Showing papers on "Network planning and design published in 1983"

Techniques for Packet Voice Synchronization

Abstract: Packet switching has been proposed as an effective technology for integrating voice and data in a single network. An important aspect of packet-switched voice is the reconstruction of a continuous stream of speech from the set of packets that arrive at the destination terminal, each of which may encounter a different amount of buffering delay in the packet network. The magnitude of the variation in delay may range from a few milliseconds in a local area network to hundreds of milliseconds in a long-haul packet voice and data network. This paper discusses several aspects of the packet voice synchronization problem, and techniques that can be used to address it. These techniques estimate in some way the delay encountered by each packet and use the delay estimate to determine how speech is reconstructed. The delay estimates produced by these techniques can be used in managing the flow of information in the packet network to improve overall performance. Interactions of packet voice synchronization techniques with other network design issues are also discussed.

Multichannel Local Area Network Protocols

Abstract: Multiple-access protocols suitable for packet switching local area networks that use several parallel broadcast channels are presented and analyzed by evaluating their throughput and delay characteristics. The local network architecture is first described, then the network performances are evaluated considering a variety of multiple-access schemes that are derived from CSMA and CSMA-CD protocols, by extending the original single channel schemes to a multiple channel system. It is shown that significant performance improvements are achievable with the multiple channel option. Further advantages obtained with the proposed network architecture are a higher reliability and fault tolerance, and a modular network design that allows a gradual system growth following users' demands.

Fuzzy-Network Planning - FNET

Abstract: Currently used network planning techniques, such as PERT/CPM and their derivatives, assume that, in a graph of known structure, the duration of its activities is known either with certitude or at least with some probability. However, in many applications the structure of the graph and the duration of its activities are imprecise. This paper shows how the application of fuzzy sets to such problems can yield quasi-deterministic results obtained from imprecise Input data.

Centralized teleprocessing network design

Abstract: The problem considered is that of finding an optimal (minimum cost) design for a centralized processing network given a set of locations, traffic magnitudes between these locations, and a single common source or destination. Several heuristics, which are efficient (in terms of their execution time and memory requirements on a digital computer) and which produce seemingly good results, have already been developed and are currently accepted techniques. Some work has also been done on finding optimal solutions to this problem both as a design tool and as a means of verifying the effectiveness of proposed heuristics. We focus on this latter area. Currently known techniques for the optimal solution of this problem via integer programming have fallen short of the desired objectives as they require too much memory and running time to be able to treat problems of realistic size and complexity. We develop an improved technique which is capable of handling more realistic problems.

Network design application of an extraction algorithm for network aggregation.

Abstract: The performance of a network extraction algorithm is described, and the algorithm is tested by using the network design problem. A network is chosen as the original network and is aggregated at different levels. The results of the optimal decision making under a common set of alternative actions are then compared against the original and the aggregated networks. The results suggest that the network aggregation algorithm is a useful tool in simplifying networks to reduce the computational burden associated with the network design problem, and to allow a broader range of policy options to be tested in a fixed amount of computer time than would be allowed by using the original disaggregated network. (Author)

Multicriteria spatial price equilibrium network design: theory and computational results

Abstract: In this paper we consider the problem of determining the optimal design of a transportation network using a vector valued criterion function when the flow pattern is assumed to correspond to a spatial price equilibrium. This problem arises in rail and freight network design, where the spatial price equilibrium is a better behavioral description than the Wardropian user equilibrium characteristic of urban transportation applications. We describe two alternative heuristic solution techniques for the multicriteria spatial price equilibrium network design problem. The first is based on iteration between a pure spatial price equilibrium model and a vector optimization model with only nonnegativity constraints. The second solution technique employs the Hooke and Jeeves algorithm for nonlinear programming to solve a vector optimization model with implicit constraints guaranteeing a spatial price equilibrium flow pattern. In these solution procedures, rather than represent the equilibrium problem as a mathematical program, as is normally done for the Wardropian traffic assignment problems used in urban applications, we employ an original nonlinear complementarity formulation of the spatial price equilibrium problem written entirely in terms of nodal and arc variables and solved extremely efficiently through the iterative application of a linear complementarity algorithm. The nonlinear complementarity formulation allows us to address problems with asymmetric transportation cost, commodity demand and commodity supply functions without the specialized diagonalization/relaxation algorithms required by other approaches.

Optimization of Gravity‐Fed Water Distribution Systems: Theory

Abstract: A method is developed for the optimal design of multisource, looped, gravity‐fed water distribution systems subjected to a single loading pattern. The method is based on linear programming (LP) techniques and produces a locally optimal solution. Initially, design feasibility constraints are derived to check whether network design and therefore network optimization is feasible. Based on classical transportation problem principles, a theory is developed to formulate an LP problem for obtaining design paths from the source nodes to the demand nodes and thereby for obtaining the design distribution graph for the entire distribution system. Separate LP optimization models are then formulated to deal with the either the D‐specified condition in which the nonprimary links are of some minimum or specified diameter, or the Q‐specified condition in which the nonprimary links carry some minimum or specified discharge. The proposed method is illustrated through a design example in an accompanying paper dealing with a...

Sequential Network Design Using Extra Inputs for Fault Detection

Abstract: In order to enhance fault-detection capability, extra inputs are used when designing sequential machines. Here, a technique is proposed that designs these machines, precisely with the use of extra inputs-so as especially to minimize the length of the checking sequence. The resulting checking sequences are shown to be upper bounded by (3 + 2n)m + rn (3m + 1), where n is the number of states, r is the number of inputs, m = log, n, and s is the number of extra inputs, respectively. The technique presented here also provides a procedure to construct directed graphs with a minimum diameter.

Lower planes for the network design problem

Abstract: A new class of relaxations for the network design problem based on lower planes, i.e., linear lower approximations of the objective function, is introduced. Such relaxations provide lower bounds much sharper than the bounds used so far in branch and bound algorithms for this problem.

Interaction of Network Design and Fiber Optic Component Design in Local Area Networks

Abstract: This paper discusses some of the system issues that impact the design of fiber optic components intended for use in local area networks. How fiber optics technology affects system level decisions such as topology and system synchronization is also discussed. Finally, some of the key contributions of fiber optics in local network applications as well as areas for further contribution are presented.

Data Communication Networks

Abstract: This chapter discusses the various forms of data communication networks and the types of communication channels that have an influence on the network design. With data communication networks, connections are organized on the principles of point-to-point (PTP) connection, even though other network structures are available. As the data is in digital form, it may be stored and processed en route by computers in a technique known as store-and-forward (SAF). While point-to-point is defined as the method of direct communication between two points, store-and-forward is defined as a method of communication in which the messages may be received at intermediate routing points and stored. The messages are then transferred directly or with further network points with interim storage, each in accordance with its own address. In the case of SAF, there is no direct connection between the distant points when they are so-called communicating, but the messages are stored in the network nodes and are retransmitted in the channels only when such a channel has free time to accept the messages. Store-and-forward systems can provide means of efficiently exploiting the communication channels by ensuring smooth and continuous flow of data.

Total Network Data System: Theoretical and engineering foundations

Abstract: The Total Network Data System (TNDS) is a coordinated family of computer-based systems that collect and process network measurements to aid the engineers, administrators, and managers of the Bell System network in efficiently meeting service objectives. This paper describes these service objectives, the nature of telephone traffic and traffic measurements, and the theories and engineering assumptions underlying the use of these measurements in the design and administration of the trunk network and switching systems.

Simple Constructions for Multiterminal Network Flow Synthesis

Abstract: The multi-terminal network flow synthesis problem is one of the few nicely solved problems in network design, and is used widely in courses and texts on combinatorial optimization as an example of an elegantly solved problem. The solution used in these texts is due to R. E. Gomory and T. C. Hu. We present two simpler algorithms which improve the original method in speed, simplicity of the needed data structures and, most importantly, in the simplicity of the networks that are constructed. The networks constructed are planar and “uniformly optimal,” permit simple flow routing methods and simple solutions to many sensitivity and postoptimality questions, and have as few edges as any networks produced by the Gomory-Hu method. Further, one algorithm constructs networks with only one node of degree larger than three, while the other algorithm constructs networks in which no node has degree greater than four.

Implementing the ISO-OSI reference model

Abstract: The ISO-OSI reference model was the design framework for the implementation of a heterogeneous network in a local environment. The HMINET-2 is a network based on standards in data communication. The paper focus on the OSI model feasability and outlines the encountered problems and the adopted solutions in the network design and implementation.

Design of multistage interconnection networks

Abstract: Interconnection networks have extensive applications in switching and reconfigurable multiprocessor systems. A number of multistage networks which can achieve a limited number of permutations have been discussed in the literature [1]. On the other hand, rearrangeable networks [6] have the property that any idle input/output pair can be connected. In most parallel-processing applications, a specified set of input/output connection patterns are required. Often these patterns cannot be achieved by networks like shuffle exchange, cube, Omega and baseline. The chief objective of the paper is to present a methodology for multistage interconnection network design. This design generally requires less switching elements than the rearrangeable network. The paper relies on the formulation of a transmittance matrix for the network. The properties of this matrix are studied with particular focus on rearrangeable networks. A control algorithm which determines the switch states required to achieve a particular permutation is established. The switching algebraic approach is particularly well suited to address the network design problem, because the switch states are explicitly exhibited in the transmittance matrix.

Theory of network planning for laboratory research and development.

Abstract: Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT) are quantitative network planning strategies that facilitate management of projects with many interrelated activities. They determine the minimum time necessary to complete a project and identify which activities are critical to achieving the minimum. PERT also incorporates probabilistic estimates of activity durations. This statistical approach is useful when planning a project entailing some uncertainty and allows one to calculate chances of finishing on time. CPM and PERT encourage participation of all key personnel in the planning process, effective fit between project variables and organizational structure, and optimization of resource allocation. Availability of several levels of sophistication make network planning flexible enough to be applied easily in laboratory research and development. Iterative refinement of network plans and time estimates in progressive steps of involvement with clinical colleagues augments the effectiveness of these technics in hospital settings.

Identification in computer networks

Abstract: To communicate across a network system, entities within the system need to be able to identify one another. An identifier usually takes the form of a name or an address. Conventions for the assignment of these identifiers and their resolution affect many aspects of network design. Identification is thus a crucial issue for network architecture and standardization. In this paper, our discussion is first devoted to the semantics of names, addresses, and routes, with emphasis on the relationships among them. We then examine the implications of layered network architecture, syntactic differences of identifiers, and broadcast communication. Finally, we turn our attention to naming and addressing in large dynamic networks.

Internetting between VAX and Apollo ring network

Abstract: Specifications for a network design to connect the Apollo DOMAIN network with the VAX system are discussed in this paper. Three networking approaches were considered which represent three distinct chronological stages in the evolution of computer communications. Based on a comparison of data transfer rate and the installation cost among these three alternatives, the LAN, represented by the Ethernet, was recommended as the connecting hardware.The OSI Reference Model was used as a starting basis to discuss protocol issues to be built for the chosen LAN. Of particular interest are the transport, presentation, and application layers. The transport layer was designed to perform functions of the network and session layers in the OSI model. The presentation layer incorporated a text mapping algorithm to convert incompatible characters in filenames created on the VAX versus those on the Apollo. The application layer was designed with the capability to send and receive files between these two systems.

Communications network design and costing model technical manual

Abstract: This computer model provides the capability for analyzing long-haul trunking networks comprising a set of user-defined cities, traffic conditions, and tariff rates. Networks may consist of all terrestrial connectivity, all satellite connectivity, or a combination of terrestrial and satellite connectivity. Network solutions provide the least-cost routes between all cities, the least-cost network routing configuration, and terrestrial and satellite service cost totals. The CNDC model allows analyses involving three specific FCC-approved tariffs, which are uniquely structured and representative of most existing service connectivity and pricing philosophies. User-defined tariffs that can be variations of these three tariffs are accepted as input to the model and allow considerable flexibility in network problem specification. The resulting model extends the domain of network analysis from traditional fixed link cost (distance-sensitive) problems to more complex problems involving combinations of distance and traffic-sensitive tariffs.

Network Design Tool for EHF Satellite Communications Networks

Abstract: : This document describes the design concept of the Network Design Tool. The Network Design Tool (NDT) is a collection of analytical techniques, algorithms and simulation methods that may be used to characterize the performance of a computer communication network. Much work has been done over the past several years in network performance analysis and many techniques have been developed or proposed. Each of these methods applies to a particular aspect of the network design and is based on a particular modeling point of view. We define the computer communication network and then describe the different ways the network may be modeled. Each network model is related to the particular design problem being addressed. The various analytical approaches are briefly described and their relationship to the network models discussed. Chapter 2 is a survey of the major approaches to specific network design problems while Chapters 3 and 4 discuss two fairly well defined areas of network analysis: topological design/optimization and protocol validation. Chapter 5 is a survey of network design tools presently available locally or on the Advanced Research Projects Agency Network (ARPANET). Finally, Chapter 6 presents an outline of the NDT specification.