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Communications Magazine, IEEE

Issue 8 • Date Aug. 1998

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Displaying Results 1 - 15 of 15
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  • Parallel simulation techniques for large-scale networks

    Page(s): 42 - 47
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    Simulation has always been an indispensable tool in the design and analysis of telecommunication networks. Due to performance limitations of the majority of simulators, usually network simulations have been done for rather small network models and for short timescales. In contrast, many difficult design problems facing today's network engineers concern the behavior of very large hierarchical multihop networks carrying millions of multiprotocol flows over long timescales. Examples include scalability and stability of routing protocols, packet losses in core routers, of long-lasting transient behavior due to observed self-similarity of traffic patterns. Simulation of such systems would greatly benefit from application of parallel computing technologies, especially now that multiprocessor workstations and servers have become commonly available. However, parallel simulation has not yet been widely embraced by the telecommunications community due to a number of difficulties. Based on our accumulated experience in parallel network simulation projects, we believe that parallel simulation technology has matured to the point that it is ready to be used in industrial practice of network simulation. This article highlights work in parallel simulations of networks and their promise View full abstract»

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  • Access network architectural issues for future telecommunication networks

    Page(s): 110 - 114
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    This article discusses the evolution of access networks to support future multimedia services, with emphasis on the role of Working Party 3 of ITU-T Study Group 13. An overview of the access network is given, and the interfaces between the access network and other portions of the telecommunications network such as the user-network interface (UNI), service node interface (SNI), and telecommunication management (Q3) interface are described. The major functions of the access network are summarized, and various examples of multimedia access architectures are discussed. Fundamental principles for the broadband service node interface (VB5) standard are reviewed View full abstract»

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  • SMAQ: a measurement-based tool for traffic modeling and queuing analysis. II. Network applications

    Page(s): 66 - 70, 75-7
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    For pt. I see ibid. p.56-65 (1998). SMAQ is a measurement-based tool for integration of traffic modeling and queuing analysis. It can be used in a variety of network design areas. For instance, it can be used as a traffic generator to generate various traces for network testing. It also provides numerical solutions of the queue length and loss rate performance for transport of multimedia traffic. Several application modules are built into the tool for the evaluation of statistical multiplexing, buffer dimensioning, and link bandwidth allocation. Other examples include the evaluation of traffic shaping, local-congestion control, and the modeling of wireless channel dynamics. As one will find, the SMAQ tool indeed provides a solution technique for network engineers to solve many of the current design issues View full abstract»

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  • Broadband traffic modeling: simple solutions to hard problems

    Page(s): 88 - 95
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    A much clearer picture of the progress toward an integrated high-speed multiservice network is now emerging. Such networks were anticipated over 20 years ago, at a time when packet switching was just another way to transmit data. Now the technology is so mature that media barons are organizing their investments in order to take advantage of its profitability. Many of the technical problems are now solved, and the fundamental protocols required for these networks are sufficiently well-defined to support a rapidly expanding industry. However, consensus on how to talk about the statistics of the data transmitted around these networks has not been readily forthcoming. Nevertheless, there now exists a family of models with sufficient richness to describe real traffic fairly well, which can be parameterized conveniently, and which degenerates to a readily analyzable Gaussian model in the situation of very large networks. This analysis leads to important architectural conclusions which accord with common sense, in particular the conclusion that integrated networks of the future should be able to provide better and better service with efficiency tending toward perfection. This is a rather happy conclusion which thoroughly confirms the current rapid drive toward an all-encompassing integrated multiservice network. Rather than the increase in traffic and diversity of service types leading to greater and greater complexity, it seems that the flow of traffic in our networks may become steadily more manageable View full abstract»

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  • An architecture for large scale Internet measurement

    Page(s): 48 - 54
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    Historically, the Internet has been woefully under-measured and under-instrumented. The problem is only getting worse with the network's ever-increasing size. We discuss the goals and requirements for building a “measurement infrastructure” for the Internet, in which a collection of measurement “platforms” cooperatively measure the properties of Internet paths and clouds by exchanging test traffic among themselves. The key emphasis of the architecture, which forms the underpinnings of the National Internet Measurement Infrastructure (NIMI) project, is on tackling problems related to scale. Consequently, the architecture emphasizes decentralized control of measurements; strong authentication and security; mechanisms for both maintaining tight administrative control over who can perform what measurements using which platforms, and delegation of some forms of measurement as a site's measurement policy permits; and simple configuration and maintenance of platforms View full abstract»

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  • TELPACK: an advanced teletraffic analysis package

    Page(s): 84 - 87
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    The performance evaluation of computer and communication networks gives rise to teletraffic problems of potentially large dimensionality. We summarize a unifying system theoretic approach to efficient solution of a diversity of such problems, and introduce TELPACK, a publicly available software that implements this approach View full abstract»

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  • Extending the effective bandwidth concept to networks with priority classes

    Page(s): 78 - 83
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    ATM switches are now being designed to allow connections to be partitioned into priority classes, with packets being emitted for higher priority classes before packets are emitted for lower priority classes. Accordingly, allocation of network resources based on different priority levels is becoming a realistic possibility. Thus, we need new methods for connection admission control and capacity planning that take account of the priority structure. We show that the notion of effective bandwidths can be used for these purposes when appropriately extended. The key is to have admissibility of a set of connections determined by a linear constraint for each priority level, involving a performance criterion for each priority level. For this purpose, connections are assigned more than one effective bandwidth, one for its own priority level and one for each lower priority level. Candidate effective bandwidths for each priority level can be determined by using previous methods associated with the first-in first-out discipline. The proposed effective bandwidth structure makes it possible to apply product-form stochastic loss network models to perform dimensioning View full abstract»

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  • SMAQ: a measurement-based tool for traffic modeling and queuing analysis. I. Design methodologies and software architecture

    Page(s): 56 - 65
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    SMAQ is a measurement-based tool for integration of traffic modeling and queuing analysis. There are three basic components in SMAQ. In the design of the first component, statistic measurement, the most critical issues are to identify the important traffic statistics for queuing analysis in a finite buffer system and then to build a measurement structure to collect them. Our study indicates that both first- and second-order traffic statistics, measured within a given frequency-window, have a very significant impact on the queue length and loss rate performance. In the design of the second component, matched modeling, the focal point is to construct a stochastic model that can match a wide range of important statistics collected in various applications. New methodologies and fast algorithms are developed for such construction on the basis of a circulant modulated Poisson process (CMPP). For the third component, queuing solutions, the basic requirement is to provide numerical solutions of the queue length and loss rate for transport of given traffic in a finite buffer system. A fast and stable computation method, called a Folding algorithm, is applied to provide both steady-state and transient solutions of various kinds, including congestion control performance where arriving traffic are selectively discarded based on queue thresholds. We provide both design methodologies and software architectures of these three components, with discussion of practical engineering issues for the use of the SMAQ tool View full abstract»

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  • Service quality in TINA: quality of service trading in open network architecture

    Page(s): 122 - 130
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    Enterprise-level QoS issues are discussed, from which QoS evolution paths are derived. Service-level QoS issues are identified, and they have been studied as a part of service quality issues in TINA service architecture. TINA stream binding and its role in the TINA QoS framework are presented. Soft guarantee of stream quality is proposed, which does not require strict resource reservation. The soft guarantee concept combined with TINA stream binding architecture supports progressive evolution of service quality View full abstract»

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  • Network evolution in the context of the global information infrastructure

    Page(s): 98 - 102
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    This article describes network evolution in the context of the global information infrastructure (GII), taking into consideration social and regulatory environments. It provides a GIIs vision for the evolution of wireless networks, which relies on the intelligent network (IN) to support the global and seamless introduction of services. It examines issues related to the Internet (e.g., resources, QoS, and security), which must be addressed properly before the Internet can be considered as the paradigm for the GII. In addition, this article discusses the software aspect of network evolution, equally applicable to all network paradigms. It focuses on the emergence of full network operating systems, which should transform networks into integrated programmable platforms supporting the development and execution of a wide range of services. Finally, this article suggests cooperation in standards definition among all players to effectively answer the technological challenges of future networks and provide both fair competition and regulated liberalization. The standardization of emerging network capabilities encompassing broadband, wireless/mobility, the Internet, and ultimately the GII, is presently ongoing in the ITU-T Study Group (SG) 13, the lead study group on the GII, and other standards organizations View full abstract»

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  • Applications of ATM in global networks

    Page(s): 104 - 109
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    This article describes the market drivers, objectives, and consequences of introducing ATM into public and private networks. To serve the diverse needs of environments and applications, ATM presents a broad choice of characteristics to users and providers. To harness this diversity and bring structure to the choices, this article discusses ATM transfer capabilities (ATCs) and quality of service (QoS) classes as specified in ITU-T Study Group 13. Industry aims to achieve consistency between the ITU-T and ATM Forum specifications. This article includes consideration of AALs and interworking in developing network strategies. Providers will offer a selection of the possible services defined for ATM. Also, each provider will communicate their strategy for preferred network utilization and efficient traffic through incentives to users View full abstract»

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  • Performance standards for the GII

    Page(s): 116 - 121
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    This article summarizes the traditional process for developing international telecommunication performance standards and describes enhancements that will be needed to adapt the process for use in the emerging global information infrastructure (GII). The necessary enhancements are being developed under the auspices of ITU-T Study Group 13 View full abstract»

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  • Simulation of rare events in communications networks

    Page(s): 36 - 41
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    Computer simulation is an important tool in the analysis and design of communications networks. In spite of the advances in computational power, using simulation to obtain rare event probabilities such as cell/packet loss or delay in networks still requires prohibitively long execution times. We provide an overview of importance sampling techniques and how they can be used to provide orders of magnitude speedup for many network problems View full abstract»

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IEEE Communications Magazine covers all areas of communications such as lightwave telecommunications, high-speed data communications, personal communications systems (PCS), ISDN, and more.

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Osman Gebizlioglu
Huawei Technologies