A concept of Differentiated Services architecture supporting military oriented Quality of Service, Journal of Telecommunications and Information Technology, 2003, nr 2

This paper presents a concept of IP Differentiated Services (DiffServ) architecture in conjunction with bandwidth brokerage and policy based network management, all aimed at efficient and flexible provision of the military oriented Quality of Service (M-QoS) features in the Australian Defence (strategic) wide area network and its satellite trunk interconnections with the tactical domain. Typical DiffServ functions are analysed in the paper with regard to their roles in offering M-QoS. Some preliminary simulation results of applying these mechanisms to achieve traffic policing and differentiation for (UDP) video traffic streams, are also presented. Finally, the paper proposes the use of bandwidth brokerage in each DiffServ domain to facilitate automatic Service Level Specification (SLS) arrangements with end-user applications, and policy based network management to support the flexible implementation of bandwidth brokerage

Journal of Telecommunications and Information Technology, 2003, nr 2

kwartalni

Interoperability of wireless communication technologies in hybrid networks: Evaluation of end-to-end interoperability issues and quality of service requirements

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Hybrid Networks employing wireless communication technologies have nowadays brought closer the vision of communication “anywhere, any time with anyone”. Such communication technologies consist of various standards, protocols, architectures, characteristics, models, devices, modulation and coding techniques. All these different technologies naturally may share some common characteristics, but there are also many important differences. New advances in these technologies are emerging very rapidly, with the advent of new models, characteristics, protocols and architectures. This rapid evolution imposes many challenges and issues to be addressed, and of particular importance are the interoperability issues of the following wireless technologies: Wireless Fidelity (Wi-Fi) IEEE802.11, Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16, Single Channel per Carrier (SCPC), Digital Video Broadcasting of Satellite (DVB-S/DVB-S2), and Digital Video Broadcasting Return Channel through Satellite (DVB-RCS). Due to the differences amongst wireless technologies, these technologies do not generally interoperate easily with each other because of various interoperability and Quality of Service (QoS) issues. The aim of this study is to assess and investigate end-to-end interoperability issues and QoS requirements, such as bandwidth, delays, jitter, latency, packet loss, throughput, TCP performance, UDP performance, unicast and multicast services and availability, on hybrid wireless communication networks (employing both satellite broadband and terrestrial wireless technologies). The thesis provides an introduction to wireless communication technologies followed by a review of previous research studies on Hybrid Networks (both satellite and terrestrial wireless technologies, particularly Wi-Fi, WiMAX, DVB-RCS, and SCPC). Previous studies have discussed Wi-Fi, WiMAX, DVB-RCS, SCPC and 3G technologies and their standards as well as their properties and characteristics, such as operating frequency, bandwidth, data rate, basic configuration, coverage, power, interference, social issues, security problems, physical and MAC layer design and development issues. Although some previous studies provide valuable contributions to this area of research, they are limited to link layer characteristics, TCP performance, delay, bandwidth, capacity, data rate, and throughput. None of the studies cover all aspects of end-to-end interoperability issues and QoS requirements; such as bandwidth, delay, jitter, latency, packet loss, link performance, TCP and UDP performance, unicast and multicast performance, at end-to-end level, on Hybrid wireless networks. Interoperability issues are discussed in detail and a comparison of the different technologies and protocols was done using appropriate testing tools, assessing various performance measures including: bandwidth, delay, jitter, latency, packet loss, throughput and availability testing. The standards, protocol suite/ models and architectures for Wi-Fi, WiMAX, DVB-RCS, SCPC, alongside with different platforms and applications, are discussed and compared. Using a robust approach, which includes a new testing methodology and a generic test plan, the testing was conducted using various realistic test scenarios on real networks, comprising variable numbers and types of nodes. The data, traces, packets, and files were captured from various live scenarios and sites. The test results were analysed in order to measure and compare the characteristics of wireless technologies, devices, protocols and applications. The motivation of this research is to study all the end-to-end interoperability issues and Quality of Service requirements for rapidly growing Hybrid Networks in a comprehensive and systematic way. The significance of this research is that it is based on a comprehensive and systematic investigation of issues and facts, instead of hypothetical ideas/scenarios or simulations, which informed the design of a test methodology for empirical data gathering by real network testing, suitable for the measurement of hybrid network single-link or end-to-end issues using proven test tools. This systematic investigation of the issues encompasses an extensive series of tests measuring delay, jitter, packet loss, bandwidth, throughput, availability, performance of audio and video session, multicast and unicast performance, and stress testing. This testing covers most common test scenarios in hybrid networks and gives recommendations in achieving good end-to-end interoperability and QoS in hybrid networks. Contributions of study include the identification of gaps in the research, a description of interoperability issues, a comparison of most common test tools, the development of a generic test plan, a new testing process and methodology, analysis and network design recommendations for end-to-end interoperability issues and QoS requirements. This covers the complete cycle of this research. It is found that UDP is more suitable for hybrid wireless network as compared to TCP, particularly for the demanding applications considered, since TCP presents significant problems for multimedia and live traffic which requires strict QoS requirements on delay, jitter, packet loss and bandwidth. The main bottleneck for satellite communication is the delay of approximately 600 to 680 ms due to the long distance factor (and the finite speed of light) when communicating over geostationary satellites. The delay and packet loss can be controlled using various methods, such as traffic classification, traffic prioritization, congestion control, buffer management, using delay compensator, protocol compensator, developing automatic request technique, flow scheduling, and bandwidth allocation

Structures and materials technology needs for communications and remote sensing spacecraft

This report documents trade studies conducted from the perspective of a small spacecraft developer to determine and quantify the structures and structural materials technology development needs for future commercial and NASA small spacecraft to be launched in the period 1999 to 2005. Emphasis is placed on small satellites weighing less than 1800 pounds for two focus low-Earth orbit missions: commercial communications and remote sensing. The focus missions are characterized in terms of orbit, spacecraft size, performance, and design drivers. Small spacecraft program personnel were interviewed to determine their technology needs, and the results are summarized. A systems-analysis approach for quantifying the benefits of inserting advanced state-of-the-art technologies into a current reference, state-of-the-practice small spacecraft design is developed and presented. This approach is employed in a set of abbreviated trade studies to quantify the payoffs of using a subset of 11 advanced technologies selected from the interview results The 11 technology development opportunities are then ranked based on their relative payoff. Based on the strong potential for significant benefits, recommendations are made to pursue development of 8 and the 11 technologies. Other important technology development areas identified are recommended for further study

Air Traffic Management Abbreviation Compendium

As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages. In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation

Journal of Telecommunications in Higher Education

In This Issue 6 Meeting Bandwidth Challenges on Campus 12 Voice-over-LAN: A Solution for Convergence in the Enterprise 20 Going Beyond Best Effort IP Networking 25 The Politics of Convergence 32 Pursuing the Promise of the Paperless Office 38 New Visions for University Cellular Service 44 Maintaining Excellence at UM

Journal of Telecommunications in Higher Education

In This Issue 6 Meeting Bandwidth Challenges on Campus 12 Voice-over-LAN: A Solution for Convergence in the Enterprise 20 Going Beyond Best Effort IP Networking 25 The Politics of Convergence 32 Pursuing the Promise of the Paperless Office 38 New Visions for University Cellular Service 44 Maintaining Excellence at UM

Strategic Latency Unleashed: The Role of Technology in a Revisionist Global Order and the Implications for Special Operations Forces

The article of record may be found at https://cgsr.llnl.govThis work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344. The views and opinions of the author expressed herein do not necessarily state or reflect those of the United States government or Lawrence Livermore National Security, LLC. ISBN-978-1-952565-07-6 LCCN-2021901137 LLNL-BOOK-818513 TID-59693This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344. The views and opinions of the author expressed herein do not necessarily state or reflect those of the United States government or Lawrence Livermore National Security, LLC. ISBN-978-1-952565-07-6 LCCN-2021901137 LLNL-BOOK-818513 TID-5969

Interoperability of wireless communication technologies in hybrid networks : evaluation of end-to-end interoperability issues and quality of service requirements

Hybrid Networks employing wireless communication technologies have nowadays brought closer the vision of communication “anywhere, any time with anyone”. Such communication technologies consist of various standards, protocols, architectures, characteristics, models, devices, modulation and coding techniques. All these different technologies naturally may share some common characteristics, but there are also many important differences. New advances in these technologies are emerging very rapidly, with the advent of new models, characteristics, protocols and architectures. This rapid evolution imposes many challenges and issues to be addressed, and of particular importance are the interoperability issues of the following wireless technologies: Wireless Fidelity (Wi-Fi) IEEE802.11, Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16, Single Channel per Carrier (SCPC), Digital Video Broadcasting of Satellite (DVB-S/DVB-S2), and Digital Video Broadcasting Return Channel through Satellite (DVB-RCS). Due to the differences amongst wireless technologies, these technologies do not generally interoperate easily with each other because of various interoperability and Quality of Service (QoS) issues. The aim of this study is to assess and investigate end-to-end interoperability issues and QoS requirements, such as bandwidth, delays, jitter, latency, packet loss, throughput, TCP performance, UDP performance, unicast and multicast services and availability, on hybrid wireless communication networks (employing both satellite broadband and terrestrial wireless technologies). The thesis provides an introduction to wireless communication technologies followed by a review of previous research studies on Hybrid Networks (both satellite and terrestrial wireless technologies, particularly Wi-Fi, WiMAX, DVB-RCS, and SCPC). Previous studies have discussed Wi-Fi, WiMAX, DVB-RCS, SCPC and 3G technologies and their standards as well as their properties and characteristics, such as operating frequency, bandwidth, data rate, basic configuration, coverage, power, interference, social issues, security problems, physical and MAC layer design and development issues. Although some previous studies provide valuable contributions to this area of research, they are limited to link layer characteristics, TCP performance, delay, bandwidth, capacity, data rate, and throughput. None of the studies cover all aspects of end-to-end interoperability issues and QoS requirements; such as bandwidth, delay, jitter, latency, packet loss, link performance, TCP and UDP performance, unicast and multicast performance, at end-to-end level, on Hybrid wireless networks. Interoperability issues are discussed in detail and a comparison of the different technologies and protocols was done using appropriate testing tools, assessing various performance measures including: bandwidth, delay, jitter, latency, packet loss, throughput and availability testing. The standards, protocol suite/ models and architectures for Wi-Fi, WiMAX, DVB-RCS, SCPC, alongside with different platforms and applications, are discussed and compared. Using a robust approach, which includes a new testing methodology and a generic test plan, the testing was conducted using various realistic test scenarios on real networks, comprising variable numbers and types of nodes. The data, traces, packets, and files were captured from various live scenarios and sites. The test results were analysed in order to measure and compare the characteristics of wireless technologies, devices, protocols and applications. The motivation of this research is to study all the end-to-end interoperability issues and Quality of Service requirements for rapidly growing Hybrid Networks in a comprehensive and systematic way. The significance of this research is that it is based on a comprehensive and systematic investigation of issues and facts, instead of hypothetical ideas/scenarios or simulations, which informed the design of a test methodology for empirical data gathering by real network testing, suitable for the measurement of hybrid network single-link or end-to-end issues using proven test tools. This systematic investigation of the issues encompasses an extensive series of tests measuring delay, jitter, packet loss, bandwidth, throughput, availability, performance of audio and video session, multicast and unicast performance, and stress testing. This testing covers most common test scenarios in hybrid networks and gives recommendations in achieving good end-to-end interoperability and QoS in hybrid networks. Contributions of study include the identification of gaps in the research, a description of interoperability issues, a comparison of most common test tools, the development of a generic test plan, a new testing process and methodology, analysis and network design recommendations for end-to-end interoperability issues and QoS requirements. This covers the complete cycle of this research. It is found that UDP is more suitable for hybrid wireless network as compared to TCP, particularly for the demanding applications considered, since TCP presents significant problems for multimedia and live traffic which requires strict QoS requirements on delay, jitter, packet loss and bandwidth. The main bottleneck for satellite communication is the delay of approximately 600 to 680 ms due to the long distance factor (and the finite speed of light) when communicating over geostationary satellites. The delay and packet loss can be controlled using various methods, such as traffic classification, traffic prioritization, congestion control, buffer management, using delay compensator, protocol compensator, developing automatic request technique, flow scheduling, and bandwidth allocation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Deep sea moorings fishbite handbook

The purpose of this handbook is to bring awareness and a degree of expertise to the very real problem of fish attacks on mooring lines and cables deployed in the open seas. Over the years the authors have carefully examined a large sample of damaged, sometimes entirely severed ropes retrieved from the sea. Often direct evidence and/or biological observations showed that the ropes were the victims of fish attacks. In many cases however the cause of rope failure remained difficult to ascertain. Techniques and rationales therefore had to be devised to elucidate the more thorny cases. Understanding a problem, the saying goes, is half of the solution. The other half, as far as this handbook is concerned, is of course to make known the ways which, at the moment, could help prevent fishbite attacks or at least abate its effects. Thus the handbook will follow a natural progression. A short introduction retraces the early suspicions which soon translated into confirmed fish attacks. The next two chapters cover the recognition and the extent of the fishbite problem in great depth. Chapter 2 presents in meticulous details the techniques which can be used to determine how a rope was damaged while in service, either by fishbite or any other plausible cause. The analysis of a data base which spans over twenty years and encompasses close to a thousand moorings is presented in Chapter 3: Dimensions of the fishbite problem. This chapter provides valuable information for use in estimating fishbite hazard. Who are the culprits and why they do it is reviewed in Chapter 4: Biting organisms and predisposing factors. This chapter identifies the marine organisms which have significant biting capabilities and outlines some of the environmental factors and processes which incite and result in fishbite damage. The last chapter: Prevention and control of fishbite damage, reviews the preventive methods used to reduce the incidence or the severity of fish attacks and the curative methods - including up to date techniques for jacketing metallic and non-metallic ropes and cables - which hopefully will protect mooring lines from the mechanical damage inflicted by fish teeth.Prepared for the Office of Naval Research under contract No. N00014-84-C-0134, N R 083-400