Rocha. This book was released on 2009. Available in PDF, EPUB and Kindle. Book excerpt: Network survivability is a very interesting area of technical study and a critical concern in network design. As more and more data are carried over communication networks, a single outage can disrupt millions of users and result in millions of dollars of lost revenue. Survivability techniques involve providing some redundant capacity within the network and automatically rerouting traffic around the failure using this redundant capacity. This thesis concerns the design of survivable optical networks using p-cycle based schemes, more particularly, path-protecting p-cycles, in link failure scenarios. Our study focuses on the placement of p-cycle protection structures assuming that the working routes for the set of connection requests are defined a priori. Most existing work carried out on p-cycles concerns heuristic algorithms or methods suffering from critical lack of scalability. Thus, the objective of this thesis is twofold: on the one hand, to propose scalable models and solution methods enabling to approach larger problem instances and on the other hand, to produce optimal or near optimal solutions with mathematically proven optimality gaps. For this, we rely on the column generation technique which is suitable to solve large scale linear programming problems. Here, column generation is used as an intelligent way of implicitly enumerating promising cycles to be part of p-cycle designs. At first, we propose mathematical formulations for the master and the pricing problems as well as the first column generation algorithm for the design of survivable networks based on path-protecting p-cycles. The resulting algorithm obtains better solutions within reasonable running time in comparison with existing methods. Then, a much more compact formulation of the pricing problem is obtained. In addition, we also propose a new hierarchical decomposition method which greatly improves the efficiency of the whole algorithm and allows us to solve larger problem instances. As for integer solutions, two heuristic approaches are proposed to obtain good solutions. Next, we dedicate our attention to a systematic comparison of p-cycles and classical shared protection schemes. We perform an accurate comparison by using a unified column generation framework to find provably good results. Afterwards, our study concerns an empirical evaluation of directed and undirected link- and path-protecting p-cycles under asymmetric traffic scenarios. We show how much additional protection cost results from employing bidirectional systems in such scenarios. Finally, we investigate a column generation formulation for the design of p-cycle networks under availability requirements and obtain the first lower bounds for the problem.
Author :
Release : 2005
Genre :
Kind : eBook
Book Rating : /5 ( reviews)
Book Synopsis Optimization of P-cycle Protection Schemes in Optical Networks by :
Download or read book Optimization of P-cycle Protection Schemes in Optical Networks written by . This book was released on 2005. Available in PDF, EPUB and Kindle. Book excerpt: Network survivability is a very interesting area of technical study and a critical concern in network design. As more and more data are carried over communication networks, a single outage can disrupt millions of users and result in millions of dollars of lost revenue. Survivability techniques involve providing some redundant capacity within the network and automatically rerouting traffic around the failure using this redundant capacity. This thesis concerns the design of survivable optical networks using p-cycle based schemes, more particularly, path-protecting p-cycles, in link failure scenarios. Our study focuses on the placement of p-cycle protection structures assuming that the working routes for the set of connection requests are defined a priori. Most existing work carried out on p-cycles concerns heuristic algorithms or methods suffering from critical lack of scalability. Thus, the objective of this thesis is twofold: on the one hand, to propose scalable models and solution methods enabling to approach larger problem instances and on the other hand, to produce optimal or near optimal solutions with mathematically proven optimality gaps. For this, we rely on the column generation technique which is suitable to solve large scale linear programming problems. Here, column generation is used as an intelligent way of implicitly enumerating promising cycles to be part of p-cycle designs. At first, we propose mathematical formulations for the master and the pricing problems as well as the first column generation algorithm for the design of survivable networks based on path-protecting p-cycles. The resulting algorithm obtains better solutions within reasonable running time in comparison with existing methods. Then, a much more compact formulation of the pricing problem is obtained. In addition, we also propose a new hierarchical decomposition method which greatly improves the efficiency of the whole algorithm and allows us to solve larger problem instances. As for in.
Author : Canhui (Sam) Ou
Release : 2004
Genre :
Kind : eBook
Book Rating : /5 ( reviews)
Book Synopsis Design and Analysis of Survivable Optical Networks by : Canhui (Sam) Ou
Download or read book Design and Analysis of Survivable Optical Networks written by Canhui (Sam) Ou. This book was released on 2004. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Adrian Zymolka
Release : 2007-06-14
Genre : Mathematics
Kind : eBook
Book Rating : 531/5 ( reviews)
Book Synopsis Design of Survivable Optical Networks by Mathematical Optimization by : Adrian Zymolka
Download or read book Design of Survivable Optical Networks by Mathematical Optimization written by Adrian Zymolka. This book was released on 2007-06-14. Available in PDF, EPUB and Kindle. Book excerpt: The cost-efficient design of survivable optical telecommunication networks is the topic of this thesis. In cooperation with network operators, we have developed suitable concepts and mathematical optimization methods to solve this comprehensive planningtask in practice. Optical technology is more and more employed in modern telecommunication net-works.Digital information is therebytransmittedas short light pulses through glass fibers. Moreover, the optical medium allows for simultaneous transmissions on a single fiber by use of different wavelengths. Recent optical switches enable a direct forwarding of optical channels in the network nodes without the previously required signalretransformation to electronics. Their integration creates ongoingopticalconnections, which are called lightpaths. We study the problem of finding cost-efficient configurations of optical networks which meet specified communication requirements. A configuration comprises the determination of all lightpaths to establish as well as the detailed allocation of all required devices and systems. We use a flexible modeling framework for a realistic representation of the networks and their composition.For differentnetworkarchitectures, we formulate integer linear programs which model the design task in detail. Moreover, network survivability is an important issue due to the immense bandwidths offered by optical technology. Operators therefore request for designs which perpetuate protected connections and guarantee for a defined minimum throughput in case of malfunctions. In order to achieve an effective realization of scalable protection, we present a novel survivability concept tailored to optical networks and integrate several variants into the models. Our solution approach is based on a suitable model decomposition into two subtasks which separates two individually hard subproblems and enables this way to compute cost-efficient designs with approved quality guarantee. The first subtask consists of routing the connections with corresponding dimensioning of capacities and constitutes a common core task in the area of network planning. Sophisticated methods for such problems have already been developed and are deployed by appropriate integration. The second subtask is characteristic for optical networks and seeks for a conflict-free assignment of available wavelengths to the lightpaths using a minimum number of involved wavelength converters. For this coloring-like task, we derive particular models and study methods to estimate the number of unavoidable conversions. As constructive approach, we develop heuristics and an exact branch-and-price algorithm. Finally, we carry out an extensive computational study on realistic data, provided by our industrial partners. As twofold purpose, we demonstrate the potential of our approach for computing good solutions with quality guarantee, and we exemplify its flexibility for application to network design and analysis.
