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Communications Magazine, IEEE

Issue 7 • Date July 2004

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Displaying Results 1 - 25 of 37
  • Load-adaptive inter-piconet scheduling in small-scale Bluetooth scatternets

    Page(s): 136 - 142
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (570 KB) |  | HTML iconHTML  

    Bluetooth enables wireless communication via ad hoc networks. The basic topology (piconet) is a collection of slaves controlled by a master. A scatternet is a multihop network of piconets. We anticipate that most scatternets will be composed of only a few piconets. However, even in small scatternets, efficient data flow requires the design of inter-piconet scheduling algorithms. Thus, this article presents and evaluates a load adaptive scheduling algorithm tailored for small-scale scatternets. The main advantage of this algorithm is the use of the Bluetooth low-power hold mode, which allows greater flexibility than other low-power modes. A simulation model has been developed in order to evaluate the performance of the algorithm. We show that the results obtained by the model are very close to the analytic results. Then we evaluate the performance of various intra-piconet scheduling algorithms. Finally, we present simulation results regarding inter-piconet scheduling, and compare the proposed algorithm to algorithms using the sniff mode. View full abstract»

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  • Experiences in the application of XML for device management

    Page(s): 92 - 100
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (719 KB) |  | HTML iconHTML  

    An explosion in the use of XML representation for data in both Web-based and traditional software applications and systems has had a profound impact on software architectures for both application and systems software. This development, coupled with the maturing of the XML standards and widespread support of XML libraries, utilities, and applications, is catalyzing changes in the design of data networking products and the software systems created to manage them. These changes are driven by the promised benefits of faster product development, tighter system integration and more robust device management. In this article, we describe our experiences in exploring and designing network management solutions for products ranging from small resource-limited data networking to high-capacity server-hosted control plane monitoring systems. We describe the motivations and explorations that led to the approach we finally adopted, and summarize what we have learned in the process. View full abstract»

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  • Resilience in GMPLS path management: model and mechanism

    Page(s): 128 - 135
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (621 KB) |  | HTML iconHTML  

    The recent advent of converging the IP and optical networks has necessitated the development of a generalized multiprotocol label switching framework. Resilience becomes more important than ever before in a GMPLS network since a single cut of an optical fiber may generate hundreds of link and node failures at high layers of the GMPLS architecture. In this article we briefly survey the current work regarding GMPLS recovery management, and present a new resilience-based dynamic GMPLS path management strategy. We present a simple model to represent the resilience requirements in GMPLS path management, and propose fast path management algorithms. The salient feature of the proposed approach is that it enables the paths to be dynamically selected under multiple simultaneous failure occurrences while satisfying the resilience requirement. Backup path design rules are developed, and the condition for backup path availability is derived for the special mesh-type GMPLS network. Finally, a simple example is shown to illustrate the effectiveness of the proposed resilience model and path management mechanism. View full abstract»

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  • Advertisers' index

    Page(s): 144
    Save to Project icon | Request Permissions | PDF file iconPDF (175 KB)  
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  • Radio Resource Management for Multimedia QoS Support in Wireless Networks - [Book Review]

    Page(s): 12 - 13
    Save to Project icon | Request Permissions | PDF file iconPDF (315 KB)  
    Freely Available from IEEE
  • Toward scalable admission control for VoIP networks

    Page(s): 42 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (505 KB) |  | HTML iconHTML  

    We present an overview of scalable admission control in IP networks. We introduce various approaches and discuss the mechanism and characteristics of each method. In particular, we argue that end-to-end measurement based admission control (EMBAC), which employs end-to-end on-demand probing, should be used for call admission control. Second, we consider use of EMBAC in VoIP networks. We present a new probability-based EMBAC scheme and show that its performance is close to the ideal method using virtual-trunk-based admission control. We also present a QoS allocation approach for selecting an admission threshold and dimensioning link capacities. A simple network design and evaluation results suggest that this QoS allocation approach is effective to adequately dimension a network, while satisfying end-to-end targets in terms of blocking probability and packet loss rate. View full abstract»

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  • Applying the Web ontology language to management information definitions

    Page(s): 68 - 74
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (563 KB) |  | HTML iconHTML  

    The extended markup language (XML) has emerged in the Internet world as a standard representation format, which can be useful to describe and transmit management information. However, XML formats alone do not give formal semantics to it. To solve this question, ontology languages based on the resource description framework can be used to improve the expressiveness of management information specifications. This article presents an approach that uses an XML-based ontology language to define network and system management information. For this, the structures of the Web ontology language known as OWL are analyzed and compared to those used in management definitions, also studying the advantages ontology languages can provide in this area. View full abstract»

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  • IEEE Communications Letters

    Page(s): 27
    Save to Project icon | Request Permissions | PDF file iconPDF (229 KB)  
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  • Implementing VoIP: a voice transmission performance progress report

    Page(s): 36 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (517 KB) |  | HTML iconHTML  

    Aiming to introduce voice over IP networks and services in ways that satisfy the voice quality expectations of our customers, we have been conducting laboratory studies of how VoIP transmission affects voice quality while also carefully monitoring and managing several field implementations of VoIP. This article summarizes much of what we have learned in this work, and we hope it provides a useful progress report on the industry's evolution to VoIP. We review our data on the voice quality effects of packet loss, delay, speech coders, packet loss concealment algorithms, and the compression option of suppressing transmission during silence. Because the familiar problem of echo has emerged repeatedly in the VoIP environment, we review this issue in some detail. Packet loss and delay variation measurements made on private VoIP networks are reviewed, and the data here are encouraging. We finish by making our case that the network planning tool known as the E-model is currently an inexact predictor of VoIP network performance. View full abstract»

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  • XML-based configuration management for IP network devices

    Page(s): 84 - 91
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (662 KB) |  | HTML iconHTML  

    As the Internet continues to grow, the tasks of operations and management of IP networks and systems are becoming more difficult. Over the past few years, much effort has been given to improve the deficiencies of SNMP, but most have failed to be standardized. One critical deficiency of SNMP is in the area of configuration management. Recent work focuses on the use of XML technology for network and service management as an alternative or complementary approach to SNMP. This article presents the IETF's latest effort, Netconf, which is viewed by many as a promising revolutionary solution for configuration management. To validate this new effort, we present the design and implementation of an XML-based configuration management system based on Netconf. We also discuss our experience with XCMS and make some suggestions for improving the current Netconf protocol. View full abstract»

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  • The state of the art in interplanetary Internet

    Page(s): 108 - 118
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (837 KB) |  | HTML iconHTML  

    Developments in space technologies are enabling the realization of deep space scientific missions such as Mars exploration. Interplanetary (IPN) Internet is expected to be the next step in the design and development of deep space networks as the Internet in the space. However, there are significant challenges to be addressed for the realization of this objective. This article captures the current state of the art and open research challenges, and intends to motivate researchers around the world to tackle these challenging problems and help realize the IPN Internet. View full abstract»

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  • On management technologies and the potential of Web services

    Page(s): 58 - 66
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (741 KB) |  | HTML iconHTML  

    From the early days of management research and standardization in the late 1980's, there has always been a quest for a management technology that would be general enough to be used for network, system, service, and distributed application management; efficient in terms of information retrieval time, computational resources required, and management traffic incurred; and easy to use in order to reduce development time and operational costs. From protocol-based approaches such as OSI management and SNMP, attention shifted to distributed object and Web-based approaches. Recently, XML-based approaches and, in particular, Web services have been emerging as a promising Internet-based technology that might also be used for management. In this article we survey first the key aspects of protocol and distributed object approaches to management. We subsequently examine Web services as a distributed object approach to management, and consider its suitability, usability, and performance in comparison to SNMP and CORBA. View full abstract»

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  • VoIP reliability: a service provider's perspective

    Page(s): 48 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (597 KB) |  | HTML iconHTML  

    Voice over IP services offer important revenue-generating opportunities, as well as many technical challenges in providing high-quality services. Users have come to expect highly available telecommunications services with high-quality voice. Service providers need reliable high-performance networks to meet user expectations, and must be able to guarantee performance and reliability to their customers. In converged voice and data networks, the network infrastructure must deliver very high quality and availability for some customer needs, while also providing low-cost high-capacity bandwidth for other needs. The use of quality of service mechanisms to provide prioritization for various traffic types is a key element needed for voice and data network convergence. However, it is not sufficient if the underlying networks are unreliable. The focus of this article is to address the reliability aspects of VoIP services, including the underlying IP networks. View full abstract»

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  • Integrating SNMP agents with XML-based management systems

    Page(s): 76 - 83
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (631 KB) |  | HTML iconHTML  

    XML-based network management systems are becoming more and more popular these days. However, it has to be taken into account that there is a broad existing management infrastructure based on non-XML protocols. Today, the most dominant technology in Internet management is based on the SNMP framework. This article presents an approach for seamless integration of management information supplied by SNMP agents into XML-based systems. This is done by an automated transformation of SMI MIB definitions into XML schema definitions, which implies a corresponding transformation of SNMP management information into XML documents. Furthermore, we present an SNMP-to-XML gateway that allows retrieval of such XML management information at runtime. View full abstract»

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  • Perceptual QoS assessment technologies for VoIP

    Page(s): 28 - 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (551 KB) |  | HTML iconHTML  

    Since quality is not generally guaranteed in an IP network, the proper design and management of networks and/or terminals for high-quality voice over IP services and maintenance of service levels is important. In terms of quality design and management, methodologies for appropriately and effectively evaluating the perceptual QoS of VoIP are indispensable. This article gives an overview of the state of the art of quality assessment technologies for VoIP, including recent work on improving their accuracy. View full abstract»

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  • GPRS: Gateway to Third-Generation Mobile Networks - [Book Review]

    Page(s): 12
    Save to Project icon | Request Permissions | PDF file iconPDF (229 KB)  
    Freely Available from IEEE
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  • Lightpaths on demand: a Web-services-based management system

    Page(s): 101 - 107
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (595 KB) |  | HTML iconHTML  

    User-controlled optical networks play a key role in supporting electronic transfer of the enormous volumes of data generated in emerging e-science experiments. The ability of users to manage their own resources enables provisioning of bandwidth-guaranteed tunnels on demand without the costs associated with conventional managed services offered by network providers. However, building high-performance user-controlled networks has only become feasible in the last few years, as trends in the telecommunications industry have made it possible for users to purchase installed optical fiber and light it using their own premises equipment. Consequently, suitable network management technologies have not yet evolved. In particular, there is presently no means for users to easily provision bandwidth-guaranteed tunnels across multiple independent management domains. In this article we present a user-controlled lightpath management system that addresses this problem. We begin by reviewing the high-level functionality of the system. Then we examine the software architecture. Finally, we discuss design challenges faced while building the system and propose future extensions. View full abstract»

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  • IEEE Communications Magazine

    Page(s): 0_1
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    Freely Available from IEEE

Aims & Scope

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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Editor-in-Chief
Sean Moore
Centripetal Networks