Showing papers on "Network planning and design published in 1999"

Optical network design and restoration

Abstract: The explosion of data traffic and the availability of enormous bandwidth via dense wavelength division multiplexing (DWDM) and optical amplifier (OA) technologies make it important to study optical layer networking and restoration. This paper is concerned with fast distributed restoration and provisioning for generic mesh-based optical networks. We consider two problems of practical importance: determining the best restoration route for each wavelength demand, given the network topology and the capacities and primary routes of all demands, and determining primary and restoration routes for each wavelength demand to minimize network capacity and cost. The approach we propose for both problems is based on precomputing. For each problem, we describe specific algorithms used for computing routes. We also describe endpoint-based failure detection, message flows, and cross-connect actions for execution of fast restorations. Finally, we report test results for large carrier-scale networks that include both the computational performance of the optimization algorithms and the restoration speed obtained by simulation. Our results indicate that subsecond restoration, high capacity efficiency, and scalability can be achieved without fault isolation and with moderate processing. We also discuss methods for scaling algorithms to problems with very large numbers of demands. The wavelength routing and restoration algorithms, the failure detection, and the message exchange and activation architectures we propose are collectively known as WaveStar™ advanced routing platform.

Multicommodity Capacitated Network Design

Abstract: Network design models have wide applications in telecommunications and transportation planning; see, for example, the survey articles by Magnanti and Wong (1984), Minoux (1989), Chapter 16 of the book by Ahuja, Magnanti and Orlin (1993), Section 13 of Ahuja et al. (1995). In particular, Gavish (1991) and Balakrishnan et al. (1991) present reviews of important applications in telecommunications. In many of these applications, it is required to send flows (which may be fractional) to satisfy demands given arcs with existing capacities, or to install, in discrete amounts, additional facilities with fixed capacities. In doing so, one pays a price not only for routing flows, but also for using an arc or installing additional facilities. The objective is then to determine the optimal amounts of flows to be routed and the facilities to be installed.

On multimedia networks: self-similar traffic and network performance

Abstract: The main objective in telecommunications network engineering is to have as many happy users as possible. In other words, the network engineer has to resolve the trade-off between capacity and QoS requirements. Accurate modeling of the offered traffic load is the first step in optimizing resource allocation algorithms such that provision of services complies with the QoS constraints while maintaining maximum capacity. As broadband multimedia services became popular, they necessitated new traffic models with self-similar characteristics. We present a survey of the self-similarity phenomenon observed in multimedia traffic and its implications on network performance. Our current research aims to fill the gap between this new traffic model and network engineering. An immediate consequence of this study is the demonstration of the limitations or validity of conventional resource allocation methods in the presence of self-similar traffic.

A Mathematical Programming Model for Water Usage and Treatment Network Design

Abstract: A mathematical programming model is proposed in this paper for determining the optimal water usage and treatment network (WUTN) in any chemical plant, which features the least amount of fresh water consumption and/or minimum wastewater treatment capacity. In particular, because design equations of all wastewater treatment facilities and all units which utilize either process or utility water are included in the model, more comprehensive integration on a plant-wide scale can be achieved. In comparison with the available technologies, the proposed method is more reliable, more accurate, and much faster in synthesizing the WUTNs. Furthermore, more cost-efficient alternatives may be identified in certain design cases.

A branch-and-cut algorithm for capacitated network design problems

Abstract: We present a branch-and-cut algorithm to solve capacitated network design problems. Given a capacitated network and point-to-point traffic demands, the objective is to install more capacity on the edges of the network and route traffic simultaneously, so that the overall cost is minimized. We study a mixed-integer programming formulation of the problem and identify some new facet defining inequalities. These inequalities, together with other known combinatorial and mixed-integer rounding inequalities, are used as cutting planes. To choose the branching variable, we use a new rule called “knapsack branching”. We also report on our computational experience using real-life data.

Multimodal Express Package Delivery: a Service Network Design Application

Abstract: The focus of this research is to model and solve a large-scale service network design problem involving express package delivery. The objective is to find the cost minimizing movement of packages from their origins to their destinations, given very tight service windows, limited package sort capacity, and a finite number of ground vehicles and aircraft. We have developed a model for large scale transportation service network design problems with time windows. With the use of route-based decision variables, we capture complex cost structures and operating regulations and policies. The poor linear programming bounds limit our ability to solve the problem, so we strengthen our linear programming relaxation by adding valid inequalities. By exploiting problem structure using a specialized network representation and applying a series of novel problem reduction methods, we achieve dramatic decreases in problem size without compromising optimality of the model. Our solution optimization approach synthesizes column and row generation optimization techniques and heuristics to generate solutions to an express package delivery application containing hundreds of thousands of constraints and billions of variables, using only a small fraction of the constraint matrix. The results are potential savings in annual operating costs of tens of millions of dollars, reductions in the fleet size required, dramatic decreases in the time required to develop operating plans, and scenario analysis capabilities for planners and analysts. Through this and additional computational experiments, we conclude that, although state-of-the-art integer programming methods can work well for relatively small, uncongested service network design problems, they must be used in concert with heuristics to be effective for large-scale, congested problems encountered in practice.

System and method for analyzing and tuning a communications network

Abstract: A communications network is evaluated by selectively sending and receiving a plurality of network evaluation signals through the network. Responsive to these evaluation signals, selective network evaluation parameters are determined and stored. Responsive to these parameters, the response time and throughput characteristics of the network are determined by means of algebraic and queuing theory derivations. Network response time analysis determines the apparent bandwidth, utilization, internal message size, queue factor, and device latency. Throughput analysis defines, calculates, and uses hop count, duplex, throughput and multi-server factors. Service level and capacity planning provides comprehensive “what-if” network planning facilities, including calculation of the change in network traffic before network response time service level is compromised; calculation of the additional file load capacity of the network; and determination of tuning recommendations for recommended window size for file transfer to fill remaining capacity.

Method and system for diagnosing network intrusion

Abstract: A method and system are disclosed for analyzing traffic on a network by monitoring network traffic and, when a particular network condition (for example, a network attack) is detected, gathering information about the traffic on the network by launching an agent and having the agent iteratively identify which of the links on the node on which the agent operates accepts a type or class of traffic, traverse the identified link to the node across the link, and repeat the process.

Broadband Network Traffic: Performance Evaluation and Design of Broadband Multiservice Networks: Final Report of Action Cost 242

Abstract: From the Publisher: This coherently structured and authorative text is the final report of the European Action COST 242, devoted to advancing research in the field of multiservice network design and performance evaluation. The excellent results presented are largely based on some 240 action reports compiled in cooperation between researchers from academia and professionals from industry and discussed during the COST 242 meetings.

Frequency Assignment Problems

Abstract: The term frequency assignment has been used to describe many types of problems which, quite often, have different modeling needs and objectives. These problems include: 1. Planning models for permanent spectrum allocation, licensing, and regulation which maximize utilization of all radio spectra [94]. 2. Planning models for network design within a given allocation to include; aeronautical mobile, land mobile, maritime mobile, broadcast, land fixed (point-to-point) and satellite. 3. On-line algorithms for dynamically assigning frequencies to users within an established network. Of special interest here are land cellular mobile systems, where an enormous amount of research has been done. A paper by Katzela and Naghshineh [55] contains nearly 100 references to works just in cellular dynamic channel assignment.

A QoS-Provisioning neural fuzzy connection admission controller for multimedia high-speed networks

Abstract: This paper proposes a neural fuzzy approach for connection admission control (CAC) with QoS guarantee in multimedia high-speed networks. Fuzzy logic systems have been successfully applied to deal with traffic-control-related problems and have provided a robust mathematical framework for dealing with real-world imprecision. However, there is no clear and general technique to map domain knowledge on traffic control onto the parameters of a fuzzy logic system. Neural networks have learning and adaptive capabilities that can be used to construct intelligent computational algorithms for traffic control. However, the knowledge embodied in conventional methods is difficult to incorporate into the design of neural networks. The proposed neural fuzzy connection admission control (NFCAC) scheme is an integrated method that combines the linguistic control capabilities of a fuzzy logic controller and the learning abilities of a neural network. It is an intelligent implementation so that it can provide a robust framework to mimic experts' knowledge embodied in existing traffic control techniques and can construct efficient computational algorithms for traffic control. We properly choose input variables and design the rule structure for the NFCAC controller so that it can have robust operation even under dynamic environments. Simulation results show that compared with a conventional effective-bandwidth-based CAC, a fuzzy-logic-based CAC, and a neural-net-based CAC, the proposed NFCAC can achieve superior system utilization, high learning speed, and simple design procedure, while keeping the QoS contract.

Signalling method and conversion device for telecommunications networks

Abstract: A signalling method and conversion device for telecommunications networks, for example mobile networks such as GSM or UMTS networks, wherein at least certain subscribers can register in their home network, or in a telecommunications network having a roaming agreement with the operator of their home network, using a first subscriber identification from the number area of their home operator, certain of these subscribers being assigned a second subscriber identification from the number area of a partner network operator with which these subscribers can register in a visited network with which operator their home network operator does not have a roaming agreement, the signalling traffic concerning subscribers who have been registered in such a visited network with a second subscriber identification number being conducted to the partner network, being filtered there, and being rerouted to their home network, and signalling traffic concerning such subscribers received in said partner network from said home network being rerouted to this said visited network.

Minimal cost coverage planning for single frequency networks

Abstract: OFDM based single frequency networks (SFNs) have been standardized for terrestrial broadcasting systems, for digital audio broadcasting (DAB) as well as for digital video broadcasting (DVB). Due to the multipath tolerance of the OFDM scheme, the receiver is able to combine signals coming from several transmitters, despite of the varying propagation delays, i.e., heavy artificial multipath propagation. In order to take full advantage of the diversity gain provided by the SFN architecture, proper network design is required. We focus on the cost efficient design of an SFN providing broadcasting services over a predefined service area with requirements both on the received signal quality and on the allowable interference level experienced by existing services in the same spectrum. We formulate the problem as a discrete optimization problem, where the network design parameters such as power, antenna heights and transmitter locations are the decision variables. The general stochastic optimisation algorithm simulated annealing has been adapted for solving the above problem. The novelty of our method is that cost factors and interference constraints are embedded in the optimisation procedure. Through numerical examples we demonstrate that significant reduction in network cost can be achieved by our approach.

Network+ Guide to Networks

Abstract: Knowing how to install, configure, and troubleshoot a computer network is a highly marketable and exciting skill This book first introduces the fundamental building blocks that form a modern network, such as protocols, topologies, hardware, and network operating systems It then provides in-depth coverage of the most important concepts in contemporary networking, such as TCP/IP, Ethernet, wireless transmission, and security After reading the book and completing the end-of-chapter exercises, you will be prepared to select the best network design, hardware, and software for your environment You will also have the skills to build a network from scratch and maintain, upgrade, and troubleshoot an existing network Finally, you will be well prepared to pass CompTIAs (the Computing Technology Industry Associations) Network+ certification exam This book explains concepts logically and in a clear, approachable style In addition, concepts are reinforced by real-world examples of networking issues from a professionals standpoint Each chapter opens with an On the Job story from a network engineer These real-world examples, along with Hands-on Projects and Case Projects in each chapter, make this book a practical learning tool The numerous tables and illustrations, along with the glossaries, appendices, and study questions make the book a valuable reference for any networking professional

Reconfigurable, intelligent signal multiplexer and network design and maintenance system therefor

Abstract: A modular, reconfigurable, intelligent signal multiplexer for telecommunications purposes includes a rack or shelf adapted to support a plurality of printed circuit cards. The cards include feature cards and line cards, and at least one central controller card. All of the cards includes backplane connectors to connect to customer premises equipment and to telecommunications lines, and midplane connectors to interconnect all of the circuit cards for data exchange under program control. Each feature card contains an embedded microprocessor with associated embedded operating system, as well as RAM memory and flash RAM. The signal multiplexer processes digital inputs from a wide range of user equipment for transmission over digital facilities, including T1 and T3 lines. The system employs an Advanced Intelligent Multiplexer Network software package to perform network configuration and SNMP to obtain performance reports, statistics collection and alarm monitoring. SNMP is accessed through a software package having an intuitive graphical interface for network planning and design, routing and inventory-management support. The functions of the signal multiplexers are controlled by a mapping scheme. A map change alters the circuit-to-time slot assignments. A large number of maps may be stored by the system, and may be set to start running in response to user-specified times, a predetermined event, an alarm, or a manual keyboard command. The graphical interface also presents screen displays that enable network design, node configuration, and alteration of an existing network.

Wireless integrated network sensors: toward low-cost and robust self-organizing security networks

Abstract: A very important benefit of continuing advances in CMOS IC technology is the ability to construct a wide variety of micro electrical mechanical systems (MEMS), including sensors and RF components. These building blocks enable the fabrication of complete systems in a low-cost module, which include sensing, signal processing, and wireless communications. Together with innovative and focused network design techniques that will make possible simple deployment and sustained low- power operation, the small size and cost can be enabling for a very large number of law enforcement and security applications, including remote reconnaissance and security zones ranging from persons to borders. We outline how the application can be exploited in the network design to enable sustained low-power operation. In particular, extensive information processing at nodes, hierarchical decision-making, and energy conserving routing and network topology management methods will be employed in the networks under development.

Reliability Issues In Telecommunications Network Planning

Abstract: Given a set of geographically distributed sites, information about the traffic between them, and information about the means by which they can be connected (links), the network design problem is to select some of the candidate connections. The goals in this selection typically include keeping the cost within a specified budget and providing sufficient connections to support the traffic offered at a specified capacity, speed, or throughput. Of course, the wide variety of traffic types and patterns, and of means of connection, results in a significant range of network design problems.

Evaluation of electricity distribution system design strategies

Abstract: The paper describes a statistical approach and the developed software tool for the cost evaluation of alternative distribution network design strategies. In contrast to traditional approaches to optimal network design, which are based either on the analysis of a small specific service area or on idealistic networks, the proposed method determines optimal network design polices by evaluating alternative strategies on many statistically similar networks. The software can generate a number of realistic consumers sets that are characteristic for urban and rural areas, in terms of consumer distributions, types, numbers etc. These sets are then supplied by a large number of different networks following several alternative design strategies. Evaluating the cost of each particular design over a number of statistically similar networks allows statistically significant conclusions to be drawn. Simulations have been carried out on a single voltage level and on two voltage levels, considering different load densities and the use of underground cable and indoor substations or overhead line and outdoor substations. The results have been analysed to give an indication of the optimum electricity distribution design policy in terms of the cost of equipment, its installation and maintenance, and variable and fixed losses. The software is currently being used at one of the UK electricity companies to review distribution network design.

Network design in supply chain management

Abstract: The distribution function in a supply chain is an important internal service function for any firm, and has been increasingly recognized as playing a strategic role in achieving competitive advantage. This paper proposes improving the distribution function of the supply chain by employing hub‐and‐spoke network designs. Such designs have proven to be effective with third party logistics carriers such as Federal Express, UPS, Norfolk Southern, and Yellow Freight. Several models and heuristic solution techniques have been introduced in the literature in the past ten years. However, the performance of such heuristics, under different transportation environments, has not been examined. This paper acts as a first step in this direction. The performance of two heuristics to solve a hub‐and‐spoke network is compared against the performance of an optimal technique, for various configurations of data. With the results of this study, business managers can, by analyzing the structure of their data, assess the “risk” associated with applying one of the two heuristics. Heuristic developers can also exploit the results of this study to give them insight into areas where heuristics can be developed or strengthened in order to give rise to more robust heuristics.

Application of statistical and neural approaches to the daily load profiles modelling in power distribution systems

Abstract: Load modelling is an essential task in the economic analysis, operation and planning of distribution systems. Particularly, when a demand side management system is taken into account on a deregulated energy market, the knowledge of load profiles is of the greatest importance. Forecasting of daily demand, based upon load models, uses comparable load research data for a different customer mix. For the given season and day of the week, the shape of a daily load curve depends mainly on the customer composition. Difficulties in defining objective customer classes significantly complicate the forecasting process. Usage of statistical clustering and neural network approaches makes possible to improve the load modelling accuracy. This paper presents load modelling methods useful for the long-term planning of power distribution systems. The theoretical statement is illustrated by examples which correspond to Polish and German distribution systems.

Network design in reverse logistics : a quantitative model

Abstract: The introduction of (extended) producer responsibility forces Original Equipment Manufacturers to solve entirely new managerial problems. One of the issues concerns the physical design of the reverse logistic network, which is a problem that fits into the class of facility-location problems. Since handling return flows involves a lot of different processing steps, the physical system might consist of two or more echelons. In this paper, a MILP-model is presented that gives decision support in designing the physical network structure of a multi-echelon reverse logistic system. The model is applied to a case from the automotive industry. The general applicability of the model in logistic network design is discussed. Finally, subjects for further research are pointed out.

A PCS network with correlated arrival process and splitted-rating channels

Abstract: The arrival of calls (i.e., new and handoff calls) in a personal communications services (PCS) network are modeled by a Markov arrival process (MAP) in which we allow correlation of the interarrival times among new calls, among handoff calls, as well as between these two kinds of calls. Each cell of the network consists of a finite number of channels and a buffer with finite size for handoff calls. There exist some channels among each cell which can be used by splitting the original rate into two channels with different rates if necessary when a handoff call arrives and finds all the channels busy. We obtain the stationary joint probability of number of calls in the cell and the phase of the arrival process, the blocking probability of a new call, the forced termination probability of a handoff call, and the mean dwell time of a handoff call in the buffer. Finally, we obtain the distribution and the mean of the cell's busy period, the distribution and the mean of the first time to split the cth channel, and some other interesting performance measures for the network. Some explicit results for special cases obtained by Lin et al. (see IEEE Trans. Vech. Technol., vol.45, no.1, p.122-30, 1996 and vol.43, no.3, p.704-12, 1994), Tekinary et al. (1992) and by Yoon et al. (1993) can also be directly obtained from the general conclusion. The results presented can provide guidelines for field data processing in PCS network design and performance evaluation.

Genetic algorithm for solving bicriteria network topology design problem

Abstract: Increasing attention is being paid to various problems inherent in the topological design of network systems. The topological structure of these networks can be based on service centers, terminals (users), and connection cables. Lately, these network systems have been designed with fiber optic cable, due to increasing user requirements. But considering the high cost of the fiber optic cable, it is desirable that the network architecture is composed of a spanning tree. Network topology design problems consist of finding a topology that optimizes design criteria such as connection cost, message delay, network reliability, and so on. Recently, genetic algorithms (GAs) have advanced in many research fields, such as network optimization problems, combinatorial optimization, multi-objective optimization, and so on. Also, GAs have received a great deal of attention concerning their ability as an optimization technique for many real-world problems. In this paper, a GA for solving bicriteria network topology design problems of wide-band communication networks connected with fiber optic cable is presented, considering network reliability. We also employ the Prufer number and cluster string in order to represent chromosomes. Finally, we present some experiments in order to certify the quality of the network designs obtained by using the proposed GA. From the results, the proposed method can search effectively better candidate network architecture.

Survivable Network Design: The State of the Art

Abstract: In the past few years the telecommunications industry has undergone significant changes. We are rapidly evolving to a state where audio/visual and data traffic is all provided on the same networks. Telecommunication companies are investing billions of dollars in the design and maintenance of telecommunication networks to provide the users with the better quality of service that they have begun to expect. Due to their high capacity, fiber optic cables have become the medium of choice in the deployment of such new networks worldwide. Such high capacities encourage telecommunication providers to create networks that are substantially more sparse than previous copper based networks. Unfortunately, with sparsity comes vulnerability to failure. Given the dependence on the varied services offered by the modern networks, the magnitudes of the investments involved and the costs of disasters it is only logical that researchers look at problems in survivable network design as an interesting research question. There have been a number of papers that have addressed these and other related issues. In this paper we try to classify the area of survivable network design and provide a classification scheme for the same.

Design and Dimensioning of Survivable SDH/Sonet Networks

Abstract: Basically, a telecommunications network may be represented as a graph where the edges correspond to transmission cables carrying information (signals) between nodes that represent users. Associated to each pair of users there is an integer valued traffic demand which must flow through this network. Building a network in which all customers are directly connected to one another is clearly not a realistic solution due to the huge amount of cables needed to convey all the demands. Consequently, individual signals are grouped into larger aggregate signals, also called frames, and high capacity transmission equipments may then be used to transport demands more efficiently. In technical language, this grouping operation is called multiplexing and the opposite operation which consists in extracting initial information from a high capacity frame is called demultiplexing.

Future transport network architectures

Abstract: The architecture of today's long distance transmission networks, which we call the baseline architecture, is a complex and multilayered hierarchy of TDM circuits. One premise of the baseline architecture is that restoration from network failures is provided mostly by SONET/SDH rings. This article presents an alternative architecture that uses ATM and optical layer cross-connect technology for TDM services. Using a sophisticated set of network design tools developed at AT&T Labs-Research, we show that the alternative architecture offers dramatic capital savings and improved network efficiency over the baseline architecture. Most of this savings can be attributed to use of OLXC mesh network restoration, which makes more efficient use of capacity than SONET/SDH rings, and use of ATM switching for transport of TDM circuits, which consolidates the numerous TDM equipment layers inherent to the baseline architecture. In addition, motivated by the rapid growth of IP services, we analyze in the alternative architecture whether to provide restoration for IP services in the IP layer itself, by rerouting packets over precalculated restoration paths with MPLS, or to alternatively provide restoration of failed IP layer links in the OLXC layer. One potential advantage of IP layer restoration is that network operators may choose to only restore a fraction of the services, in particular the "priority" services, affected by a network failure. This article gives some methodology of how to determine this fraction at which IP layer restoration is cost-competitive with OLXC restoration.