TY - CHAP A1 - Orlowski, Sebastian A1 - Koster, Arie M.C.A. A1 - Raack, Christian A1 - Wessäly, Roland T1 - Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics T2 - Proceedings of the INOC 2007, Spa, Belgium, also ZIB Report ZR-06-47 Y1 - 2007 UR - http://www.zib.de/Publications/abstracts/ZR-06-47 PB - International Network Optimization Conference CY - Spa, Belgium ER - TY - GEN A1 - Orlowski, Sebastian A1 - Pioro, Michal A1 - Tomaszewski, Artur A1 - Wessäly, Roland T1 - SNDlib 1.0--Survivable Network Design Library N2 - We provide information on the Survivable Network Design Library (SNDlib), a data library for fixed telecommunication network design that can be accessed at http://sndlib.zib.de. In version 1.0, the library contains data related to 22 networks which, combined with a set of selected planning parameters, leads to 830 network planning problem instances. In this paper, we provide a mathematical model for each planning problem considered in the library and describe the data concepts of the SNDlib. Furthermore, we provide statistical information and details about the origin of the data sets. T3 - ZIB-Report - 07-15 KW - telecommunication network design KW - data library KW - optimization Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9582 ER - TY - GEN A1 - Koster, Arie M.C.A. A1 - Orlowski, Sebastian A1 - Raack, Christian A1 - Bayer, Georg A1 - Engel, Thomas T1 - Single-layer Cuts for Multi-layer Network Design Problems N2 - We study a planning problem arising in SDH/WDM multi-layer telecommunication network design. The goal is to find a minimum cost installation of link and node hardware of both network layers such that traffic demands can be realized via grooming and a survivable routing. We present a mixed-integer programming formulation that takes many practical side constraints into account, including node hardware, several bitrates, and survivability against single physical node or link failures. This model is solved using a branch-and-cut approach with problem-specific preprocessing and cutting planes based on either of the two layers. On several realistic two-layer planning scenarios, we show that these cutting planes are still useful in the multi-layer context, helping to increase the dual bound and to reduce the optimality gaps. T3 - ZIB-Report - 07-21 KW - telecommunication network KW - multi-layer network design KW - mixed-integer programming KW - cutting planes Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9641 SN - 1438-0064 ER - TY - CHAP A1 - Koster, Arie M.C.A. A1 - Orlowski, Sebastian A1 - Raack, Christian A1 - Baier, Georg A1 - Engel, Thomas T1 - Single-layer Cuts for Multi-Layer Network Design Problems T2 - Telecommunications Modeling Policy and Technology, also ZIB Report ZR-07-21 Y1 - 2008 UR - http://dx.doi.org/10.1007/978-0-387-77780-1_1 SP - 1 EP - 23 PB - Springer CY - College Park, MD, U.S.A. ER - TY - GEN A1 - Wessäly, Roland A1 - Werner, Axel A1 - Eckel, Klaus A1 - Seibel, Julia A1 - Orlowski, Sebastian A1 - Louchet, Hadrien A1 - Patzak, Erwin A1 - Bentz, Winfried T1 - Schätze heben bei der Planung von FTTx-Netzen: optimierte Nutzung von existierenden Leerrohren - eine Praxisstudie N2 - Das vom BMBF geförderte Projekt FTTX-PLAN entwickelt mathematische Modelle und Optimierungsverfahren, um automatisiert kostenoptimierte FTTx-Netze berechnen zu können. Wir zeigen anhand einer Praxisstudie in Zusammenarbeit mit der Regensburger R-KOM, wie ein Planer von diesen Verfahren profitieren kann, um die Auswirkungen bestimmter Entscheidungen auf die Netzstruktur und -kosten zu untersuchen. Wir illustrieren dies am Beispiel eines FTTB/FTTH-Vergleichs, der Variation von Kundenanbindungsraten und der gezielten Ausnutzung existierender Leerrohre, um Tiefbau zu vermeiden. T3 - ZIB-Report - 11-47 KW - Praxisstudie KW - Optische Zugangsnetze KW - Optimierung Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-14861 UR - http://www.vde-verlag.de/buecher/453339/breitbandversorgung-in-deutschland-itg-fb-227.html SN - 1438-0064 ER - TY - CHAP A1 - Bentz, Winfried A1 - Eckel, Klaus A1 - Louchet, Hadrien A1 - Orlowski, Sebastian A1 - Patzak, Erwin A1 - Seibel, Julia A1 - Werner, Axel A1 - Wessäly, Roland T1 - Schätze heben bei der Planung von FTTx-Netzen T2 - Breitbandversorgung in Deutschland Y1 - 2011 VL - 227 PB - VDE-Verlag ER - TY - CHAP A1 - Idzikowski, Filip A1 - Orlowski, Sebastian A1 - Raack, Christian A1 - Woesner, Hagen A1 - Wolisz, Adam T1 - Saving energy in IP-over-WDM networks by switching off line cards in low-demand scenarios T2 - Proceedings of the 14th conference on Optical network design and modeling Y1 - 2010 UR - http://portal.acm.org/citation.cfm?id=1834075.1834085 SP - 42 EP - 47 PB - IEEE Press CY - Piscataway, NJ, USA ER - TY - THES A1 - Orlowski, Sebastian T1 - Optimal Design of Survivable Multi-layer Telecommunication Networks N2 - Telecommunication transport networks consist of a stack of technologically different subnetworks, so-called layers, which are strongly interdependent. For example, one layer may correspond to an Internet (IP) backbone network whose links are realized by lightpath connections in an underlying optical fiber layer. To ensure that the network can fulfill its task of routing all communication requests, the inter-layer dependencies have to be taken into account already in the planning phase of the network. This is particularly important with survivability constraints, where connections in one layer have to be protected against cable cuts or equipment failures in another layer. The traditional sequential planning approach where one layer is optimized after the other cannot properly take care of the inter-layer dependencies; this can only be achieved with an integrated planning of several network layers at the same time. This thesis provides mathematical models and algorithmic techniques for the integrated optimization of two network layers with survivability constraints. We describe a multi-layer network design problem which occurs in various technologies, and model it mathematically using mixed-integer programming (MIP) formulations. The presented models cover many important practical side constraints from different technological contexts. In contrast to previous models from the literature, they can be used to design large two-layer networks with survivability requirements. We discuss modeling alternatives for various aspects of a multi-layer network and compare different routing formulations under multi-layer survivability constraints. We solve our models using a branch-and-cut-and-price approach with various problemspecific enhancements. This includes a presolving technique based on linear programming to reduce the problem size, combinatorial and sub-MIP-based primal heuristics to compute feasible network configurations, cutting planes which take the multi-layer survivability constraints into account to improve the lower bound on the optimal network cost, and column generation to generate flow variables dynamically during the algorithm. We develop techniques to speed up computations in a Benders decomposition approach and compare this approach to the standard formulation with a single MIP. We use the developed techniques to design large survivable two-layer networks by means of linear and integer programming methods. On realistic test instances with up to 67 network nodes and survivability constraints, we investigate the algorithmic impact of our techniques and show how to use them to compute good network configurations with quality guarantees. Most of the smaller test instances with up to 17 nodes can be solved to near-optimality. Moreover, we can compute feasible solutions and dual bounds even for large networks with survivability constraints, which has not been possible before. KW - Telekommunikationsnetze KW - Multi-layer-Netzen Ausfallsicherheit KW - gemischt-ganzzahlige Optimierung KW - Branch-and-cut-and-price KW - telecommunication networks KW - survivable multi-layer network design KW - mixed-integer programming KW - branch-and-cut-and-price Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11876 ER - TY - GEN A1 - Orlowski, Sebastian A1 - Pióro, Michal T1 - On the complexity of column generation in survivable network design with path-based survivability mechanisms N2 - This survey concerns optimization problems arising in the design of survivable communication networks. It turns out that such problems can be modeled in a natural way as non-compact linear programming formulations based on multicommodity flow network models. These non-compact formulations involve an exponential number of path flow variables, and therefore require column generation to be solved to optimality. We consider several path-based survivability mechanisms and present results, both known and new, on the complexity of the corresponding column generation problems (called the pricing problems). We discuss results for the case of the single link (or node) failures scenarios, and extend the considerations to multiple link failures. Further, we classify the design problems corresponding to different survivability mechanisms according to the structure of their pricing problem. Finally, we show that almost all encountered pricing problems are hard to solve for scenarios admitting multiple failures. T3 - ZIB-Report - 08-51 KW - Netzplanung KW - Dimensionierung KW - Spaltengenerierung KW - Mehrfachausfälle KW - survivable network design KW - routing KW - column generation KW - pricing KW - complexity Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11058 SN - 1438-0064 ER - TY - JOUR A1 - Raack, Christian A1 - Koster, Arie M.C.A. A1 - Orlowski, Sebastian A1 - Wessäly, Roland T1 - On cut-based inequalities for capacitated network design polyhedra JF - Networks Y1 - 2011 UR - http://onlinelibrary.wiley.com/doi/10.1002/net.20395/abstract VL - 57 IS - 2 SP - 141 EP - 156 ER -