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1

Tsietsi, Mosiuoa Jeremia. "Prototyping a peer-to-peer session initiation protocol user agent." Thesis, Rhodes University, 2008. http://hdl.handle.net/10962/d1006603.

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The Session Initiation Protocol (SIP) has in recent years become a popular protocol for the exchange of text, voice and video over IP networks. This thesis proposes the use of a class of structured peer to peer protocols - commonly known as Distributed Hash Tables (DHTs) - to provide a SIP overlay with services such as end-point location management and message relay, in the absence of traditional, centralised resources such as SIP proxies and registrars. A peer-to-peer layer named OverCord, which allows the interaction with any specific DHT protocol via the use of appropriate plug-ins, was designed, implemented and tested. This layer was then incorporated into a SIP user agent distributed by NIST (National Institute of Standards and Technology, USA). The modified user agent is capable of reliably establishing text, audio and video communication with similarly modified agents (peers) as well as conventional, centralized SIP overlays.
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2

Mascarenhas, da Veiga Alves Manoel Eduardo. "Characterisation of end-to-end performance for web-based file server respositories." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09ENS/09ensm395.pdf.

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Bibliography: leaves 128-135. Investigates the behaviour of TCP bulk file transfer application sessions in a broadband access environment. Introduces some concepts for evaluating network behaviour: a path instability parameter for analyzing different TCP connections; a minimum RTT delay and a minimum typical path for estimating path characteristics between a client and application servers.
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3

Tsai, Shang-Yuan. "Device profiling analysis in Device-Aware Network." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FTsai.pdf.

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Thesis (M.S. in Systems Engineering)--Naval Postgraduate School, December 2004.
Thesis advisor(s): Singh Gurminder, John Gibson. Includes bibliographical references (p. 65-66). Also available online.
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4

Foulkes, Philip James. "An investigation into the control of audio streaming across networks having diverse quality of service mechanisms." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1004865.

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The transmission of realtime audio data across digital networks is subject to strict quality of service requirements. These networks need to be able to guarantee network resources (e.g., bandwidth), ensure timely and deterministic data delivery, and provide time synchronisation mechanisms to ensure successful transmission of this data. Two open standards-based networking technologies, namely IEEE 1394 and the recently standardised Ethernet AVB, provide distinct methods for achieving these goals. Audio devices that are compatible with IEEE 1394 networks exist, and audio devices that are compatible with Ethernet AVB networks are starting to come onto the market. There is a need for mechanisms to provide compatibility between the audio devices that reside on these disparate networks such that existing IEEE 1394 audio devices are able to communicate with Ethernet AVB audio devices, and vice versa. The audio devices that reside on these networks may be remotely controlled by a diverse set of incompatible command and control protocols. It is desirable to have a common network-neutral method of control over the various parameters of the devices that reside on these networks. As part of this study, two Ethernet AVB systems were developed. One system acts as an Ethernet AVB audio endpoint device and another system acts as an audio gateway between IEEE 1394 and Ethernet AVB networks. These systems, along with existing IEEE 1394 audio devices, were used to demonstrate the ability to transfer audio data between the networking technologies. Each of the devices is remotely controllable via a network neutral command and control protocol, XFN. The IEEE 1394 and Ethernet AVB devices are used to demonstrate the use of the XFN protocol to allow for network neutral connection management to take place between IEEE 1394 and Ethernet AVB networks. User control over these diverse devices is achieved via the use of a graphical patchbay application, which aims to provide a consistent user interface to a diverse range of devices.
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Hachfi, Fakhreddine Mohamed. "Future of asynchronous transfer mode networking." CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2639.

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The growth of Asynchronous Transfer Mode (ATM) was considered to be the ideal carrier of the high bandwidth applications like video on demand and multimedia e-learning. ATM emerged commercially in the beginning of the 1990's. It was designed to provide a different quality of service at a speed up 100 Gbps for both real time and non real time application. The turn of the 90's saw a variety of technologies being developed. This project analyzes these technologies, compares them to the Asynchronous Transfer Mode and assesses the future of ATM.
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6

Cavalaris, James George 1975. "Optimizing the data transmission protocols for remote interactive microscopy." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50424.

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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.
Includes bibliographical references (leaves 57-59).
by James George Cavalaris.
S.B.and M.Eng.
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7

Wickman, Tomas. "Evaluation of communication protocols between vehicle and server : Evaluation of data transmission overhead by communication protocols." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189228.

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This thesis project has studied a number of protocols that could be used to communicate between a vehicle and a remote server in the context of Scania’s connected services. While there are many factors that are of interest to Scania (such as response time, transmission speed, and amount of data overhead for each message), this thesis will evaluate each protocol in terms of how much data overhead is introduced and how packet loss affects this overhead. The thesis begins by giving an overview of how a number of alternative protocols work and what they offer with regards to Scania’s needs. Next these protocols are compared based on previous studies and each protocol’s specifications to determine which protocol would be the best choice for realizing Scania’s connected services. Finally, a test framework was set up using a virtual environment to simulate different networking conditions. Each of the candidate protocols were deployed in this environment and setup to send sample data. The behaviour of each protocol during these tests served as the basis for the analysis of all of these protocols. The thesis draws the conclusion that to reduce the data transmission overhead between vehicles and Scania’s servers the most suitable protocol is the UDP based MQTT SN.
I den här rapporten har jag undersökt ett antal protokoll som kan användas för att kommunicera mellan server och lastbil och därmed användas för Scanias Connected Services. Då det är många faktorer som är intressanta när det kommer till kommunikation mellan lastbil och server för Scania som till exempel responstid, överföringshastighet och mängden extra data vid överföring så har jag valt att begränsa mig till att utvärdera protokollen utifrån hur mycket extra data de använder vid överföring och hur detta påverkas av paketförlust. Rapporten börjar med att ge en överblick över vilka tänkbara protokoll som kan användas och vad de kan erbjuda gällande Scanias behov. Efter det så jämförs protokollen baserat på tidigare studier och protokollens specifikationer för att avgöra vilket protokoll som är bäst lämpat att användas i Scanias Connected Services. Sists så skapas ett virtuellt ramverk för att simulera olike nätverksförhållanden. Här testas varje protokoll och får sända olike datamängder för att sedan få sin prestanda utvärderad baserat på hur mycket extra data som sändes. Dessa resultat ligger sedan till grund för den analys och slutsats angående vilket protokoll som är bäst lämpat att användas av Scania. Rapporten drar slutsatsen att baserat på den information som finns tillgänglig och de resultat som ficks av testerna så skulle den UDP baserade MQTT-SN vara bäst lämpad för att minimera mängden extra data som skickas.
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8

Skelley, Daniel S., and Sidney R. Jr Jones. "THE IMPACT OF NETWORK ARCHITECTURE ON DATA ACQUISITION SYSTEMS." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609670.

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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California
The purpose of this paper is to present a broad view of the impact of network architectures on future data acquisition systems. The major advantages and challenges associated with the use of network architectures are rooted in the packetized structure of the data. Many of the issues raised are subtle and complex. It is not the intent of this paper to give these issues the thorough academic and technical analysis they deserve. It is the hope of the authors this paper will generate awareness and discussion on these issues.
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Yuan, Xiaochun, and 袁小春. "Routing protocols in all-optical packet switched networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31243885.

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Yuan, Xiaochun. "Routing protocols in all-optical packet switched networks /." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25100725.

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11

Bert, Denis. "Systemes d'annuaire osi : specifications de mise en oeuvre pour la messagerie et l'administration de reseau." Paris 6, 1988. http://www.theses.fr/1988PA066075.

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Etude et specification de l'utilisation des systemes d'annuaire pour l'adressage des systemes osi, l'administration de reseau et la messagerie electronique. Les modeles, services et protocoles des systemes d'annuaire osi definis par la nouvelle serie de recommandations ccitt x500 sont exposes. Sont ensuite decrits les mecanismes de consultation annuaire permettant, a partir d'un nom d'application ou d'une adresse reseau, de determiner les elements d'adressage application ou les informations de routage reseau
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12

Chen, Yan. "Traitement transactionnel dans un environnement OSI." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376126461.

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13

Kheirkhah, Sabetghadam Morteza. "MMPTCP : a novel transport protocol for data centre networks." Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/61781/.

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Modern data centres provide large aggregate capacity in the backbone of networks so that servers can theoretically communicate with each other at their maximum rates. However, the Transport Control Protocol (TCP) cannot efficiently use this large capacity even if Equal-Cost Multi-Path (ECMP) routing is enabled to exploit the existence of parallel paths. MultiPath TCP (MPTCP) can effectively use the network resources of such topologies by performing fast distributed load balancing. MPTCP is an appealing technique for data centres that are very dynamic in nature. However, it is ill-suited for handling short flows since it increases their flow completion time. To mitigate these problems, we propose Maximum MultiPath TCP (MMPTCP), a novel transport protocol for modern data centres. Unlike MPTCP, it provides high performance for all network flows. It also decreases the bursty nature of data centres, which is essentially rooted in traffic patterns of short flows. MMPTCP achieves these nice features by randomising a flow's packets via all parallel paths to a destination during the initial phase of data transmission until a certain amount of data is delivered. It then switches to MPTCP with several subflows in which data transmission is governed by MPTCP congestion control. In this way, short flows are delivered very fast via the initial phase only, and long flows are delivered by MPTCP with several subflows. We evaluate MMPTCP in a FatTree topology under various network conditions. We found that MMPTCP decreases the loss rate of all the links throughout the network and helps competing flows to achieve a better performance. Unlike MPTCP with a fixed number of subflows, MMPTCP offers high burst tolerance and low-latency for short flows while it maintains high overall network utilisation. MMPTCP is incrementally deployable in existing data centres because it does not require any modification to the network and application layers.
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Bale, Siddalingaswamy. "Simulation of data link layer of communication protocols using Ada." Virtual Press, 1989. http://liblink.bsu.edu/uhtbin/catkey/722787.

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Communication and networking are vast areas which are developing rapidly. It is very important to know in detail how the system works, how it can be enhanced to meet today's requirement, how to implement the appropriate techniques to obtain desired results etc. To explain all of the above, simulation techniques were adopted. Simulation plays an important role in developming new designs and modifying existing systems to make them more feasible and efficient.Protocols are the back bones of the communication systems and play a major role in data transfer. The review of literature provides an explanation of ISO/OSI models, layered approach and concepts of simulation. The simulation was carried out to explain the concepts of error detection, error correction and flow control in Data Link layer. Ada was used to develop the software, because of its concurrent processing tools called tasks. Also state-of-the-art utilities like Vax/Vms Screen Management System, File Definition Language, and Debugger were us ed in the program development.
Department of Computer Science
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15

Azizi, Davood. "OSIDEM : a demonstration of the transmission of open systems interconnection high level protocols." Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334035.

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16

Lim, Kok Seng. "Analysis of network management protocols in optical networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FLim%5FK.pdf.

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17

Vesilo, Rein Andres. "Issues in software engineering for implementing a multimedia document communication system using international standards." Thesis, The University of Sydney, 1989. https://hdl.handle.net/2123/26384.

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Multimedia documents are extensions of electronic documents, integrating text with other information types such as raster graphics images, geometric graphics images and audio. This thesis presents software strategies and techniques for implementing systems for processing and transferring multimedia documents based on international standards. The particular standards used are the ISO Office Document Architecture and Office Document Interchange Format (ODA/ODIF) standards and the ISO Open Systems Interconnection (OSI) standards. The three main areas of work are on the implementation of a multimedia document processing system, the development of software techniques for converting multimedia documents into ODA/ODIF and the development of strategies for implementing general 081 layers. A review of recent multimedia work is given. Two types of characteristics are examined: general characteristics of multimedia systems, which distinguishes them from other systems, and characteristics which distinguish different types of services provided by multimedia systems. A useful classification was found to be between highly multi-functional systems and single paradigm systems. The review also examines functional requirements of systems and recent trends in multimedia systems including use of tools and object-oriented approaches. The multimedia document system implemented is based on an IBM/PC compatible computer and uses the TEX document processing system as a basis for defining multimedia documents. Additional content types supported are images, structured voice, unstructured voice and limited graphics. Multimedia documents occur in three representations: logical form documents as multimedia TEX documents, formatted documents as multimedia DVI documents and interchange format documents as ODA/ODIF documents. System facilities include those to create, format, present and transfer documents. An important component of work on this system was the development of techniques to integrate the different media types and new system components with existing system components. These include standard command formats, file formats, generic interfaces, modular system design, shareable modules, reusable software and application of object oriented concepts. Software strategies for developing document translators to and from ODA/ODIF are discussed, using the multimedia TEX/DVI document as a particular case of local document representation. Document conversion is viewed as a process which preserves document semantics while converting document syntax. Software engineering issues involved in the design of document translators are examined. These include the use of interpreters and intermediate data structures, binding-time considerations, object oriented approaches, software reuse and software sharing. Specific ODA related considerations which affect the faithfulness of the document conversion process are discussed. These include structure conversion, content architecture conversion, tree handling, font handling, dimension conversion, coordinate system translation and positioning. Two document translators were implemented, one for encoding and one for decoding. Both use a four layer program structure which promotes generic handling of content types and modularity. The design of common modules used by both translators as well as other multimedia system programs are described, including an ASN.1 coding module (two versions), Computer Graphics Metafile (CGM) module, font modules, buffer module and file module. The work on 081, begun as part of the multimedia system, became a separate work area on the development of strategies for implementing a. general 081 layer. A key result was the development of a layer model consisting of six sublayers which extended existing layer models by including specific and generic sublayers in both the upper and lower layer interfaces. Finite state machine descriptions were developed to describe module functionality within the layer model. Strategies for realisation of the model included the development of a Pseudo Multitasking Operating System (PMOS) within which layer model components could be realised. Additional resource manager, timer, upper layer interface manager and lower laver interface manager modules were added to complete the layer functionality. To realise sublayer modules a program template and three-layer model were developed. Implementation of an 081 Session service using the layer model is described.
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Tan, Xu. "Protocols for wide band satellite systems with a large number of small voice and data users." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26745.

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Multiaccess protocols for integrated voice and data transmissions over satellite channels are studied, based on the SENET(slotted envelope network) structure. The satellite system is characterized as a wide band system with a large number of geographically distributed small voice and data users. Performance evaluations of commonly used protocols, i.e., ALOHA and reservation protocols, are first conducted, both analytically and by simulations. The effect of different voice backgrounds on data access protocols are shown explicitly. Based on these results, a control algorithm is proposed. Analyses and simulations show that ALOHA protocol incorporated with such a control mechanism is globally stable under the integrated environment; moreover, the performance deterioration due to voice backgrounds is dramatically reduced. The actual implementation aspects of the control algorithm are considered. An extension of the above results leads to a combined random/reservation protocol. Simulation and analysis results show that the combined protocol exhibits desired low delay and high throughput performance characteristics, with satisfactory voice blocking probability, under the worst user population assumption, i.e., all the voice sources and data sources are independent of each other — reflecting the nature of small earth station environment. The absence of the need for mini-slot structure lends ease and simplicity to the implementation of the combined protocol.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Zheng, Jun, and 鄭軍. "Performance analysis and algorithm design for data-driven IP/ATM labelswitching systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3124273X.

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Zheng, Jun. "Performance analysis and algorithm design for data-driven IP/ATM label switching systems." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22370584.

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Hernandez, Edwin A. "Adaptive networking protocol for rapid mobile environments." [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1001150.

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22

Uslu, Berk. "Development of Protocols and Methods for Predicting the Remaining Economic Life of Wastewater Pipe Infrastructure Assets." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/89668.

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Performance prediction modeling is a crucial step in assessing the remaining service life of pipelines. Sound infrastructure deterioration models are essential for accurately predicting future performance that, in turn, are critical tools for efficient maintenance, repair and rehabilitation decision making. The objective of this research is to develop a gravity and force main pipe performance deterioration model for predicting the remaining economic life of wastewater pipe for infrastructure asset management. For condition assessment of gravity pipes, the defect indices currently in practice, use CCTV inspection and a defect coding scale to assess the internal condition of the wastewater pipes. Unfortunately, in practice, the distress indices are unable to capture all the deterioration mechanisms and distresses on pipes to provide a comprehensive and accurate evaluation of the pipe performance. Force main pipes present a particular challenge in performance prediction modeling. The consequence of failure can be higher for the force mains relative to the gravity pipes which increases the risk associated with these assets. However, unlike gravity pipes, there are no industry standards for inspection and condition assessment for force mains. Furthermore, accessibility issues for inspections add to this challenge. Under Water Environmental and Reuse Foundation (WEandRF)'s Strategic Asset Management (SAM) Challenge, there was a planned three-phase development of this performance prediction model. Only Phases 1 and 2 were completed for gravity pipes under the SAM Challenge. Currently, 37 utilities nationally distributed have provided data and support for this research. Data standards are developed to capture the physical, operational, structural, environmental, financial, and other factors affecting the performance. These data standards were reviewed by various participating utilities and service providers for completeness and accuracy. The performance of the gravity and force main pipes are assessed with incorporating the single and combined effects of these parameters on performance. These indices assess the performance regarding; integrity, corrosion, surface wear, joint, lining, blockage, IandI, root intrusion, and capacity. These performance indices are used for the long-term prediction of performance. However, due to limitations in historical performance data, an advanced integrated method for probabilistic performance modeling to construct workable transition probabilities for predicting long-term performance has been developed. A selection process within this method chooses a suitable prediction model for a given situation in terms of available historical data. Prediction models using time and state-dependent data were developed for this prediction model for reliable long-term performance prediction. Reliability of performance assessments and long-term predictions are tested with the developed verification and validation (VeandVa) framework. VeandVa framework incorporates piloting the performance index and prediction models with artificial, field, and forensic data collected from participating utilities. The deterioration model and the supporting data was integrated with the PIPEiD (Pipeline Infrastructure Database) for effective dissemination and outreach.
PHD
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Scott, Terry A. "An implementation of the Kermit protocol using the Edison system." Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9878.

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24

Suryadevara, Usha. "Buffer management in tone allocated multiple access protocol." [Gainesville, Fla.] : University of Florida, 2001. http://purl.fcla.edu/fcla/etd/UFE0000357.

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Thesis (M.S.)--University of Florida, 2001.
Title from title page of source document. Document formatted into pages; contains vi, 78 p.; also contains graphics. Includes vita. Includes bibliographical references.
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Robinson, James Beresford. "Lntp : the implementation and performance of a new local area network transport protocol." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26523.

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In the past it has been convenient to adopt existing long haul network (LHN) protocols for use in local area networks (LANs). However, due to the different operating parameters that exist between these two types of networks, it is not possible for a LHN protocol to fully exploit the characteristics of a LAN. Thus, the need arises for a protocol designed specifically for use in a LAN environment. LNTP is one such transport level protocol. It was designed for exclusive use in LANs, and thus does not incorporate those features which are not relevant to a LAN environment. The result of this is a simpler and more efficient protocol. As well, LNTP employs a novel deferred flow control strategy which minimizes the time that a transmitting process will be blocked. This thesis examines the implementation of LNTP in the 4.2 BSD UNIX operating system. Various measurements are taken, and LNTP's performance is compared to that of TCP/IP, a LHN protocol which is often used in LAN environments. Several formulas are developed to determine the optimum values for various LNTP parameters, and these theoretical results are compared to the experimentally observed values. We conclude that LNTP does indeed outperform TCP/IP. However, due to the overhead of the non-LNTP specific protocol layers, this improvement is not as great as it might be. Nonetheless, LNTP proves itself to be a viable replacement for TCP/IP.
Science, Faculty of
Computer Science, Department of
Graduate
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26

Martinez, Lindolfo, and Larry Muzny. "NASA/LOCKHEED MARTIN-CSOC GROUND NETWORK AND SPACE NETWORK INTEROPERABILITY TESTBED." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605584.

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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
NASA and Lockheed Martin-CSOC have been supporting in the development of plans for the evolution of NASA’s Ground Network (GN) and Space Network (SN), and where possible, synchronizing those plans with plans for the evolution of the Deep Space Network (DSN). This paper describes a recommendation for a common ground system communication architecture based on the Consultative Committee for Space Data Systems (CCSDS) Space Link Extension (SLE).
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Matsson, Erik, Gustav Dahllöf, and Julius Nilsson. "Business to Business - Electronic Invoice Processing : A report on the challenges, solutions and outcomes for companies switching from manual to electronic invoice handling." Thesis, Högskolan i Jönköping, Internationella Handelshögskolan, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-26793.

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Electronic document handling was first used in the automotive industry in the early 1970’s, the way of communicating electronic at the time was concerned with the communication way of EDI (Hsieh, 2004). In the beginning of 2000 a new way of communicating electronic documents was introduced with the emergence of VAN-operators (Hsieh, 2004). This technology of communicating electronic invoices has shown to be less complex for the businesses than the previous EDI connections. The VAN-operators enable companies regardless of size, ERP, also known as Enterprise Resource Planning, system, formats or transaction volume to send and receive electronic invoices. The subject of electronic invoice handling have become increasingly debated, mainly because of the legislations taking place all over Europe, and as well as the environmental impact by business transactions being sent by paper. The objective of this thesis is to examine the challenges, solutions and outcomes for companies switching to electronic invoice handling. The data collected for the thesis is divided into two parts. The first part consist of information retrieved by previous literature as well as internet sources. The second part concerns the case studies conducted for the thesis in respect to our research questions. For this reason Scandinavian companies have been interviewed, with different precondition as in size, industry, transaction volume and IT structure. The findings from the first and second part have been analyzed and conclusion have been made, we suggest using a VAN-operators, which have shown to be the most appropriate alternative for companies that are implementing electronic invoice handling. The result of this thesis can be used as a guideline for companies when considering a switch from manual to electronic invoice handling.
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Bhattacharya, Sumit. "A Real-Time Bi-Directional Global Positioning System Data Link Over Internet Protocol." Ohio University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1121355433.

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Igumbor, Osedum Peter. "An investigation of protocol command translation as a means to enable interoperability between networked audio devices." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011128.

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Digital audio networks allow multiple channels of audio to be streamed between devices. This eliminates the need for many different cables to route audio between devices. An added advantage of digital audio networks is the ability to configure and control the networked devices from a common control point. Common control of networked devices enables a sound engineer to establish and destroy audio stream connections between networked devices that are distances apart. On a digital audio network, an audio transport technology enables the exchange of data streams. Typically, an audio transport technology is capable of transporting both control messages and audio data streams. There exist a number of audio transport technologies. Some of these technologies implement data transport by exchanging OSI/ISO layer 2 data frames, while others transport data within OSI/ISO layer 3 packets. There are some approaches to achieving interoperability between devices that utilize different audio transport technologies. A digital audio device typically implements an audio control protocol, which enables it process configuration and control messages from a remote controller. An audio control protocol also defines the structure of the messages that are exchanged between compliant devices. There are currently a wide range of audio control protocols. Some audio control protocols utilize layer 3 audio transport technology, while others utilize layer 2 audio transport technology. An audio device can only communicate with other devices that implement the same control protocol, irrespective of a common transport technology that connects the devices. The existence of different audio control protocols among devices on a network results in a situation where the devices are unable to communicate with each other. Furthermore, a single control application is unable to establish or destroy audio stream connections between the networked devices, since they implement different control protocols. When an audio engineer is designing an audio network installation, this interoperability challenge restricts the choice of devices that can be included. Even when audio transport interoperability has been achieved, common control of the devices remains a challenge. This research investigates protocol command translation as a means to enable interoperability between networked audio devices that implement different audio control protocols. It proposes the use of a command translator that is capable of receiving messages conforming to one protocol from any of the networked devices, translating the received message to conform to a different control protocol, then transmitting the translated message to the intended target which understands the translated protocol message. In so doing, the command translator enables common control of the networked devices, since a control application is able to configure and control devices that conform to different protocols by utilizing the command translator to perform appropriate protocol translation.
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Biswas, Kamanashis. "Energy Efficient Secure Routing in Wireless Sensor Networks." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/365658.

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Wireless Sensor Networks (WSNs) can contain thousands of small, inexpensive sensors that are randomly deployed in open and harsh environments to collect data. The short lifespan of the battery-operated sensors and the hostile environments necessitate the development of energy ecient and secure protocols in sensor networks. Among the wide variety of network protocols, routing plays the most signicant role in energy consumption since 70% of the total energy is consumed for data transmission in WSNs. Therefore, it is necessary to design energy ecient routing schemes to conserve energy and prolong the network lifetime. However, resource limited sensors, lack of a global addressing scheme, and application-specic design of WSNs make routing a challenge. Furthermore, security is another critical issue in WSNs since sensors are generally deployed in unprotected environments and vulnerable to security attacks. The security algorithms have to be integrated with routing protocols to provide authenticity, condentiality, and integrity of transmitted data. Most of the existing routing protocols implement dierent security mechanisms to achieve the security goals. Any conflict among these measures may create vulnerabilities in the network. Therefore, to ensure energy eciency and minimisation of the implementation gap, energy ecient secure routing protocols have to be designed using a common security framework.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Information and Communication Technology
Science, Environment, Engineering and Technology
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31

Huang, Jie. "Efficient Support for Application-Specific Video Adaptation." PDXScholar, 2006. https://pdxscholar.library.pdx.edu/open_access_etds/2670.

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As video applications become more diverse, video must be adapted in different ways to meet the requirements of different applications when there are insufficient resources. In this dissertation, we address two sorts of requirements that cannot be addressed by existing video adaptation technologies: (i) accommodating large variations in resolution and (ii) collecting video effectively in a multi-hop sensor network. In addition, we also address requirements for implementing video adaptation in a sensor network. Accommodating large variation in resolution is required by the existence of display devices with widely disparate screen sizes. Existing resolution adaptation technologies usually aim at adapting video between two resolutions. We examine the limitations of these technologies that prevent them from supporting a large number of resolutions efficiently. We propose several hybrid schemes and study their performance. Among these hybrid schemes, Bonneville, a framework that combines multiple encodings with limited scalability, can make good trade-offs when organizing compressed video to support a wide range of resolutions. Video collection in a sensor network requires adapting video in a multi-hop storeand- forward network and with multiple video sources. This task cannot be supported effectively by existing adaptation technologies, which are designed for real-time streaming applications from a single source over IP-style end-to-end connections. We propose to adapt video in the network instead of at the network edge. We also propose a framework, Steens, to compose adaptation mechanisms on multiple nodes. We design two signaling protocols in Steens to coordinate multiple nodes. Our simulations show that in-network adaptation can use buffer space on intermediate nodes for adaptation and achieve better video quality than conventional network-edge adaptation. Our simulations also show that explicit collaboration among multiple nodes through signaling can improve video quality, waste less bandwidth, and maintain bandwidth-sharing fairness. The implementation of video adaptation in a sensor network requires system support for programmability, retaskability, and high performance. We propose Cascades, a component-based framework, to provide the required support. A prototype implementation of Steens in this framework shows that the performance overhead is less than 5% compared to a hard-coded C implementation.
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Chen, Sheng. "Future development trends of optical transport network infrastructure an infrastructural framework for metropolitan-based optical transport networks : a field test of a Chinese ISP and a case study of a Chinese electrical power company /." Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20070822.115714/index.html.

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33

Tsietsi, Mosiuoa. "Prototyping a peer-to-peer session initiation protocol user agent /." [S.l. : s.n.], 2008. http://eprints.ru.ac.za/1115/.

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34

Klingestedt, Kashmir. "Client-Server Communications Efficiency in GIS/NIS Applications : An evaluation of communications protocols and serialization formats." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233581.

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Geographic Information Systems and Network Information Systems are important tools for our society, used for handling geographic spatial data and large information networks. It is therefore important to make sure such tools are of high quality. GIS/NIS applications typically deal with a lot of data, possibly resulting in heavy loads of network traffic. This work aims to evaluate two different communications protocols and serialization formats for client-server communications efficiency in GIS/NIS applications. Specifically, these are HTTP/1.1, HTTP/2, Java Object Serialization and Google's Protocol Buffers. They were each implemented directly into a commercial GIS/NIS environment and evaluated by measuring two signature server calls in the system. Metrics that were examined are call duration, HTTP overhead size and HTTP payload size. The results suggest that HTTP/2 and Google's Protocol Buffers outperform HTTP/1.1 and Java Object Serialization respectively. An 87% decrease in HTTP overhead size was achieved when switching from HTTP/1.1 to HTTP/2. The HTTP payload size is also shown to decrease with the use of Protocol Buffers rather than Java Object Serialization, especially for communications where data consist of many different object types. Concerning call duration, the results suggest that the choice of communications protocol is more significant than the choice of serialization format for communications containing little data, while the opposite is true for communications containing much data.
Geografiska informationssystem och nätverksinformationssystem är viktiga redskap för vårt samhälle, vilka används för hantering av geografisk data och stora informationsnätverk. Det är därför viktigt att se till att sådana system är av hög kvalitet. GIS/NIS-applikationer behandlar vanligtvis stora mängder data, vilket kan resultera i mycket nätverkstrafik. I det här arbetet utvärderas två olika kommunikationsprotokoll och serialiseringsformat för kommunikationseffektivitet mellan klient och server i GIS/NIS-applikationer. Specifikt är dessa HTTP/1.1, HTTP/2, Java Objektserialisering och Googles Protocol Buffers. De implementerades var och en i en kommersiell GIS/NIS-miljö och utvärderades genom mätningar av två signaturanrop i systemet. De aspekter som observerades är kommunikationstiden, mängden HTTP-overhead och mängden HTTP-payload. Resultaten tyder på att HTTP/2 och Googles Protocol Buffers presterar bättre än HTTP/1.1 respektive Java Objektserialisering. En 87% minskning av mängden HTTP overhead uppnåddes då HTTP/1.1 ersattes med HTTP/2. En minskning av mängden HTTP payload observeras också med användning av Protocol Buffers snarare än Java Objektserialisering, särskilt för kommunikationer där data innehåller många olika objekttyper. Gällande kommunikationstiden tyder resultaten på att valet av kommunikationsprotokoll påverkar mer än valet av serialiseringsformat för kommunikationer med små mängder data, medan motsatsen gäller för kommunikationer med mycket data.
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35

Barreto, Fernando. "Esquema de caminhos emergenciais rápidos para amenizar perdas de pacotes." Universidade Tecnológica Federal do Paraná, 2008. http://repositorio.utfpr.edu.br/jspui/handle/1/127.

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Os backbones IP utilizam protocolos de roteamento do tipo estado do enlace para definir as rotas corretamente. Em situações de mudança na topologia, como uma falha, esses protocolos necessitam de um tempo para reagir e encontrar novas rotas. Durante esse tempo, as rotas ficam instáveis com alta taxa de pacotes perdidos e queda na confiabilidade do backbone. Esse trabalho propõe uma abordagem pró-ativa denominada Esquema de Caminhos Emergenciais Rápidos para auxiliar o protocolo de roteamento OSPF a reduzir a taxa de pacotes perdidos durante esse período. Essa abordagem realiza cálculos reutilizando a base de informações de roteamento do OSPF para gerar esses caminhos emergenciais, que são representados na tabela de encaminhamento através de marcas. Essas marcas são utilizadas então para guiar corretamente os pacotes no contorno de uma falha. Essa abordagem é avaliada em representações de topologias artificiais e reais, e também em simulação para analisar qual o ganho obtido na redução de pacotes perdidos em relação ao OSPF original. A abordagem desenvolvida demonstra resultados bastante satisfatórios em termos de extensão dos caminhos de recuperação utilizados e quantidade de informações extras adicionadas na tabela de encaminhamento em relação à abordagem concorrente.
IP network backbones use link state routing protocols to find correct routes. In face of a topology change, e.g. a failure, these protocols need some time to react to it in order to find new routes. During this time, the routes become unstable, causing high packet loss rate and depreciation of backbone reliability. This work presents a proactive approach named Fast Emergency Paths Schema to help the OSPF routing protocol during the convergence period in order to reduce packet loss rate. The approach conducts calculations reusing the routing information base of the OSPF in order to generate these emergency paths, which are represented in the forwarding table as marks. These are then used to guide the packets to correctly bypass a failure. The approach is evaluated by using various artificial and real topologies, and a simulation is also implemented in order to analyze the packet loss rate reduction in relation to the original OSPF. The analysis yielded satisfactory results in terms of the extension of the recovery paths used and of the amount of extra information added to the forwarding table in relation to the concurrent approach.
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36

Bošeľa, Jaroslav. "Návrh a implementace síťového kolektoru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-412992.

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This master’s thesis deals with description of information protocol of network flow, mainly definition of Cisco NetFlow version 9. Describes it’s features, message format and attributes of transmitted data. The thesis is primarly focused onto NetFlow v9 transmitted template, which defines fileds and data in consecutive data flow. The essence of the thesis consists in implementation of simple NetFlow v9 parser, which has been programmed in Python prog.language, it’s tests of captured UDP data from file and port capture testing on development server in lab. There is a possibility of saving captured and parsed data into prepared database within implementation as output from capturing.
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37

Uesono, Marcelo Mitsutoshi. "Protocolos de justiça para redes opticas em anel." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/276229.

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Orientadores: Nelson Luis Saldanha da Fonseca, Marcos Rogerio Salvador
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação
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Resumo: Em redes ópticas em anel com slotting, slots de tamanhos fixos circulam continuamente pelo anel transportando pacotes de dados entre os nós. Em tais redes, um slot, ocupado com pacotes de um nó, tem seu conteúdo removido somente pelo próprio nó de origem. Entretanto, é possível remover o conteúdo do slot no nó de destino, técnica conhecida como remoção no destino, o que permite que um slot seja utilizado mais de uma vez em cada ciclo, o que é conhecido como reutilização espacial. Esta prática aumenta consideravelmente a vazão do anel. Entretanto, se o acesso aos slots não for controlado, injustiças podem ocorrer devido a oportunidades desbalanceadas de acesso ao meio oferecido aos nós. Para previnir um acesso injusto ao meio, a ocupação dos slots é controlada pelos protocolos de controle de acesso ao meio (MAC), que distribuem os slots entre os nós, oferecendo oportunidades justas do acesso ao meio. Os protocolos MAC seguem políticas de justiça, que são regras que determinam a divisão justa dos recursos do anel. Os protocolos MAC que oferecem justiça entre nós são comuns na literatura, entretanto, estes protocolos ignoram a justiça entre conexões TCP (Transmission Control Protocol)o Nesta dissertação, três novos protocolos são apresentados: LCR-SD, TCP-Fair e RVQ. O protocolo LCR-SD distribui a largura de banda baseada na política de justiça entre pares origem-destino, o protocolo RVQ oferece justiça entre conexões TCP e o protocolo de TCP -Fair oferece a justiça entre as conexões TCP mantendo a justiça entre nós. Os protocolos são comparados através de simulações realizadas no Network Simulator (NS-2). Resultados indicam que os protocolos LCR-SD, TCP-Fair e RVQ oferecem uma vazão superior ao protocolo Metaring. Além disso, apresenta-se um estudo sobre o impacto do tamanho dos slots no transporte de tráfego da Internet
Abstract: In slotted ring networks, slots of fixed size continuously circulate the ring transferring data packets between nodes. In such networks, a slot occupied by packets from one node, has its content removed only by the source node. However, it is possible to remove the packet content in the destination node, technique known as destination removal, which allows a slot to be used more than once in each cycle, leading to spatial reuse, which increases considerably the throughput. However, if the access to the slots is not regulated, unfairness may occur due to unbalanced medium access opportunities offered to the nodes. To prevent unfair access to the medium, the occupation of the slots is regulated by a Medium Access Control protocol (MAC), which distributes the slots among the nodes, offering fair access opportunities to the medium. MAC protocols comply with fairness policies, which are rules that determine the fair distribution of the ring resources. MAC protocols that offer fairness among nodes are common in the literature, however, these protocols ignore the fairness among TCP (Transmission Control Protocol) connections. In this dissertation, three new protocols are presented: LCR-SD, TCP-Fair and RVQ. The LCR-SD protocol distributes the bandwidth based on the source-destination node fairness policy, the RVQ protocol offers fairness among TCP connections and the TCP-Fair protocol offers fairness among TCP connections and maintains fairness among nodes. The protocols are compared through simulations using the Network Simulator (NS- 2). Results indicate that the protocols LCR-SD, TCP-Fair and RVQ offer a superior throughput compared to the Metaring protocol. Moreover, a study on the impact of the slot size on the transport of Internet traffic is presented.
Mestrado
Redes de Computadores
Mestre em Ciência da Computação
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38

Lutshete, Sizwe. "An analysis of the correlation beween packet loss and network delay on the perfomance of congested networks and their impact: case study University of Fort Hare." Thesis, University of Fort Hare, 2013. http://hdl.handle.net/10353/d1006843.

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In this paper we study packet delay and loss rate at the University of Fort Hare network. The focus of this paper is to evaluate the information derived from a multipoint measurement of, University of Fort Hare network which will be collected for a duration of three Months during June 2011 to August 2011 at the TSC uplink and Ethernet hubs outside and inside relative to the Internet firewall host. The specific value of this data set lies in the end to end instrumentation of all devices operating at the packet level, combined with the duration of observation. We will provide measures for the normal day−to−day operation of the University of fort hare network both at off-peak and during peak hours. We expect to show the impact of delay and loss rate at the University of Fort Hare network. The data set will include a number of areas, where service quality (delay and packet loss) is extreme, moderate, good and we will examine the causes and impacts on network users.
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39

Nascimento, Marcelo Ribeiro. "Proposta e validação de nova arquitetura de roteamento IP com separação de planos." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259642.

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Orientadores: Maurício Ferreira Magalhães, Christian Rodolfo Esteve Rothenberg
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Os roteadores atuais implementam uma arquitetura verticalmente integrada composta de uma camada de software e um hardware proprietários. Este modelo resulta em soluções de alto custo e inviabiliza a experimentação de novas idéias. Em contrapartida, existem alternativas de alta flexibilidade baseadas em software e, consequentemente, de baixo custo. Entretanto, essas soluções apresentam baixo desempenho. Motivado pela disponibilidade de uma API aberta para programação do plano de encaminhamento (ex. OpenFlow), esta dissertação apresenta uma proposta de arquitetura de roteamento IP com separação de planos. Trata-se de uma abordagem que procura combinar o alto desempenho de hardwares de prateleira (commodities) com a flexibilidade de uma pilha de roteamento executada remotamente em computadores de uso geral. O grande desafio é garantir confiabilidade, escalabilidade e desempenho à rede, a partir de um controle remoto e centralizado sobre uma arquitetura que permita maior flexibilidade no mapeamento entre os elementos de controle e encaminhamento. O resultado corresponde a uma nova proposta de roteamento IP com perspectivas promissoras do ponto de vista do custo e da flexibilidade. Com o objetivo de avaliar a arquitetura proposta foi desenvolvido um protótipo com base em uma versão simplificada do modelo. Os resultados da avaliação apresentados nesta dissertação comprovam a viabilidade da arquitetura
Abstract: Today's networking gear follows the model of computer mainframes, where closed source software runs on proprietary hardware. This approach results in expensive solutions and prevents equipment owners to put new ideas into practice. In contrast, recent alternatives of highly flexible softwarebased routers promise low cost and programmability at the expense of low performance. Motivated by the availability of an open API to control packet forwarding engines (i.e., OpenFlow), we propose a commodity IP routing architecture that combines the line-rate performance of commercial hardware with the flexibility of open source routing stacks (remotely) running on general-purpose computers. The challenge is to ensure reliability, scalability and performance to a network running a remote and centralized control plane architecture that allows a flexible mapping between the control and forwarding elements. The outcome is a novel point in the design space of cost-effective IP routing solutions with far-reaching implications. The initial experimental evaluation of our prototype implementation validates the feasibility of the design
Mestrado
Engenharia de Computação
Mestre em Engenharia Elétrica
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40

Mafra, Samuel Baraldi. "Análise do uso de técnicas de codificação de rede e comunicação full-duplex em rádio cognitivo underlay." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1378.

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CAPES
Nesta tese são apresentados dois esquemas de comunicação cooperativa para redes cognitivas limitadas pelo máximo nível de interferência aceito na rede licenciada. Os esquemas são avaliados em função da probabilidade de outage, que representa a probabilidade de falha na comunicação. No primeiro esquema, a rede não licenciada é composta por uma fonte, um relay full-duplex dedicado e um destino. Contrastando com trabalhos anteriores, o modelo do sistema considera o enlace direto entre o transmissor e o destino não licenciados como informação útil. A análise apresentada inclui o efeito da interferência da rede licenciada, assim como, a auto-interferência no relay. Um esquema de alocação ótima de potência (OPA) é proposto. A estratégia OPA pode escolher entre dois modos de operação, a cooperação entre a fonte e relay ou transmissão direta da fonte. O esquema OPA proposto possui o melhor desempenho em termos de probabilidade de outage quando comparado com métodos concorrentes. No segundo esquema, o uso de codificação de rede é aplicado em um cenário cognitivo onde múltiplos usuários não licenciados cooperam entre si para enviar mensagens independentes ao destino não licenciado, ou seja, neste cenário não existem nós dedicados à transmissão da informação de um parceiro como no primeiro esquema. Os esquemas codificação de rede dinâmica (DNC) e codificação de rede dinâmica generalizada (GDNC) são avaliados em um cenário cognitivo, considerando um limite máximo de interferência na rede licenciada e uma potência máxima de transmissão para os nós não licenciados. A cooperação com codificação de rede é capaz de aumentar consideravelmente o desempenho da rede não licenciada quando comparado ao esquema decodifica-e-encaminha seletivo (SDF) e à transmissão direta sem cooperação. Adicionalmente, uma expressão analítica é derivada para a capacidade de -outage, sendo esta a máxima taxa de informação obtida pelos usuários não licenciados dada uma probabilidade de outage alvo. No intuito de maximizar a capacidade de -outage do esquema cognitivo GDNC, o número ótimo de pacotes de paridade é encontrado através do algoritmo de Dinkelbach. Uma comparação entre os dois esquemas propostos nesta tese, avaliando o uso de comunicação full-duplex no esquema com codificação de rede, é proposta como um direcionamento para trabalhos futuros.
In this work are presented two schemes of cooperative communication for cognitive radio networks limited by the maximum interference level acceptable at the licensed network. The schemes are evaluated in function of the outage probability, that is the probability of failure in the communication. In the first scheme, the unlicensed network is composed by a source, a dedicated full-duplex relay and a destination. Differently of previous works, the system model considers the direct link between the unlicensed transmitter and destination as useful information. The presented analysis includes the effect of the licensed interference, as well as, the self interference at the relay. Moreover, an optimal power allocation (OPA) scheme is proposed. The OPA strategy can choose between two modes of operation, cooperation between source and relay or source transmission only. The proposed OPA scheme has the best performance, when this is compared with concurrent schemes. In the second scheme, the use of network coding is applied in a cognitive scenario where multiple unlicensed users cooperate to send independent messages to the unlicensed destination, thus, in this scenario there are not dedicated nodes to transmission of partner information as in the first scheme. The dynamic network coding (DNC) and generalized dynamic network coding (GDNC) schemes are evaluated in a cognitive scenario, under a given maximum interference constraint set by the licensed network, as well as, the maximum transmit power limit of the unlicensed sources. The cooperation with network coding can provide significant gains in terms of performance, when compared to non cooperative or selective decode-and-forward (SDF) cooperative techniques. Also, a closed-form equation is obtained for the -outage capacity, which is the maximum information rate achieved by the secondary sources given a target outage probability. In order to maximize the -outage capacity of the cognitive GDNC, the optimum number of parity packets is found through Dinkelbach algorithm. A comparison between the two proposed schemes in this thesis, by analysing the use of full-duplex communication in the scheme with network coding, is proposed as a direction for future works.
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41

Scarlato, Michele. "Sicurezza di rete, analisi del traffico e monitoraggio." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3223/.

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Il lavoro è stato suddiviso in tre macro-aree. Una prima riguardante un'analisi teorica di come funzionano le intrusioni, di quali software vengono utilizzati per compierle, e di come proteggersi (usando i dispositivi che in termine generico si possono riconoscere come i firewall). Una seconda macro-area che analizza un'intrusione avvenuta dall'esterno verso dei server sensibili di una rete LAN. Questa analisi viene condotta sui file catturati dalle due interfacce di rete configurate in modalità promiscua su una sonda presente nella LAN. Le interfacce sono due per potersi interfacciare a due segmenti di LAN aventi due maschere di sotto-rete differenti. L'attacco viene analizzato mediante vari software. Si può infatti definire una terza parte del lavoro, la parte dove vengono analizzati i file catturati dalle due interfacce con i software che prima si occupano di analizzare i dati di contenuto completo, come Wireshark, poi dei software che si occupano di analizzare i dati di sessione che sono stati trattati con Argus, e infine i dati di tipo statistico che sono stati trattati con Ntop. Il penultimo capitolo, quello prima delle conclusioni, invece tratta l'installazione di Nagios, e la sua configurazione per il monitoraggio attraverso plugin dello spazio di disco rimanente su una macchina agent remota, e sui servizi MySql e DNS. Ovviamente Nagios può essere configurato per monitorare ogni tipo di servizio offerto sulla rete.
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Sazima, Ricardo. "PLEX MPLS : analise, projeto e implementação de uma plataforma para experimentos com MPLS com suporte a QoS." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259128.

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Orientador: Mauricio Ferreira Magalhães
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Dados a banda de transmissão atualmente disponível, o protocolo (IP) utilizado para transmitir a maior parte de tráfego e a quantidade de tráfego e seus requisitos de aos, a Engenharia de Tráfego (TE, de Traffic Engineering) tomou-se um componente cada vez mais importante nas redes de comunicações. O padrão do IETF para enncaminhamento roteamento entitulado Multi-Protocol Label Switching (MPLS) preenche lacunas importantes neste cenário e é peça chave das metodologias de TE mais sofisticadas. Nesta dissertação é apresentado um modelo genérico de TE e uma proposta para uma Plataforma para Experimentos com MPLS (PLEX MPLS) que permite que o usuário defina, execute, e analise configurações de Engenharia de Tráfego com MPLS em uma rede IP. Os principais objetivos da PLEX MPLS são: . Estudo da tecnologia MPLS e suporte a outros trabalhos em andamento no contexto do grupo de estudos em MPLS do DCA . Experimentos com engenharia de tráfego com MPLS: validação das tecnologias e conceitos relacionados . Experimentos didáticos em disciplinas de laboratório de redes. Os principais conceitos de TE e MPLS são apresentados como referência, bem como uma descrição do NIST Switch, a plataforma MPLS escolhida para este trabalho. A análise, projeto e implementação da PLEX MPLS são apresentados, pois formam parte significativa do trabalho desenvolvido. A PLEX não só utiliza, como também estende as funcionalidades oferecidas pelo NIST Switch a fim de oferecer um esquema de TE mais completo e eficiente. Na fase de análise, vemos quais os principais requisitos para a implementação desta plataforma, seguindo uma metodologia de Engenharia de Software. Na fase de projeto, vemos as soluções propostas para os problemas identificados na fase de análise e temos uma especificação dos componentes a serem implementados. Na fase seguinte, discutimos a implementação das principais características dos componentes da PLEX, justificando as decisões tomadas. Para validar a implementação da PLEX de acordo com sua proposta, foram realizados alguns experimentos em uma rede de testes com tráfego real. A execução destes experimentos é descrita e seus resultados analisados. Os resultados obtidos assinalam claramente a importância e utilidade de esquemas de TE baseada em MPLS. Uma interessante metodologia para TE, compilada a partir de várias propostas, é apresentada. Finalmente, apontam-se caminhos a seguir em um trabalho futuro de refinamento da PLEX
Abstract: Given the bandwidth currently available, the protocol (IP) used to transmit most Internet traffic, the quantity of traffic produced and its QoS requirements, Traffic Engineering (TE) has become an increasingly important component of communications networks. IETF's standard for forwarding/routing, which is entitled Multi-Protocol Label Switching (MPLS), presents important solutions in this scenario playing a major role in more sophisticated TE methodologies. This work presents a generic methodology for TE and a proposal for a Platform for Experiments with MPLS (PLEX MPLS) which allows the user to define, execute and analyze Traffic Engineering configurations with MPLS in an IP network. The main goals of PLEX MPLS are: . Study of the M PLS technology and support of other ongoing works with M PLS in the DCA . Traffic Engineering experiments with MPLS: validation of the related concepts and technologies . Support of didactic experiments in academic disciplines. The main concepts of MPLS and TE are presented as reference, as well as a brief description of NIST Switch, the MPLS software chosen for the PLEX MPLS implementation. The analysis, project and implementation of PLEX MPLS are presented, since are significant part of the developed work. PLEX not only uses, but also extends NIST Switch functionalities to offer a more complete and efficient TE scheme. In the analysis phase the main requirements for the PLEX implementation are specified, following a well-known Software Engineering methodology. The solutions found for the problems identified in the analysis phase are presented in the project phase alongside with a specification of the components that will be implemented. In the next phase, the implementation of PLEX is discussed focusing on the most important characteristics of PLEX components and justifying the implementation ecisions. In order to validate PLEX implementation and its proposal, some experiments were made in a test network with reallive traffic. These experiments are described and its results analyzed. The results obtained clearly indicate the importance and utility of TE schemes based on MPLS. Also an interesting TE methodology compiled from several proposals is presented. Finally, possible improvements and future work on PLEX MPLS are indicated.
Mestrado
Engenharia de Computação
Mestre em Engenharia Elétrica
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43

Talau, Marcos. "NGWA: esquema de controle de congestionamento para TCP baseado na banda disponível." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/304.

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O controle de congestionamento padrão do TCP apresenta vários problemas; ele não consegue distinguir se o pacote foi perdido por falha no enlace ou por descarte de pacotes devido a um congestionamento de rede (se a falha foi no enlace não há necessidade de ativar os mecanismos de controle de congestionamento); e o correto ajuste de sua taxa de transmissão requer informação de perdas de pacotes. Neste trabalho é apresentado o new generalized window advertising (NGWA), que é um novo esquema de controle de congestionamento para o TCP. O NGWA traz informações da banda disponível da infraestrutura de rede para os pontos finais da conexão TCP. Seu desempenho foi comparado com TCP New Reno, RED e o TCP padrão via simulações com o software NS-3, considerando topologias de rede largamente citadas na literatura. O NGWA foi, também, implementado e testado no Linux (versão 2.6.34). O novo método demonstrou ser superior aos comparados, apresentando uma operação mais estável, melhor justiça e menor taxa de perda de pacotes, considerando o elenco de testes realizados.
The TCP congestion control mechanism in standard implementations presents several problems; he cannot distinguish if the packet was lost by link failure or by congestion in the net (if the fault was in the link there is no need to active congestion control mechanisms); and the right adjust of your transmission rate requires information from packet loss. This work presents the new generalized window advertising (NGWA), which is a new congestion control scheme for TCP. The NGWA provides information considering the available bandwidth of the network infrastructure to the endpoints of the TCP connection. Results obtained by the NGWA approach were compared with those from TCP New Reno, RED, and standard TCP (using the network simulator NS-3), considering network topologies widely cited in the literature. A NGWA Linux implementation is also presented. The new method proved to be superior when compared with the traditional approaches, presenting a more stable operation, better fairness and lower packet loss, considering the set of tests carried out.
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44

Mascarenhas, da Veiga Alves Manoel Eduardo. "Characterisation of end-to-end performance for web-based file server respositories." Thesis, 2001. http://hdl.handle.net/2440/107771.

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Investigates the behaviour of TCP bulk file transfer application sessions in a broadband access environment. Introduces some concepts for evaluating network behaviour: a path instability parameter for analyzing different TCP connections; a minimum RTT delay and a minimum typical path for estimating path characteristics between a client and application servers.
Thesis (Ph.D.) -- University of Adelaide, Dept. of Electrical and Electronic Engineering, 2001
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45

Friedrich, Jan. "Advanced Protocols for Peer-to-Peer Data Transmission in Wireless Gigabit Networks." 2020. https://ul.qucosa.de/id/qucosa%3A72056.

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This thesis tackles problems on IEEE 802.11 MAC layer, network layer and application layer, to further push the performance of wireless P2P applications in a holistic way. It contributes to the better understanding and utilization of two major IEEE 802.11 MAC features, frame aggregation and block acknowledgement, to the design and implementation of opportunistic networks on off-the-shelf hardware and proposes a document exchange protocol, including document recommendation. First, this thesis contributes a measurement study of the A-MPDU frame aggregation behavior of IEEE 802.11n in a real-world, multi-hop, indoor mesh testbed. Furthermore, this thesis presents MPDU payload adaptation (MPA) to utilize A-MPDU subframes to increase the overall throughput under bad channel conditions. MPA adapts the size of MAC protocol data units to channel conditions, to increase the throughput and lower the delay in error-prone channels. The results suggest that under erroneous conditions throughput can be maximized by limiting the MPDU size. As second major contribution, this thesis introduces Neighborhood-aware OPPortunistic networking on Smartphones (NOPPoS). NOPPoS creates an opportunistic, pocket-switched network using current generation, off-the-shelf mobile devices. As main novel feature, NOPPoS is highly responsive to node mobility due to periodic, low-energy scans of its environment, using Bluetooth Low Energy advertisements. The last major contribution is the Neighborhood Document Sharing (NDS) protocol. NDS enables users to discover and retrieve arbitrary documents shared by other users in their proximity, i.e. in the communication range of their IEEE 802.11 interface. However, IEEE 802.11 connections are only used on-demand during file transfers and indexing of files in the proximity of the user. Simulations show that NDS interconnects over 90 \% of all devices in communication range. Finally, NDS is extended by the content recommendation system User Preference-based Probability Spreading (UPPS), a graph-based approach. It integrates user-item scoring into a graph-based tag-aware item recommender system. UPPS utilizes novel formulas for affinity and similarity scoring, taking into account user-item preference in the mass diffusion of the recommender system. The presented results show that UPPS is a significant improvement to previous approaches.
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46

Won, Chulho. "Eager data transfer mechanism for user-level network protocol." Thesis, 2004. http://hdl.handle.net/1957/28731.

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This dissertation investigates the use of a hardware mechanism called Eager Data Transfer (EDT) for achieving the reduction of communication latency for user-level network protocol. To reach the goal, the dissertation addresses the following research issues. First, the development of a communication system performance evaluation tool called Linux/SimOS is presented. Linux/SimOS provides a full system profiling capability to allow measurement at various level including hardware, operating system, and application. Second, the performance analysis of network protocols is presented. For the assessment of overhead related to network protocol operation, Linux/SimOS was used to perform the detailed latency measurements for TCP/IP, UDP/IP, and M-VIA network protocols. Finally, EDT is proposed for reducing communication latency. Since the data transfer time constitutes a significant portion of overall communication latency, the reduction of data transfer time leads to low communication latency. EDT is based on cache coherence interface hardware for reducing data transfer overhead during network protocol operation. Our simulation result shows that EDT is very effective in attaining low communication latency compared to the DMA-based approaches.
Graduation date: 2005
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47

Kruger, Angela. "Data integrity in a steel manufacturing environment with special reference to Columbus Stainless Steel." Thesis, 2012. http://hdl.handle.net/10210/4506.

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M.Comm.
In manufacturing companies where raw material is transformed into an endproduct, data pertaining to that transformation process are transported from the physical machine (workstation) to a central database and visa versa. To ensure a successful end-product creation, the company needs to ensure that the data being transported is correct, accurate and trustworthy at all times. As unreliable data seems to be a general problem for large manufacturing companies an investigation was launched to establish what integrity problems are being experienced and possible solutions to these problems in manufacturing companies such as Columbus Stainless Steel. On completion of the investigation it was found that the main causes for late deliveries and data fixes being performed was that the data being transmitted at the source was not always the same data received at the destination, hence a lack of data integrity during data transmission was identified. As it was decided to reduce or eliminate the integrity causes rather than correcting the incorrect results the data transportation process was analyzed. During the analysis the main causes for data integrity problems (errors) were identified. In the environment being investigated, data strings (messages) were created at the workstation and then transported via the use of a transporter (protocol) over an established network to the destination database. The more complex the contents of the message (data string), the more advanced features were needed within the functionality of the protocol to ensure the accurate and correct transmission and processing. Once the main causes for these data integrity errors were identified the investigation was broadened to incorporate the search for various protocols with the ability to reduce or eliminate the causes identified previously.
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48

Chen, Jing. "Design and analysis of dynamic packet scheduling protocols for unidirectional optical buses /." 2008. http://proquest.umi.com/pqdweb?did=1654494041&sid=5&Fmt=2&clientId=10361&RQT=309&VName=PQD.

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49

Sewnath, Gajadhar. "A packet radio system for an industrial data network." Thesis, 1992. http://hdl.handle.net/10413/6898.

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This project was undertaken for a commercial electronics company, CONTROL LOGIC (CONLOG) which is involved in the research, design, development and manufacture of data acquisition, control, energy management and automotive equipment. Currently CONLOG uses an inhouse token passing local area network CONET for industrial data communications.The need had arisen to provide a means of data communication amongst widely geographically distributed remote terminal units (RTUs) generating demands at a very low duty cycle. A need for communications between RTUs and a centralised controller was also required. In addition to this, multihop communications between the RTUs was required. Packet switching using a broadcast radio network provides an efficient means of achieving this. An investigation into to the various media access control protocols and contention techniques using packet radio was carried out. The various media access techniques were compared with respect to throughput and normalised delay. This led to the selection of a media access scheme for the packet radio network using RTUs. A protocol specification control is centralised or Interconnect Organisation.The switching protocol (OSI) for the packet radio network, in which distributed, was done. The architechure of specified adheres to the Open Systems model of the International Standards.An experimental packet switching radio network was implemented using the protocol specification defined above. The packet radio network (PACNET) uses existing off the shelf radios and purpose built hardware for the remote terminal units. The thesis describes methods of data communications suitable for widely dispersed industrial data communications, the selection of the packet switching media access methods and control protocols, and the design and implementation of the prototype system.
Thesis (M.Sc.Eng.)-University of Natal, 1992.
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Lin, Chin-Sheng, and 林欽盛. "Research of high-speed data transmission for 8B/10B and 64B/66B protocols applied between FPGAs." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/67144357801355059970.

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碩士
國立聯合大學
電機工程學系碩士班
102
The purpose of this thesis is to achieve high-speed serial communication between FPGAs with custom control code for 8B / 10B protocol, and it has been applied to the Xilinx ML605 development board and Altera Stratix IV (Signal Integrity Development Kit) development board with linking test. We have successfully reached 3.125Gbps data transmission rate. The high-speed serial communication analysis with 8B/10B, Aurora 8B/10B and Aurora 64B / 66B protocol will be included here. keywords : FPGA , 8B/10B protocol, Aurora 8B/10B protocol, Aurora 64B/66B protocol, high-speed serial communication
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