379 research outputs found

    Performance Comparison of Handover Rerouting Schemes in Wireless ATM Networks

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    The major issue of the integration of wireless and wired ATM is the support of user mobility. In effect, many technical challenges have been posed due to mobility support. One of the most important challenges is the rerouting of active connections of mobile user during handover. The rerouting of connections must exhibit low handover latency, limit the handover delay or disruption time, maintain efficient routes and minimise the impact on existing infrastructure. To date, two dominant approaches have been proposed to support mobility into fixed ATM network. The first is the mobility enhanced switches approach and the second is the separate network-elements specific to mobility approach. The first approach implies updating the existing ATM switches with mobile specific features. The mobility functions in the second approach are entrusted to a control station attached to the ATM switch as is implemented by the Magic WAND projects. In this thesis, we investigate how mobility can be supported using both approaches. To demonstrate the effectiveness of the above approaches, we compare the performance by analytically derived formulate for their hand over latency, hand over delay, buffer size, and bandwidth requirements. The formulate were derived for both backward and forward hand overs using a number of potential rerouting schemes proposed for wireless ATM network. The results show that the mobility enhanced switches approach has slightly better performance than the separate network elements approach. The results also show that backward handover has better performance than forward handover in terms of the handover delay and buffer requirement. Finally, the results show that the Anchor Switch rerouting scheme is the best among other rerouting schemes proposed for wireless ATM

    Satellite Networks: Architectures, Applications, and Technologies

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    Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled

    IP and ATM integration: A New paradigm in multi-service internetworking

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    ATM is a widespread technology adopted by many to support advanced data communication, in particular efficient Internet services provision. The expected challenges of multimedia communication together with the increasing massive utilization of IP-based applications urgently require redesign of networking solutions in terms of both new functionalities and enhanced performance. However, the networking context is affected by so many changes, and to some extent chaotic growth, that any approach based on a structured and complex top-down architecture is unlikely to be applicable. Instead, an approach based on finding out the best match between realistic service requirements and the pragmatic, intelligent use of technical opportunities made available by the product market seems more appropriate. By following this approach, innovations and improvements can be introduced at different times, not necessarily complying with each other according to a coherent overall design. With the aim of pursuing feasible innovations in the different networking aspects, we look at both IP and ATM internetworking in order to investigating a few of the most crucial topics/ issues related to the IP and ATM integration perspective. This research would also address various means of internetworking the Internet Protocol (IP) and Asynchronous Transfer Mode (ATM) with an objective of identifying the best possible means of delivering Quality of Service (QoS) requirements for multi-service applications, exploiting the meritorious features that IP and ATM have to offer. Although IP and ATM often have been viewed as competitors, their complementary strengths and limitations from a natural alliance that combines the best aspects of both the technologies. For instance, one limitation of ATM networks has been the relatively large gap between the speed of the network paths and the control operations needed to configure those data paths to meet changing user needs. IP\u27s greatest strength, on the other hand, is the inherent flexibility and its capacity to adapt rapidly to changing conditions. These complementary strengths and limitations make it natural to combine IP with ATM to obtain the best that each has to offer. Over time many models and architectures have evolved for IP/ATM internetworking and they have impacted the fundamental thinking in internetworking IP and ATM. These technologies, architectures, models and implementations will be reviewed in greater detail in addressing possible issues in integrating these architectures s in a multi-service, enterprise network. The objective being to make recommendations as to the best means of interworking the two in exploiting the salient features of one another to provide a faster, reliable, scalable, robust, QoS aware network in the most economical manner. How IP will be carried over ATM when a commercial worldwide ATM network is deployed is not addressed and the details of such a network still remain in a state of flux to specify anything concrete. Our research findings culminated with a strong recommendation that the best model to adopt, in light of the impending integrated service requirements of future multi-service environments, is an ATM core with IP at the edges to realize the best of both technologies in delivering QoS guarantees in a seamless manner to any node in the enterprise

    Virtual local area networking and its implementation at UNC-Chapel Hill

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    This study describes Virtual Local Area Network (VLAN) technologies, which allow a single, physical computer network to be divided into separate, logical networks, such that it appears to the end user that he or she is ona separate, physical network from users on other VLANs. VLAN technology can be used to imporve network performance while minimizing or eliminating problems encountered in large networks. VLANs can also enhance security and reduce the resources required to administer the network. This study combines descriptive research with a case study of the use of VLANs at the University of North Carolina at Chapel Hill. General networking and VLAN-specific concepts are synthesized from the literature, and the experience of UNC-CH's Academic Technology and Networks (ATN) department with their VLAN implementation is analyzed

    Wireless communications in the new millennium and third generation wireless networks

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    At the end of the 20 century, and at the beginning of this one, wireless communications are making large advances. The new technologies are on the way to provide a high-speed, high-quality information exchange between handheld terminals, and information repositories. The so called 2,5 generation networks, using the techniques like the HSCSD1, GPRS2, EDGE3, and the 3r generation wireless systems will help the wireless world to reach those goals. In this thesis I will start from the first and second-generation wireless networks, and then look into the 2,5 generation and 3rd generation wireless communications more in detail. The latest advances in the wireless world are the main focus of this paper although a short history of wireless communications is also given. The various aspects related to 3rd generation systems will be explored in this thesis, for example the air interface discussions, its time scale, its elements like the mobile equipment, software and security, USLM4, services that will be offered, etc. In addition, the technical factors and key technologies that are likely to shape the wireless network environment of the future will be explored. This part is expected to help us to see beyond the 3rd generation

    Campus Telecommunications Systems: Managing Change

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    The purpose of this book is to provide a broadbased understanding of the rapidly changing environment of campus telecommunications. The anticipated audience for this material is the non-technical university administrator who may not have direct responsibility for telecommunications, but has a need to understand the general environment in which his telecommunications manager functions and the basic concepts of the technology. Five topic areas were selected that best cover the preponderance of issues. No attempt has been made to associate or closely coordinate materials from one chapter\u27s subject to that of any other. Each chapter generally stands alone. In total, however, the five chapters address the topics and issues that most often generate inquiries from university administrators outside the telecommunications department. Introduction 1 The Changing Telecommunications Environment 2 Telecommunications Technology and the Campus 3 Student Services 4 Financing a New Telecommunications System . 5 Selecting a Consultant Glossary Inde

    Advanced Satellite Research Project: SCAR Research Database. Bibliographic analysis

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    The literature search was provided to locate and analyze the most recent literature that was relevant to the research. This was done by cross-relating books, articles, monographs, and journals that relate to the following topics: (1) Experimental Systems - Advanced Communications Technology Satellite (ACTS), and (2) Integrated System Digital Network (ISDN) and Advance Communication Techniques (ISDN and satellites, ISDN standards, broadband ISDN, flame relay and switching, computer networks and satellites, satellite orbits and technology, satellite transmission quality, and network configuration). Bibliographic essay on literature citations and articles reviewed during the literature search task is provided
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