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Selected Areas in Communications, IEEE Journal on

Issue 8 • Date Oct 1989

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Displaying Results 1 - 11 of 11
  • Impact of emerging switching-transmission cost tradeoffs on future telecommunications network architectures

    Page(s): 1207 - 1218
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1068 KB)  

    A study conducted to better understand the impact of declining transmission costs on the design of future fiber-based telecommunications network architectures is described. The study consists of quantifying the costs of switches, trunk and loop plant, building, and outside plant enclosures in order to determine the most economical number of switching nodes in the study areas based on the current equipment and land/building prices as well as the expected prices in the 1995 time frame. The results of this study show that the network architectures with fewer but larger switching nodes accompanied by back hauling of traffic via fiber optics and large multiplexers/concentrators offer significant savings potential in rural/suburban areas and low-to-moderate savings in urban areas as compared to architectures with many smaller switching nodes. In a broadband network environment, the results are shown to be valid for small penetrations of broadband services (less than 10%) and small broadband call bandwidths (equal to or less than 45 Mb/s) View full abstract»

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  • Topology design and bandwidth allocation in ATM nets

    Page(s): 1253 - 1262
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB)  

    The design of a P/S network embedded into a backbone facility network is discussed. The problem is formulated as a network optimization problem where a congestion measure based on the average packet delay is minimized, subject to capacity constraints posed by the underlying facility trunks. The variables in this problem are the routing on the express pipes (i.e. the channels that interconnect the P/S modes) and the allocation of bandwidth to such pipes. An efficient algorithm is presented for the solution of the above problem and it is applied to some representative examples. It is shown that for some test cases the congestion measure is substantially reduced with respect to the values obtained when the embedded topology is kept identical to the backbone topology. Dynamic reconfiguration schemes where the embedded topology is periodically adjusted to track the fluctuations in traffic requirements are discussed View full abstract»

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  • Strategic telecommunications networks planning in the context of emerging technologies, architectures, and services

    Page(s): 1198 - 1206
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    A methodology is presented for conducting strategic network planning studies under a new set of planning assumptions. The key element of the described methodology is a mathematical model of the equipment-replacement decision-making process that explicitly captures the economic impact of emerging technologies, architectures, and services. The general replacement decision model (GRDM) is a mathematical model that computes the optimal sequence of replacement times for particular pieces of telecommunications network equipment. GRDM takes information about costs and revenues and their trends in time associated with existing and emerging technologies and services and calculates the sequence of technology replacement intervals that minimizes the net present worth of expenditures associated with embedded plant and its replacements. The generality of the model supports its application to a broad range of network evolution issues, including the deployment of fiber optics and intelligent network features. An illustrative application of GRDM is presented which evaluates how the optimal economic lives of analog and digital switching equipment change as the assumed date of widespread broadband switching availability is varied View full abstract»

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  • Robust design and planning of a worldwide intelligent network

    Page(s): 1219 - 1230
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    The authors describe the structure of the worldwide intelligent network (WIN), describe methods for its design and planning, investigate the adequacy of decentralized control for problem-free worldwide call completion, explore the feasibility of adaptive routing and control concepts, discuss network robustness/reliability objectives, and describe a strategy for achieving these objectives for all cooperating international carriers. Several decentralized adaptive routing policies that are particularly attractive in the WIN environment and network performance improvements that can be achieved with the introduction of flexible routing capabilities are characterized. It is shown by example that network integration coupled with flexible routing and bandwidth allocation for preferential treatment of new services provides an effective approach for robust and economical new service provisioning View full abstract»

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  • Computer-aided design procedures for survivable fiber optic networks

    Page(s): 1188 - 1197
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    The authors describe methods to design cost-effective survivable telecommunications networks that use fiber-optic transmission links. One of these methods utilizes optical switching devices to implement route diversity during cable cuts. These methods have been incorporated into a software tool consisting of three modules: a topology generator, a circuit to DS3 bundler, and a multiplex layout system. This tool is compact enough to run on a personal computer. Each of these three modules is described, and sample results are provided View full abstract»

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  • Topological analysis of packet networks

    Page(s): 1243 - 1252
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    The author describes a unified approach for the topological analysis of nonhierarchical and hierarchical packet networks. The approach differs from previous approaches in adopting an end-to-end mean delay objective and including a variety of practical routing constraints. These include limits on the number of paths allowed in a route, limits on the number of hops allowed in a path, and constraints due to prevalent virtual circuit implementations. For a broad range of networks, quantitative analysis based on this approach provides new insights into the complex relationships between network topology and routing and delay constraints. It is shown that the sole use of a network average delay criterion often leads to network designs that exhibit poor end-to-end mean delays for some node pairs, and that it is possible to configure networks that meet an end-to-end mean delay objective for every node pair at little or no additional cost View full abstract»

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  • All-digital network transmission planning and terminal requirements

    Page(s): 1166 - 1171
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    The development of a proposed transmission plan for an all-digital network is described. The main objectives of the plan are to obtain optimum end-to-end loudness grade-of-service, bit transparency, and echo control on all-digital connections and to ensure adequate transmission performance on hybrid connections, i.e. mixed analog/digital. These objectives are met by migrating connection loss, traditionally applied in the network, to the analog side of the digital/analog interface in the digital terminal. Thus the network transmission plan and digital access terminal characteristics are strongly interrelated. The proposed plan provides additional advantages including elimination of switched losses in the network when digital terminals are used and easy interconnection between networks (public and private) View full abstract»

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  • Fiberoptic circuit network design under reliability constraints

    Page(s): 1181 - 1187
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    A general mathematical model for a network design problem with reliability constraints and a revised formulation which seems particularly appropriate for fiber-optics networks is presented. Upper and lower bounding procedures based on continuous relaxations of this modified formulation are described. Preliminary computational results are reported. Limited computational results indicate a good performance of the algorithm, producing a gap between lower and upper bounds that is sufficiently small for a branch-and-bound procedure to be applicable View full abstract»

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  • Analysis and design of a highly reliable transport architecture for ISDN frame-relay networks

    Page(s): 1231 - 1242
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    The authors explore control strategies in the design of a high-performance transport architecture for integrated services digital network (ISDN) frame-relay networks. For real-time congestion control, buffer management, priority queueing, adaptive windowing, and selective frame, discard policies are described that can effectively maximize network efficiency while preventing unfair usage of shared network resources. Virtual-circuit routing strategies are proposed that ensure an efficient distribution of traffic loads across the network despite variations in traffic patterns and topology changes. It is shown that source routing provides significant performance benefits over link-by-link routing, particularly in large networks that are not so densely connected. Routing table update and call acceptance mechanisms are described that provide for efficient bandwidth management in the network. Fault-tolerant strategies are described that include fast failure detection and local reroute. These strategies are capable of restoring affected virtual circuits in less than 10 s, which is adequate for session maintenance under most application scenarios View full abstract»

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  • Performance analysis of cellular mobile communication systems with dynamic channel assignment

    Page(s): 1172 - 1180
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (880 KB)  

    The traffic analysis of small-cell mobile networks with dynamic channel assignment is investigated to determine their blocking performance, using a hybrid method of analysis and simulation. The authors particularly focus on the performance problems presented by networks with heterogeneous cell traffic loads, the impact of traffic volatility among the cells, and the impact of multichannel traffic on the channel blocking probabilities. Significant improvement in network performance with dynamic channel assignment is established by numerical results View full abstract»

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  • Structured systems analysis methodology for design of an ATM network architecture

    Page(s): 1263 - 1273
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1064 KB)  

    The asynchronous transfer mode (ATM) network design problem is treated as a resource-allocation problem. Traffic control is applied to different entities: packets, bursts, calls, and flows. Each of these entities can be controlled locally, within an exchange, or globally, at the network level. This gives rise to a multistrata architecture, where the resource-allocation stratum is defined both by the layer of traffic flow and the control level. Dedicated and virtual connections can be set up in all strata: for bursts, calls, subscriptions, and flows, at the exchange, subnetwork, and network levels. The open systems interconnection protocols are used to map heterogeneous user entities onto uniform network entities. The critical load is defined, which is where burst and call fluctuations begin to result in long queues and big packet delays. The critical load is used to determine thresholds, at the network and exchange level, for the number of virtual or dedicated connections which can be established in each traffic class View full abstract»

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Aims & Scope

IEEE Journal on Selected Areas in Communications focuses on all telecommunications, including telephone, telegraphy, facsimile, and point-to-point television, by electromagnetic propagation.

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Meet Our Editors

Editor-in-Chief
Muriel Médard
MIT