In network design, the gap between theory and practice is woefully broad. This book narrows it, comprehensively and critically examining current network design models and methods. You will learn where mathematical modeling and algorithmic optimization have been under-utilized. At the opposite extreme, you will learn where they tend to fail to contribute to the twin goals of network efficiency and cost-savings. Most of all, you will learn precisely how to tailor theoretical models to make them as useful as possible in practice. Throughout, the authors focus on the traffic demands encountered in the real world of network design. Their generic approach, however, allows problem formulations and solutions to be applied across the board to virtually any type of backbone communication or computer network. For beginners, this book is an excellent introduction. For seasoned professionals, it provides immediate solutions and a strong foundation for further advances in the use of mathematical modeling for network design. (Less)

Routing, Flow, And Capacity Design In Communication And Computer Networks

Modern society depends on the operations of civil infrastructure systems, such as transportation, energy, telecommunications, and water. These systems have become so interconnected, one relying on another, that disruption of one may lead to disruptions in all. The approach taken in this research is to model these systems by explicitly identifying these interconnections or interdependencies. Definitions of five types of infrastructure inter-dependencies are presented and incorporated into a network flows mathematical representation, i.e., an interdependent layer network model. Using the lower Manhattan region of New York, for illustrative purposes, the implementation of the model is shown. First, the data requirements are presented with realistic data on the interdependent infrastructure systems of power, telecommunications, and subways. Next, a scenario is given that causes major disruption in the services provided by these infrastructures and demonstrates the use of the model in guiding restoration of services. The paper concludes with a discussion of accomplishments and opportunities for future work.

Restoration of Services in Interdependent Infrastructure Systems: A Network Flows Approach

Hub location in backbone/tributary network design: a review

This paper considers an integrated service network design problem for a given set of freight demands that is concerned with integration of locating cross-docking (CD) centers and allocating vehicles for the associated direct (transportation) services from origin node to a CD center or from a CD center to the destination node. For the vehicle allocation, direct services (sub-routes) should be determined for the given freight demands, and then the vehicle allocation has to be made in consideration of routing for the associated direct service fulfillment subject to vehicle capacity and service time restriction. The problem is modeled as a path-based formulation for which a tabu-search-based solution algorithm is proposed. To guarantee the performance of the proposed solution algorithm, strong valid inequalities are derived based on the polyhedral characteristics of the problem domain and an efficient separation heuristic is derived for identifying any violated valid inequalities. Computational experiments are performed to test the performance of the proposed solution algorithm and also that of a valid-inequality separation algorithm, which finds that the solution algorithm works quite well and the separation algorithm provides strengthened lower bounds. Its immediate application may be made to strategic (integrated) service network designs and to tactical service network planning for the CD network.

Integrated service network design for a cross-docking supply chain network

http://yoksis.bilkent.edu.tr/doi_getpdf/articles/10.1016-j.cor.2004.05.009.pdf

Solving the hub location problem with modular link capacities

In this article we propose a mixed 0-1 linear programming model for the topological network design problem with modular switches such as the ones that will be used in asynchronous transfer mode (ATM) frame relay and other broadband networks. The model includes the location of switches, their configuration with respect to ports and multiplexers, the design of an access network with a star topology, and a backbone network with a fixed topology (ring or tree). To obtain a solution, we propose a greedy heuristic that provides a good starting solution, and a tabu search heuristic to improve the solution. Finally, we present an example of the application of the heuristics and results for a set of randomly generated problems with up to 500 users and 30 potential switch sites. For the hundreds of problems generated, the tabu algorithm produced solutions that were, on average, within 1.5% of the optimal solution, and in the worst case within 4.95% of the optimal solution.

Topological Design of Two-Level Telecommunication Networks with Modular Switches

On the Design Problem of Multitechnology Networks

In this article we propose a model for the topological design problem of multitechnology networks that includes the location of switches and their port configuration, the design of an access network (with single and double access links) and a backbone network. The model specifically takes into account different types of modular switches where each type is characterized by its cost, its capacity in terms of the number of slots, and by its switch fabric capacity. The mutitechnology qualifier stems from the fact that several technologies and rates can be used in the access network. The proposed model is of the integer-programming variety, and in order to find a good solution, we propose a starting heuristic that provides an initial solution and the tabu-search algorithm to improve the solution. Lower bounds are proposed and used to assess the performance of the tabu-based approach. Numerical results for randomly generated problems with up to 500 clients and 50 potential switch sites are presented. The tabu-search algorithm produced solutions that were, on average, within 2.11% of the best lower bound.

This paper presents a mixed 0–1 linear programming model for the metropolitan area network (MAN) expansion problem. The model includes the location of new switch sites, the update of the configuration of the switches (with respect to port and shelf types), the update of the access network, and the expansion of the backbone (core) network. In addition, we consider that several technologies (e.g., frame relay and asynchronous transfer mode) and rates (e.g., OC-3 and OC-12) may be used in the access network. A multiple-ring topology is chosen for the backbone network since it is sparse, therefore not too expensive, while providing protection against single-link or switch failure. To find a good solution, we propose an initial heuristic that provides a starting solution and a tabu–based heuristic to improve the solution. Finally, we present an illustrative example of a MAN design with its successive expansions, followed by a systematic set of experiments designed to assess the performance of the proposed algorithms. © 2000 John Wiley & Sons, Inc.

S Chamberland

Papers

Topological Design of Two-Level Telecommunication Networks with Modular Switches

On the Design Problem of Multitechnology Networks

On the Design Problem of Multitechnology Networks

Topological expansion of multiple-ring metropolitan area networks

Tabu Search and Post-Optimization Algorithms for the Topological Update of Two-Level Networks with Modular Switches