To detect network changes and network troubles, Transpondertech needs a tool that can make network measurements. The purpose of this thesis has been to find measurable network properties that best reflect the status of a network, to find methods to measure these proerties and to implement these methods in one single tool. The resulting tool is called NetworkPerf and can measure the following network properties: availability, round-trip delay, delay variation, number of hops, intermediate hosts, available bandwidth, available ports, and maximum allowed packet size. Together, these properties give a good picture of the status of a network connection. The thesis also presents the methods used for meassuring these properties in the tool.

Ethernet functionality testing as a generic term used for checking connectivity,throughput and capability to transfer packets over the network. Especially in the packet-switchenvironment, Ethernet testing has become an essential part for deploying a reliable network.Over a long distance Ethernet testing parameter for analyzing network performance must havetwo devices attached and synchronized. Saab Microwave Systems is among the leading suppliers of radar systems developing groundbased,naval and air-borne radar systems. To ensure the correct functionality, the developerwants to verify the performance of computer network and looking for a suitable solution. A software application is required to verify and test the functionality of the Ethernet network andto verify the functionality and performance of the TCP/IP stack of newly added node. Theprograms shall be easily ported to different operating systems and must not depend on specificproduct properties.A software application, “NetBurst”, is developed for Ethernet functionality testing. Theapplication is vendor and platform independent.

Följande flerfallsstudie syftar till att empiriskt undersöka hur entreprenörer i Born Globals, det vill säga företag med en global vision och närvaro från grundandet, använder sina nätverk för att bli internationella. Tre fallstudier görs på olika Born Global-företag där entreprenörernas användning av nätverk i internationaliseringsprocessen undersöks genom semistrukturerade intervjuer. Fallstudierna analyseras först individuellt med hjälp av Johanson och Vahlnes internationaliseringsprocessmodell (2009) och sedan tillsammans i en jämförande analys för att dra fallgemensamma slutsatser. Resultatet visar att entreprenörerna använder sina existerande nätverk som ett verktyg för att genomföra en snabb internationaliseringsstrategi, genom att dra nytta av de kunskaper och resurser som finns inom nätverken. Nätverk fungerar både som en länk till indirekta relationer och som ett hjälpmedel för att minska det psykiska avståndet till internationella marknader. Således utnyttjas företagets nätverksposition för att identifiera affärsmöjligheter och för att lära sig, vilket möjliggör en verksamhetsförändring som driver internationaliseringen framåt.

In the industry there is a need for a more efficient way to troubleshoot machines that uses the protocol EtherNet/IP. The current methods is time consuming and complex. This project gather data from a simulated network and analyze the data. The result of the analyze is presented on a cellphone application with a description and a possible solution. The application is a cross-platform application developed with Cordova. The simulated network is created on a Raspberry Pi 2. The analyze is done on another Raspberry Pi 2 running the software Node-RED. Communication between the simulated network Raspberry and the cellphone is with Bluetooth Low Energy. Communication between cellphone and the server is with MQTT. There are several areas where this kind of application may suit. This project is in one specific area – troubleshooting EtherNet/IP.

Autorizada por el autor, pero con restricción para ser publicada a texto completo hasta el año 2015 / Esta memoria de título se enmarca en un proyecto que busca ofrecer una solución completa de monitoreo remoto. El control está enfocado en distintos dispositivos de medición en el rubro minero. El objetivo general consiste en el desarrollo de un punto de acceso, el cual permite la integración de una red de sensores con diferentes tecnologías de comunicaciones inalámbricas, tales como telefonía celular u otras compatibles con el protocolo TCP/IP. El sistema electrónico desarrollado adquiere la información desde una malla de sensores. Se utiliza un microcontrolador que procesa los datos de acuerdo a cada modo de funcionamiento. El objetivo es enviar la información de manera serial a un módem GSM/GPRS, en el caso de comunicación con la red de celular, o directamente a un conversor TCP/IP para tecnologías que utilizan este protocolo. Otra importante función del circuito integrado es configurar y controlar el punto de acceso, posibilitando automatizar el diseño realizado. El resultado es un producto que permite enviar datos desde los sensores de medición, hacia una red de telefonía celular o con destino de alguna tecnología basada en el protocolo TCP/IP. El prototipo implementado se caracteriza por ser escalable de acuerdo a los requerimientos del usuario, resolviendo una necesidad de la industria minera. Se concluye que es factible transmitir la información adquirida en distintos dispositivos, ubicados en diferentes zonas de una faena, de manera confiable y con una baja inversión. La empresa patrocinante de esta memoria ha manifestado su interés en comercializarlo, al ser un desarrollo que no tiene símil en el mercado. El trabajo futuro de esta implementación es poner en funcionamiento un sistema de respaldo para los datos, en momentos que se pierda conexión con la red de celular.

Ingeniero Civil Eléctrico / Las telecomunicaciones han evolucionado a un nivel tal que prácticamente se volvieron parte de la cotidianidad de la sociedad. La cantidad de aplicaciones y servicios disponibles así como la facilidad de acceso para gran parte de la población, ya sea por los bajos costos o por incluso gratuidad de conexión en lugares específicos, hacen que los requisitos de capacidad de transferencia de datos crezcan por lo tanto un óptimo uso de la capacidad del canal de transmisión es una necesidad. Esta necesidad es el foco de este trabajo. En este trabajo se propone un algoritmo que aborda la problemática a nivel de la capa de transporte. La capa de transporte utiliza el protocolo TCP para la transferencia segura e íntegra de los datos. Dado el funcionamiento de este protocolo, en donde se requiere confirmación de cada paquete recibido para la transmisión de datos (ACK), el Round-Trip Time (RTT) o retardo afecta drásticamente la velocidad de transmisión porque los paquetes en vuelo (que están siendo transferidos en el canal) ya que retrasan el crecimiento de la ventana de congestión. Este problema se acentúa particularmente en las redes de high Round-Trip Time (BDP) que corresponden a redes que tienen una alta capacidad de transferencia y RTT altos provocando que la cantidad de datos en vuelo sea elevado. El uso de TCP en las redes de alto BDP hace que las transmisiones sean muy dependientes del retardo y su mejor utilización de recursos corresponde a un área de estudio muy activa dentro de los algoritmos de evasión de congestión. En este trabajo se propone un método para encontrar la capacidad del canal de telecomunicaciones usando información que está disponible en la capa de transporte. El método consiste en utilizar una métrica basada en la distancia (secuencial o temporal) entre dos pérdidas y con esta información estimar la capacidad del canal. De esta forma se puede obtener un nivel de conocimiento sobre la red explícito en lugar de tantear mediante probing, método empleado por la mayoría de los protocolos existentes. Con la capacidad de canal estimada se calcula la ventana de congestión óptima teniendo varios factores en consideración como: throughput, TCP-friendliness y evasión de congestión. Además de conocer el valor de la capacidad del canal es necesario transmitir con ese conocimiento, por lo tanto también se propone la implementación de dos algoritmos de evasión de congestión en entorno a Linux. Las pruebas entregan resultados alentadores en donde se logra mantener la ventana de congestión muy cerca y establemente a la capacidad encontrada del canal. Esto se refiere principalmente a que las desviaciones estándar de la ventana de congestión de los módulos implementados tienen valores bajos y son alrededor de cuatro veces más pequeñas que las entregadas por el algoritmo Reno. Como resultado de este trabajo se publicaron en dos conferencias (Chilecon, IEEE Latincom) y se planea enviar a un journal.

Abstract Today's turbulent business environment, which is characterised by uncertainty and inability to predict the future, is extremely challenging. Mobile and Internet Protocol (IP) convergence, which brings together technologies and services from the mobile and Internet domains, has been identified as a discontinuity in the mobile telecommunications business. Additionally, new disruptive technologies are introduced together with new, complex products. This research addresses the approach that, along with introducing disruptive technologies in the mobile and IP convergence era, a new operational mode is needed in the new product development (NPD) process. This study approaches the operational mode from five perspectives: business environment, competence development, process renewal, running technology pilots, and product reliability. The research on the business environment area proposes two frameworks: one for building and describing and another for evaluating business models. The study on competence development arrives at the conclusion to propose a project management competence development framework. The third research perspective suggests that, when the business environment is changing, and disruptive technologies and continuous innovations create new kinds of products, it is likely that processes need renewal. Running technology pilots to involve customers early enough in new product development is proposed in the fourth research area. Finally, the fifth research topic proposes that it is essential for companies to be able to estimate the reliability of their products during the product development phase. It is concluded that the new operational mode when introducing disruptive technologies requires reconsidering business models, special attention to competence development, process renewal, customer involvement in new product development, and requires a means to guarantee software reliability.

Abstract The current Internet infrastructure must be architected to handle future media-rich, and content rich applications. The success of applications such as video-on-demand, multicast and content distribution depends on Quality of Service and bandwidth guarantees. Over the years, the Internet has encompassed many changes in traffic profiles and applications, in bandwidths and utilization, but the future Internet infrastructure necessitates a very different architecture supporting Quality of Service (QoS). A satellite, distinguished by features such as global coverage, bandwidth flexibility, broadcast, multicast, and reliability, is an excellent candidate to provide broadband integrated Internet access. The aim of this thesis is to explore suitability of satellite technologies for broadband Internet services with significant emphasis on the question of defining, assessing, and developing QoS models for satellite ATM and IP broadband networks with and without onboard processing. For the satellite Internet, Transmission Control Protocol (TCP) performance is degraded due to long propagation delays, link errors, and bandwidth asymmetry. In this thesis, for satellite ATM, fundamental questions such as buffer requirements, TCP/ATM efficiency, fairness, and multiple access are addressed through extensive simulations in a quantitative way. Buffer designs for TCP over satellite ATM Unspecified Bit Rate (UBR) service are performed. A buffer size equal to half the round trip delay-bandwidth product of the TCP connections provides high efficiency for TCP over satellite UBR. An extensive TCP analysis via simulation study for various TCP mechanisms and end system policies show that for satellite environment end system policies are more important than switch drop policies in terms of efficiency and fairness for World Wide Web traffic. A bandwidth allocation scheme is proposed and analytical model for supporting voice and video service over a broadband satellite network is developed. The study results demonstrate that non-contiguous allocation can afford higher gain in uplink utilizations. In this thesis, for the first time, Integrated Services and Differentiated Services based QoS architectures for broadband satellite IP networks are proposed and analyzed. In multimedia applications where User Datagram Protocol (UDP) is used along with TCP, a fair excess bandwidth allocation is not possible because TCP is congestion sensitive whereas UDP is congestion insensitive. An extensive simulation model is developed to study the effect of precedence levels for reserved rate utilization and fairness with different buffer management policies. The simulation results indicate that three levels of precedence are required for better utilization. Multiprotocol Label Switching (MPLS) over Satellite network has been proposed and a simulation model developed to study the throughput performance impacts for TCP and UDP. The traffic engineering of MPLS facilitates efficient and reliable network design to optimize the utilization of network resources and enhance the network QoS. A novel Code Division Multiple Access based Spread ALOHA single code multiple access scheme for broadband satellite return channel is proposed as an alternative to Multifrequency-Time Division Multiple Access based Digital Video Broadcasting-Return Channel via Satellite protocol. It is shown through Monte Carlo simulations that throughput for Spread ALOHA One Long Code equivalent to packet length, is better than Spread ALOHA One Code in which spreading sequence repeats every symbol. The reduction of throughput due to multi-user interference for different number of users is shown. Further research on QoS architectures, performance models for TCP enhancements, interworking functions, interoperability, and standardization efforts is included.

M.Sc. / Using the Internet for communication purposes constitutes a high risk, considering the security of such information. The protocol suite used on the Internet is the TCP/IP protocol suite, which consists of the Transmission Control Protocol (TCP) and the Internet Protocol (IP). In a bid to create a basis to support the newly conceptualised ideas, various areas of networking are briefly discussed in this dissertation. The first in this series of areas is that of the OSI layers. This model forms the basis of all networking concepts. The model describes seven layers, of which each performs a certain networking function. The TCP/IP protocol suite fits into this model. Network security and encryption methods are applied and followed to secure information on the Internet. These methods have been used over a long period of time and will also be used to support the newly conceptualised ideas. The main focus of this dissertation falls on the securing of certain parts of the information contained in the headers of both the Transmission Control Protocol (TCP) and the Internet Protocol (IP) in a bid to minimise the amount of data that may be inferred about the communicating parties from these headers. In addition, where multiple routes exist between hosts, the possibility of the deliberate distribution of a single message across these routes is examined. Such distribution will further complicate the task of a hacker attempting to gather information from TCP and IP headers. In addition, such distribution will minimise the possibility that a hacker may assemble a complete message from its constituent parts and that he/she may infer information about the message that cannot be inferred from the isolated parts. The length of a message sent between hosts is one simple example of such information.

Please read the abstract in the section 00front of this document / Dissertation (MSc (Computer Science))--University of Pretoria, 2006. / Computer Science / unrestricted