Orientador: Nelson Luis Saldanha da Fonseca / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-13T20:11:45Z (GMT). No. of bitstreams: 1 Michel_NeilaFernanda_M.pdf: 1961141 bytes, checksum: f4470a332c9b5f764b7bd3b912c27db1 (MD5) Previous issue date: 2008 / Resumo: O protoloco TCP Reno começou a operar em 01 de Janeiro de 1983. Desde sua concepção, houveram expressivos avanços nas tecnologias de transmissão de dados, como a introdução de enlaces ópticos e de satélites, 'que permitem altas taxas de transmissão. O TCP Reno continua sendo o protocolo padrão na Internet. Entretanto existem inúmeras dificuldades na sua operação, que causam baixo desempenho em redes com produto banda-atraso elevado, devido ao mecanismo de atualização do tamanho da janela de congestionamento. Para superar suas deficiências, vários protocolos variantes do TCP Reno têm sido propostos com o objetivo de melhorar a utilização de recursos em redes de alta velocidade, e por esta razão são denominados "Protocolos para Redes de Alta Velocidade" . Para que as proposições de variantes do TCP levem a protocolos que operem eficientemente em redes com alto valor do produto banda-atraso, é necessário que se avalie quais variações da dinâmica do crescimento da janela de transmissão são efetivas. Nesta dissertação avalia-se um conjunto de protocolos variantes do TCP para redes de alta velocidade através de simulações. Diversas propriedades importantes para protocolos do tipo TCP são investigadas / Abstract: The importance of the Reno TCP protocol started operating in January 01 st, 1983. Since this milestone, there were expressive advances on data transmission technologies, such as those of optical fibers and satellite channels which allow high transmission rates on long distances. Reno TCP remains the Internet standard protocol. However, its operation presents several dificulties in networks with high bandwidth-delay product, producing poor performance due its window congestion mechanism. In order to overcome its deficiencies, several variants have been proposed with the aim of enhancing its utilization in high speed networks. These variants are generally called "High Speed Networks Protocols". Transmission chàracteristics, properties and performance evaluation are essencial to the identification of problems and avoidance of poor performance. In this dissertation a set of TCP variants protocols for high speed networks is evaluated. Several important properties of these protocols are investigated / Mestrado / Redes de Computadores / Mestre em Ciência da Computação

Este trabalho propõe a integração de técnicas de sensoriamento dinâmico, redes de dados sem fio e internet. A implementação dos nós da rede visa permitir o monitoramento de objetos que se movem tanto numa rede interna, limitada a uma edificação, quanto numa rede externa, através de coordenadas GPSs (Global Position Systems). A rede sem fio, que utiliza o protocolo ZigBee, é composta por sensores, atuadores e lâmpadas e é dotada de mobilidade através de controles remotos1. A rede ZigBee é integrada, através de um gateway, a uma rede TCP/IP para permitir o monitoramento e a atuação remota sobre ela, via um servidor HTTP e/ou uma rede de dados celular (GPRS), que, quando fora do alcance dos nós da rede ZigBee interna, torna-se responsável pelo envio de coordenadas GPS na rede externa, garantindo a onipresença do monitoramento. Além das adaptações na pilha TCP/IP e o desenvolvimento de um software que utiliza a rede GPRS para envio de coordenadas GPS, destacam-se, como contribuições originais desta tese: (i) a solução de problemas da pilha ZigBee original no tocante a endereçamento, que impossibilitava a mobilidade na rede - desta forma, uma nova técnica de endereçamento seqüencial foi implementada com sucesso; (ii) novo código que simulou o AES (Advanced Encryption Standard), tanto para encriptação quanto para desencriptação dos dados. Testes para validação dos protótipos desenvolvidos são apresentados / This MSc Thesis proposes the integration of dynamic sensing techniques, wireless data network and Internet. The implementation of network nodes aims to allow monitoring of moving objects, either inside an internal network, limited to one area, or in an external network, through GPS\'s (Global Position Systems). The wireless network, which uses the ZigBee protocol, is composed of sensors, actuators and lamps, and is endowed with mobility through remote controls. Thus, it is integrated, through a gateway, to a TCP / IP network to allow remote monitoring and acting on it via an HTTP server and / or a mobile data network (GPRS), responsible for sending the GPS coordinates on the external network, ensuring the ubiquity of monitoring. Further to adaptations in the TCP/IP stack and the development of a software that uses GPRS protocol to send GPS coordinates, the main contributions of this work are: (i) proposal of a new addressing technique, based on a sequential numbering of nodes, instead of the standard one, thus solving problems related to mobility in the network; (ii) proposal of a new security code to emulate AES (Advanced Encryption Standard), either for data encryption or decryption. Tests for validation of the developed prototypes will be presented

Made available in DSpace on 2016-04-18T21:39:45Z (GMT). No. of bitstreams: 4 Antonio Carlos GIANOTO1.pdf: 620239 bytes, checksum: aa779772dff23531ab717870d36823d3 (MD5) Antonio Carlos GIANOTO2.pdf: 1522259 bytes, checksum: 928d1a566cc9977b69a13b358fe13a50 (MD5) Antonio Carlos GIANOTO3.pdf: 2036577 bytes, checksum: 4ef7b886a0d20792d494deb085435041 (MD5) Antonio Carlos GIANOTO4.pdf: 1519186 bytes, checksum: cce13633bbc1cf7d5714a8dd727dd008 (MD5) Previous issue date: 2006-06-29 / Fundo Mackenzie de Pesquisa / The aim of this elaboration is to present a study of the migration process involved transforming the digital PBX (Private Branch Exchange), TDM (Time Division Multiplex), SPC (Stored Program Control) based platforms of corporate communications on technology to converged IP (Internet Protocol) systems supported by the TCP/IP (Transmission Control Protocol/Internet Protocol) protocol. This proposal analyzes the necessary interventions in order to preserve the investments made in these platforms, integrating them to existent data networks. Beside other benefits presented in this work, one key advantage is the possibility to transport voice over an existing data infrastructure, optimizing usage of carrier connections. / O objetivo desta dissertação é o de apresentar um estudo do processo de migração de plataformas de voz PABX (Private Automatic Branch Exchange) TDM (Time Division Multiplex) de comunicações corporativas baseadas na tecnologia CPA-T (Controle por Programa Armazenado estágio de comutação temporal digital), para sistemas convergentes suportados pelo protocolo TCP/IP (Transmission Control Protocol/Internet Protocol). São analisadas as intervenções necessárias para esta migração, preservando ao máximo os investimentos efetuados nestas plataformas, integrando-as as redes de dados existentes. Dentre outras vantagens apresentadas no texto, destaca-se a otimização dos acessos fornecidos pelas operadoras de telecomunicações pelo compartilhamento da infra-estrutura da rede de dados para o tráfego de sinais de voz.

Capturar e analisar pacotes de dados que trafegam pelas redes são tarefas essenciais para os administradores de redes. Estas tarefas ajudam na detecção de anomalias nos sistemas e na verificação do estado atual da rede. Existem várias aplicações que desempenham este papel para o sistema operacional GNU/Linux. Estes programas também exportam informações para os usuários e outras aplicações de várias maneiras. Entretanto, não exportam estas informações de forma hierárquica. Esta pesquisa propõe uma arquitetura alternativa aos sistemas atuais. Nossa arquitetura exporta pacotes de dados em uma estrutura hierárquica de arquivos e diretórios. Além disso, por se tratar de uma arquitetura modular, filtros adicionais, desenvolvidos por terceiros, podem ser adicionados ao sistema. A arquitetura proposta acompanha uma implementação de referência: o sistema de arquivos virtuais netsfs (Network Statistics File System), que funciona em espaço de núcleo (kernel space). A arquitetura e o sistema de arquivos netsfs, propostos nesta pesquisa, apresentam um método alternativo para exibir os pacotes de redes. Os resultados mostraram uma aparente melhoria no que diz respeito à vazão da rede. / Capturing and analyzing data packets flowing across networks are essential tasks for network administrators. These tasks help to detect anomalies in the systems and check the current status of a network. There are software applications for the GNU/Linux operating system which perform such tasks. These tools also export their information to users and other applications in different ways. However, current systems do not export this information in a hierarchical manner. This research introduces an alternative architecture to current systems. Our architecture exports data packets in a hierarchical structure of directories and files. Furthermore, since this is a modular architecture, additional third-party filters can be developed and loaded into the system. The proposed architecture comes with a reference implementation: the pseudo file system netsfs (Network Statistics File System), in kernel space. The architecture and the pseudo file system netsfs, developed in this research, introduce an alternative method to display data packets. Results show an apparent improvement regarding network throughput

This diploma thesis deals with the design and implementation of an application suitable for the anonymization of PCAP files. The thesis presents TCP/IP model and for each layer highlights attributes that can be used to identify real people or organizations. Some of the anonymization methods suitable to modify highlighted attributes and sensitive data are described. The implemented application uses TShark tool to parse byte data of PCAP format to JSON format that is used in the application. TShark supports lots of network protocols which allows the application to anonymize various attributes.  Anonymization process is controlled by anonymization politics that can be customized by adding new attributes or anonymization methods.

This master’s thesis is focused on behaviour of the TCP/IP protocol on free-space optical link which is affected by the effect of atmospheric turbulence. This causes fluctuation of the received optical power and therefor bit error rate changes. In the simulation model short-time bit error rate is calculated from random generated received optical signal and then used in time-domain analysis of the OMNeT++ network simulator. A buffer in transmitter is designed based on simulation results. It pauses the data transmitting in cases of FSO link outage. This method is then implemented into FPGA device.

This thesis focuses on designing and developing a centralized management and configuration solution for the thin clients offered by the OldanyGroup s.r.o. company. The purpose of this application is to simplify the thin client administration and control for customers as well as to improve the competitiveness of the whole thin client solution offered by the company.

This master’s thesis is focused on behaviour of the TCP/IP protocol on free-space optical link which is affected by the effect of atmospheric turbulence. This causes fluctuation of the received optical power and therefor bit error rate changes. In the simulation model short-time bit error rate is calculated from random generated received optical signal and then used in time-domain analysis of the OMNeT++ network simulator. A buffer in transmitter is designed based on simulation results. It pauses the data transmitting in cases of FSO link outage. This method is then implemented into FPGA device.

The growing number of players in Massively Multiplayer Online games puts a heavy load on the network infrastructure and the general-purpose CPU of the game servers. A game server’s network stack processing needs equal treatment to the game-related processing ability. It is a fact that the networkcommunication tasks on the CPU reach the same order of magnitude as the game-related tasks, and the computing capability of the CPU can be a factor that limits the maximum number of players. Therefore, CPU offloading is becoming vital. FPGAs play an essential role in dedicated computation and network communication due to their superiority in flexibility and computation-oriented efficiency. Thus, an FPGA can be a good hardware platform to implement a network stack to replace the CPU in processing the network computations. However, most commercial and open-source network stack IPs support only one or few connections. This thesis project explores a network server on FPGA, implemented in RTL, that can handle multiple connections, specialized in the TCP protocol. The design in this project adds a cached memory hierarchy that provides a filter against port numbers of multiple connections from the same application and an Application Layer Controller, based on an open-source Ethernet, to increase the number of TCP connections further. A proof of concept was built, and its performance was tested. As a result, the TCP server on the FPGA was designed to handle a maximum of 40 configurable connections, but only 25 connections could be maintained during operation due to operational latency constraints. This FPGA server solution provides a latency of 1 ms in LAN. The babbling idiot and out-of-order packet transfer tests from clientswere also performed to guarantee robustness. During testing, poor performance in Packet Loss and Packet Error Handling was noted. In the future, this issue needs to be addressed. In addition, further investigations of methods for expanding the cache need to be done to allow handling more clients. / Det växande antalet spelare i Massively Multiplayer Online-spel belastar nätverksinfrastrukturen och spelservrarnas CPU:er. En spelservers förmåga att bearbeta nätverksstacken måste behandlas lika med den spelrelaterade bearbetningsförmågan. Det är ett faktum att nätverkskommunikationsuppgifterna på processorn når samma storleksordning som de spelrelaterade uppgifterna, och processorns beräkningsförmåga kan vara en faktor som begränsar det maximala antalet spelare. Därför blir avlastning av CPU-viktig. FPGA:er spelar en viktig roll i dedikerad beräkning och nätverkskommunikation på grund av dess överlägsenhet vad gäller flexibilitet och beräkningsorienterad effektivitet. Således kan en FPGA vara en bra hårdvaruplattform för att implementera en nätverksstack, för att ersätta CPU:n vid bearbetning av nätverksberäkningsarna. Men, de flesta kommersiella och öppna källkodsnätverksstack- IP:er stöder dock bara en eller ett fåtal anslutningar. Detta examensarbete utforskar en nätverksserver på FPGA, implementerad mha RTL, som kan hantera flera anslutningar, specialiserad på TCP-protokollet. Designen i detta projekt lägger till en cachad minneshierarki som ger ett filter mot portnummer för flera anslutningar från samma applikation och en Application Layer Controller, baserad på öppen källkod för Ethernet, för att öka antalet TCP-anslutningar ytterligare. Ett proof of concept byggdes och dess prestanda testades. Som ett resultat designades TCP-servern på FPGA:n att kunna hantera maximalt 40 konfigurerbara anslutningar, men endast 25 anslutningar kunde bibehållas under drift på grund av driftsfördröjningar. Denna FPGA-serverlösning ger en latens på 1 ms i LAN. Tester inkluderande den babblande idioten och out-of-order paketöverföring från klienter utfördes också för att garantera robusthet. Under testningen noterades dålig prestanda i paketförlust och paketfelshantering. I framtiden måste denna fråga åtgärdas. Dessutom behöver ytterligare undersökningar av metoder för att utöka cachen göras för att kunna hantera fler klienter.

There are a number of known architectural patterns for TCP/IP server design. I present a survey of design choices based on some of the most common of these patterns. I have demonstrated, with working code samples, that most of these architectural patterns are readily portable between UNIX and Windows NT platforms without necessarily incurring significant performance penalties. / Computing / M. Sc. (Computer Science)