Transmitted data logging in routers is the main point of this semestral project. The suggestion of a system for data flows logging in routers and selection of suitable technology, that is used by implementation of the system within this thesis, is based on this analysis. In the thesis, a law responsibility of router administrator for transmitting data is analysed. In the next part, a general introduction to issue of data logging in computer networks including basic description of protocols and fundamentals of standard communication models is presented. Analysis of real enviroment is following. Suggestion and implementation of the system is described too. In the last part a reached results of this thesis are revealed.

This study investigates how Swedish internet service providers (ISP) choose a Wi-Fi-Router for use by private customers. The study investigates the process of choosing a Wi-Fi-Router and what features the companies prioritize during the process. These features can be aspects such as security, speed, capacity, Wi-Fi standard and price. The study seeks to answer how the decision-making process is carried out in the companies, but also how the Wi-Fi-Routers features are prioritized during the decision-making process.  This was investigated using qualitative methods in the form of semi-structured interviews. The interviews were held remotely, which allowed for a larger spread of respondents. After the interviews, the data was coded using thematic analysis to arrive at the results of the study.  The study identified several different phases during the decision-making process that ISP’s go through. After identifying the phases, they were placed in a model which seeks to describe the decision-making process for all ISPs.  The most important aspect during the decision-making process was the price. The remaining aspects were decided by the Wi-Fi-Router's price and compromises had to be made to lower the price to a reasonable level for both the company and the customer. In addition to the price, the companies aimed to find a balance between the other features, where compromises can be made for features they consider to be less important.

<p>Routers are probably the most important component of a NoC, as the performance of the whole network is driven by the routers’ performance. Cost for the whole network in terms of area will also be minimised if the router design is kept small. A new application specific processor architecture for implementing NoC routers is proposed in this master thesis, which will be called µNP (Micro-Network Processor). The aim is to offer a solution in which there is a trade-off between the high performance of routers implemented in hardware and the high level of flexibility that could be achieved by loading a software that routed packets into a GPP. Therefore, a study including the design of a hardware based router and a GPP based router has been conducted. In this project the first version of the µNP has been designed and a complete instruction set, along with some sample programs, is also proposed. The results show that, in the best case for all implementation options, µNP was 7.5 times slower than the hardware based router. It has also behaved more than 100 times faster than the GPP based router, keeping almost the same degree of flexibility for routing purposes within NoC.</p>

A Internet pode não atender às necessidades exigidas por aplicações sensíveis a atraso tais como voz, video ou até jogos em redes. A distância de saltos entre o cliente e o servidor, o congestionamento dos links e a aleatoriedade do caminho do pacote, podem causar atrasos. Existem motivações e até implementações de infra-estruturas alternativas para atender necessidades não garantidas pela Internet. Um exemplo é o projeto Rede COMEP, que propõe uma rede alternativa a fim de diminuir a distância e aumentar a capacidade entre os usuários (alunos e professores) e o conteúdo. Esta tese propõe uma infra-estrutura de rede de alta velocidade, exclusiva para aplicações sensíveis a atraso. A rede, denominada de IXnet, origina-se de experimentos de roteamento compartilhado por meio do IXP, estudo do tráfego de uma aplicação sensível a atraso e uso de simulador de rede. O uso da IXnet pode ampliar a frente de negócios para as operadoras e usuários que fazem uso de aplicações sensíveis a atraso, melhorando a qualidade na prestação de seus serviços. / The Internet may does not meet all the demands required by applications sensitive to delay. Voice, video or even game applications demand low delay. The distance of hops between client and server, link traffic and the ramdomness of the package path, may cause delays. There is motivation and even implementation of alternative infra-structure to improve access. One example is the COMEP Network project, that proposes an alternative network in order to comply with the specific demands of such applications. This thesis proposes a high speed infra-structure network, exclusive for delay sensitive applications. This network, named IXnet, has it\'s origins in experiments with shared routing IXP, traffic studies of a sensitive to delay application and use of network simulator. The use of IXnet may increase the business front for operators and users that utilize sensitive to delay applications, improving the quality of the services provided.

A Internet pode não atender às necessidades exigidas por aplicações sensíveis a atraso tais como voz, video ou até jogos em redes. A distância de saltos entre o cliente e o servidor, o congestionamento dos links e a aleatoriedade do caminho do pacote, podem causar atrasos. Existem motivações e até implementações de infra-estruturas alternativas para atender necessidades não garantidas pela Internet. Um exemplo é o projeto Rede COMEP, que propõe uma rede alternativa a fim de diminuir a distância e aumentar a capacidade entre os usuários (alunos e professores) e o conteúdo. Esta tese propõe uma infra-estrutura de rede de alta velocidade, exclusiva para aplicações sensíveis a atraso. A rede, denominada de IXnet, origina-se de experimentos de roteamento compartilhado por meio do IXP, estudo do tráfego de uma aplicação sensível a atraso e uso de simulador de rede. O uso da IXnet pode ampliar a frente de negócios para as operadoras e usuários que fazem uso de aplicações sensíveis a atraso, melhorando a qualidade na prestação de seus serviços. / The Internet may does not meet all the demands required by applications sensitive to delay. Voice, video or even game applications demand low delay. The distance of hops between client and server, link traffic and the ramdomness of the package path, may cause delays. There is motivation and even implementation of alternative infra-structure to improve access. One example is the COMEP Network project, that proposes an alternative network in order to comply with the specific demands of such applications. This thesis proposes a high speed infra-structure network, exclusive for delay sensitive applications. This network, named IXnet, has it\'s origins in experiments with shared routing IXP, traffic studies of a sensitive to delay application and use of network simulator. The use of IXnet may increase the business front for operators and users that utilize sensitive to delay applications, improving the quality of the services provided.

<p>This thesis is an experimental study to evaluate the performance of different routing protocols in commonly deployed scenarios. This study mainly focuses on how much time each protocol consumes while recovering from a link-loss. It provides a guide line for the best routing solutions for ISPs, individual organizations or other types of providers which are engaged in providing reliable real-time communications to their subscribers. Such communications may include vehicle trafficking data, online TV programs (IPTV), voice over IP telephony (VoIP), weather forecasts, tracking systems and many other services which totally depend upon the reliability of real-time data streams, where any major loss in received data may bring significant negative results in the integrity of the entire application.</p><p>This work experimentally observes and tracks the loss of UDP packets when changes in the network topology occur. In order to make this observation in real network topologies, a custom-designed software tool has been developed. The tool is capable of delivering enough resources to a tester in evaluating the performance of routing protocols. All the test results derived from the software tool are statistically evaluated and on the basis of the outcome a better proposition can be provided to network administrators which face inconsistent topological issues.</p>

This thesis is an experimental study to evaluate the performance of different routing protocols in commonly deployed scenarios. This study mainly focuses on how much time each protocol consumes while recovering from a link-loss. It provides a guide line for the best routing solutions for ISPs, individual organizations or other types of providers which are engaged in providing reliable real-time communications to their subscribers. Such communications may include vehicle trafficking data, online TV programs (IPTV), voice over IP telephony (VoIP), weather forecasts, tracking systems and many other services which totally depend upon the reliability of real-time data streams, where any major loss in received data may bring significant negative results in the integrity of the entire application. This work experimentally observes and tracks the loss of UDP packets when changes in the network topology occur. In order to make this observation in real network topologies, a custom-designed software tool has been developed. The tool is capable of delivering enough resources to a tester in evaluating the performance of routing protocols. All the test results derived from the software tool are statistically evaluated and on the basis of the outcome a better proposition can be provided to network administrators which face inconsistent topological issues.

隨著網路訊務流量的快速成長和無線網路技術日漸成熟，如何妥善的運用有限的網路資源是一個成功擁塞控制機制要面對的根本問題。TCP為現行網路上最廣為使用的傳輸層協定，並且有許多的不同版本被提出來改進其效能上的問題，例如TCP NewReno，TCP SACK 及TCP Vegas等。然而由於TCP傳送端並未具有網路內部狀態的資訊，如可用頻寬等，大部份的TCP擁塞控制機制僅能依賴封包遺失做為觸發擁塞控制的指標。許多研究指出在無線的環境下TCP無法有效使用有限的資源並且分辨封包遺失的原因，因而造成整體的效能不佳。本篇研究提出一個藉由路由器輔助的TCP擁塞控制協定－TCP Muzha，仰賴路由器提供調速資訊，以幫助傳送端能不依靠封包遺失進行傳輸速度控制，並可更快速的達到最佳的傳輸速度。本研究同時提出模糊化的多層級速率調整方法，藉由動態所獲得的細膩資訊做擁塞避免及因應無線環境下因路由改變或傳輸介質不穩所產生的不必要傳輸速度減低。最後我們在NS2模擬器上對所提出的協定做效能評估，實驗結果顯示本協定除了能有效的避免擁塞外，並能減少不必要的降速及重傳封包的次數。 / Communication networks have evolved tremendously in the past decades. TCP is the most dominant and deployed end-to-end transport protocol across Internet today and will continue to be in the foresee future. It has numerous enhancing versions for wired network such as TCP Reno, TCP NewReno and TCP Vegas to improve the drawbacks of initial version of TCP. As IEEE 802.11 wireless network technology gains popularity, TCP is very likely to be popular for existing applications so far. However due to unawareness of network conditions, regular TCP is not able to fully control the limited resources and distinguish packet loss from congestion loss and random loss. Based on such implicit assumption, many studies have shown this would results in serious performance degradation in wireless environment. In this paper, we proposed a new TCP congestion control mechanism by router-assisted approach which is inspired by the concept of each wireless node playing the roles of terminal and router simultaneously. Based on the information feedback from routers, sender is able to adjust the sending speed dynamically in order to avoid overshooting problem. We also proposed a multilevel date rate adjustment method to control the date rate more precisely. Finally we evaluate the performance of our approach by NS2 simulator. Our proposed protocol has 5~10% higher throughput than TCP NewReno and much less number of retransmission. The fairness requirement is also achieved while our proposed protocol coexists with other major TCP variants.

Routers are probably the most important component of a NoC, as the performance of the whole network is driven by the routers’ performance. Cost for the whole network in terms of area will also be minimised if the router design is kept small. A new application specific processor architecture for implementing NoC routers is proposed in this master thesis, which will be called µNP (Micro-Network Processor). The aim is to offer a solution in which there is a trade-off between the high performance of routers implemented in hardware and the high level of flexibility that could be achieved by loading a software that routed packets into a GPP. Therefore, a study including the design of a hardware based router and a GPP based router has been conducted. In this project the first version of the µNP has been designed and a complete instruction set, along with some sample programs, is also proposed. The results show that, in the best case for all implementation options, µNP was 7.5 times slower than the hardware based router. It has also behaved more than 100 times faster than the GPP based router, keeping almost the same degree of flexibility for routing purposes within NoC.

A virtualização de rede surgiu como uma alternativa para contornar as limitações no uso compartilhado da infraestrutura atual da Internet. Com a virtualização, sob uma mesma estrutura física, ou substrato, é possível a construção de múltiplas redes virtuais, cada uma das quais empregando seus próprios protocolos, mecanismos de endereçamento e políticas de forma independente e isolada. Essas redes são formadas por roteadores, interfaces e enlaces virtuais mapeados sobre componentes reais. Por serem desacopláveis, os elementos virtuais trazem uma grande flexibilidade, sendo possível a construção de múltiplas redes sobrepostas para usuários com demandas distintas, por exemplo. Roteadores virtuais podem migrar de um roteador físico para outro, conforme necessidades de manutenção ou balanceamento de carga. Além disso, a possibilidade de se conduzir experimentos de rede em uma estrutura real, sujeita as condições de utilização e de tráfego que normalmente serão encontradas na prática, sem que se precise interromper a operação da rede, traz a possibilidade de se instalar poderosos e sofisticados ambientes de teste (testbeds ). Nesse ambiente, contudo, existem desafios de pesquisa a serem tratados e questões em aberto, em especial com relação ao gerenciamento de dispositivos. Em uma rede com suporte a virtualização, os roteadores físicos precisam ser gerenciados para que roteadores virtuais possam ser criados, modificados, duplicados, destruídos e movimentados. As interfaces de gerenciamento atuais, porém, não suportam tais ações de forma efetiva, obrigando o administrador dos dispositivos a realizar intervenções manuais através de interfaces de linha de comandos (CLIs) não padronizadas. Existe, assim, a necessidade de se definir uma interface de gerenciamento adequada para roteadores físicos que abrigam roteadores virtuais. Tendo como objetivo abordar estas questões, este trabalho consiste na investigação de uma solução para gerenciar roteadores virtuais. Para isto foram levantadas e definidas as principais ações de gerenciamento necessárias aos dispositivos, de forma integrada, visando a definição de uma interface padronizada de gerencia- mento para cenários heterogêneos de utilização. / Network virtualization emerged as an alternative to overcome limitations on use of the shared infrastructure of current Internet. With virtualization, over the same physical structure, or substrate, it is possible to build multiple virtual networks, each of them employing its own protocols, addressing mechanisms and policies, on an isolated and independent way. These networks are formed by virtual routers, interfaces and links mapped to real components. Because they are detachable, the virtual elements bring a great flexibility, being possible constructing many overlaid networks for users with different demands, for example. Virtual routers can migrate from one physical router to another as needed form maintenance or load balancing. Besides, the possibily of running network experiments in a real structure, subject to the conditions of use and traffic that will normally be encountered in practice, without interrupting network operation, make it possible to install powerfull and sofisticated testbeds. In such environment, however, there are research challenges to be managed and open questions, specially related to devices management. In a network with virtu- alization support, physicall routers must be managed so that virtual routers can be created, modified, copied, removed and moved. Nevertheless, current management interfaces do not support such action in an effictive way, compelling the devices manager to make manual interventions through non standardized command line interfaces (CLIs). So, there exist the need to define an adequate management interface for physicall routers that host virtual routers. Having as an objective to address these questions, this work consist in investi- gating a solution to manage virtual routers. For this, were raised and defined the main management actions required for devices, through an integrated way, aiming to define a standardized management interface for heterogeneous use scenarios.