Made available in DSpace on 2015-04-11T14:02:49Z (GMT). No. of bitstreams: 1 paulo cesar.pdf: 2356898 bytes, checksum: 3103951fb7cb8f61e3fd1e03b8817b22 (MD5) Previous issue date: 2013-07-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Software-Defined Network (SDN) is a new paradigm that allows the development of innovative network management applications and provides a new way to look for the resolution of problems which exist throughout the Internet today. In order to simplify the task of managing the network most of SDN architectures uses a centralized network management approach. However, such approach raises, among other problems, the issue of a single point of failure, that can compromise the proper functioning of the network. A proven method to achieve a higher level of network resilience is to use a replication technique. The aim of this work is to investigate: (1) how different replication techniques relate to each other, (2) how each one performs on the task of providing resilience to a SDN, and (3) which technique is the most suitable for different scenarios. Replication techniques are mainly classified in two types: passive and active replication.This work is one of the first to address this issue. For the purpose of proof-of-concept, the replication mechanisms implemented work for networks with one switch enabled for SDN protocol. Our results show that replication is a suitable way to increase resilience in a SDN and to build these services for networks using SDN is straightforward and much less complex. / Redes definidas por software (Software Defined Networking ou SDN) é um novo paradigma para o desenvolvimento de aplicações inovadoras de gestão de redes e uma nova forma de olhar para a resolução de muitos problemas que existem em toda a Internet hoje. A arquitetura mais popular para a implantação deste paradigma é o gerenciamento de rede centralizado, uma vez que o seu uso permite simplificar a tarefa complexa e difícil de controlar os serviços de uma rede. Um dos problemas levantados pela abordagem de controle centralizado e amplamente discutido na literatura é a questão de falha em um único ponto da rede, que pode comprometer negativamente o funcionamento de toda ela. Um método comprovado para alcançar um maior nível de tolerância a falhas é a utilização da técnica de replicação. O objetivo deste trabalho é dividido em três partes: (1) comparar diferentes técnicas de replicação, (2) verificar como cada uma desempenha a tarefa de proporcionar resiliência a uma SDN, e (3) investigar qual técnica é a mais adequada para diferentes cenários. Técnicas de replicação são principalmente classificadas em dois tipos: de replicação passiva e ativa. Este trabalho é um dos primeiros a tratar este problema. Para fins de prova-de-conceito, os mecanismos de replicação implementados funcionam para redes com um switch habilitado para o protocolo SDN. Nossos resultados mostram que a replicação é uma forma adequada para aumentar a resiliência em uma SDN e construir estes serviços para redes utilizando SDN é muito menos complexo e simples.

Submitted by Marta Toyoda (1144061@mackenzie.br) on 2018-02-07T23:34:13Z No. of bitstreams: 2 VICTOR MORALES DIONISIO.pdf: 15019971 bytes, checksum: cc45d6dd4e5209047a4c19cbfbe5eb00 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Paola Damato (repositorio@mackenzie.br) on 2018-02-22T13:35:18Z (GMT) No. of bitstreams: 2 VICTOR MORALES DIONISIO.pdf: 15019971 bytes, checksum: cc45d6dd4e5209047a4c19cbfbe5eb00 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-22T13:35:18Z (GMT). No. of bitstreams: 2 VICTOR MORALES DIONISIO.pdf: 15019971 bytes, checksum: cc45d6dd4e5209047a4c19cbfbe5eb00 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-07 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Fundo Mackenzie de Pesquisa / This paper presents the characteristics of two recent technologies on the scienti c and telecommunications community: the Advanced Television Systems Committee (ATSC) 3.0; the Software De ned Radio (SDR). Later, the usage of the three is studied by developing the modulator of the ATSC 3.0 system with SDR technique and the GNURadio Companion (GRC). In order to prove the integrity of the modulator implementation, the transmitted signal is tested with the Dektec receiver, composed by the DTA-2131 hardware and the Atsc3Xpress software. All the codes are developed in C++ language and the tests made in GRC. Such tests prove the integrity of the implementation since the receiver was able to demodulate the signal correctly, and that the SDR platform is a suitable tool for prototyping and researching digital TV transmission systems. / Este projeto apresenta as definições e características de duas tecnologias recentes na comunidade científica e de telecomunicações: o Advanced Television Systems Committee (ATSC) 3.0; o Rádio Definido por Software, do inglês Software Defined Radio (SDR). Posteriormente, investiga a combinação delas, desenvolvendo um modulador do sistema ATSC 3.0 por meio da técnica de SDR, utilizando o software GNURadio Companion (GRC). Com o intuito de comprovar a integridade da implementação do modulador, o sinal _e testado com o receptor, composto pelo hardware DTA-2131 e software Atsc3Xpress da Dektec. O desenvolvimento do sistema _e feito por meio de algoritmos computacionais em linguagem C++ e os testes são feitos no GRC. Tais testes comprovam a integridade da implementação uma vez que o receptor foi capaz de demodular o sinal corretamente, e que a plataforma de SDR _e uma ferramenta adequada para prototipagem e pesquisa de sistemas de transmissão de TV digital.

Detta projekt har haft som mål att skapa ett redundant SDN-nätverk som ska ligga som grund för ett fiktivt företag. Företeaget ska kunna använda nätverket som vi bygger upp för att vidareutveckla detta och anpassa det efter verksamhetens behov. Nätverket byggs upp med mininet som används för att simulera en nätverksmiljö. Det fiktiva företaget ska sedan bara kunna lyfta ut nätverket från mininet ut till ett riktigt nätverk. Nätverkets funktioner, såsom protokollen STP och LACP implementeras med hjälp av programmeringsspråket python. / The goal for this project is to setup a redundant Software Defined Network for a fictive company. The company should be able to use the network for future network extension. The network will be built in mininet. Mininet is a software that is used to simulate a real network environment. The company should also be able to take the simulated network in mininet and implement it in to a real network. The protocols STP and LACP are implemented in the network by means of the programming language python.

Context Traditional storage systems are proving to be inefficient to handle the growing storage need of a modern IT organization. The need for a cost effective and scalable storage framework has led to the development of a Software Defined Storage (SDS) solution. SDS can be defined as an enterprise class distributed storage solution that uses standard hardware, with all the important storage and management functions performed by an intelligent software. Configuring and maintenance of these storage clusters require converting an SDS from any unknown state to a predefined, known state. This configuration of the SDS is best done with minimal human intervention, to ensure minimal errors and save the man hours spent in the configuration process. Objectives A tool for automatic configuration of a SDS storage cluster has been designed and implemented. The tool has later been used to study the man hours saved in the configuration of the SDS cluster. The study also involves a cost-benefit analysis to estimate the break-even point for such a tool to motivate the automation of a SDS cluster configuration process. Methodology In this study, experts from the field of Software Defined Storage have been interviewed to identify interesting and most common states of a SDS cluster. Later a tool was build such that it communicates with the underlying SDS storage cluster to configure it into one of the identified final states. This tool built was later used to conduct experiments wherein the amount of man hours saved by automating the process of cluster configuration was calculated.    Results The tool built was validated through results obtained from the experiments which show that the work time involved in the process of cluster configuration is reduced by 90% - 96% (based on the complexity of the cluster configuration). Also, the lead times of the configuration process are similar when configuring simple states but is greatly reduced by automation when performing complex configurations. Conclusions Similar to any other software automation, the process of automating the configuration of a distributed storage cluster has proven to be beneficial. Automating the process of cluster configuration saves time, reduces human errors induced in the configuration process and improves repeatability of the configuration process. Through the cost-benefit analysis of the complete process, the use of the tool beyond 20 days is deemed profitable for the organization.

Emerging Software Defined Networking (SDN) technology has provided excellent flexibility to large-scale networks in terms of control, management, security, and maintenance. On the other hand, recent years witnessed a tremendous growth of the critical infrastructure networks, namely the Smart-Grid, in terms of its underlying communication infrastructure. Such large local networks requires significant effort in terms of network management and security. We explore the potential utilization of the SDN technology over the Smart Grid communication architecture. Specifically, we introduce three novel SDN deployment scenarios in local networks of Smart Grid. Moreover, we also investigate the pertinent security aspects with each deployment scenario along with possible solutions. On the other hand, we conducted experiments by using actual Smart Grid communication data to assess the recovery performance of the proposed SDN-based system. The results show that SDN is a viable technology for the Smart Grid communications with almost negligible delays in switching to backup wireless links.

The ability to use Software Defined Radio (SDR) in the civilian mobile applications will make it possible for the next generation of mobile devices to handle multi-standard personal wireless devices and ubiquitous wireless devices. The original military standard created many beneficial characteristics for SDR, but resulted in a number of disadvantages as well. Many challenges in commercializing SDR are still the subject of interest in the software radio research community. Four main issues that have been already addressed are performance, size, weight, and power. This investigation presents an in-depth study of SDR inter-components communications in terms of total link delay related to the number of components and packet sizes in systems based on Software Communication Architecture (SCA). The study is based on the investigation of the controlled environment platform. Results suggest that the total link delay does not linearly increase with the number of components and the packet sizes. The closed form expression of the delay was modeled using a logistic function in terms of the number of components and packet sizes. The model performed well when the number of components was large. Based upon the mobility applications, energy consumption has become one of the most crucial limitations. SDR will not only provide flexibility of multi-protocol support, but this desirable feature will also bring a choice of mobile protocols. Having such a variety of choices available creates a problem in the selection of the most appropriate protocol to transmit. An investigation in a real-time algorithm to optimize energy efficiency was also performed. Communication energy models were used including switching estimation to develop a waveform selection algorithm. Simulations were performed to validate the concept.

Information and Communication Technology (ICT) is a catalyst for economic development and has been seen to provide new business opportunities and a source of competitive advantage. The acute ICT skills gap in South Africa is widely acknowledged. Such a shortage has cost the South African economy dearly, resulting in the government adopting a multi-pronged approach to the problem. The various interventions have yielded limited success leaving room for other players to contribute to the solution. The Cisco Academy programme, executed through the establishment of Cisco Academies in educational institutions, is a professional education programme focused on the provision of computer networking skills and other basic information technology technical skills. Its comprehensive approach has seen it playing a complementary role to those of the government and other stakeholders. This study focused on the factors that affect Cisco Academy performance. The primary objective was to improve the academic performance of the Cisco Academies in South Africa. More specifically the study assessed the effect of instructor quality, use of technology tools, multi-culture needs, motivation, supporting infrastructure and accessibility on academy performance. The sample consisted of 166 respondents from five Cisco Academies in South Africa. Techniques such as multiple regression analysis, two sample t-tests and analysis of variance were employed on the empirical data. It was established that instructor quality and use of technology tools were the significant determinants of academy performance. It was also established that the Cisco Academy programme is making a significant contribution towards addressing the ICT skills shortage. A number of recommendations are made for the government, Cisco Academies and Cisco systems itself. Recommendations for future research are also provided.

The promise of Internet of Things (IoT) and mass connectivity has brought many applications and along with them many new challenges to be solved. Recognizing sensor networks as one of the main applications of IoT, this dissertation focuses on solutions for IoT challenges in both single-hop and multi-hop communications. In single-hop communications, the new IEEE 802.11ah and its Group Synchronized Distribution Coordination Function (GS-DCF) is studied. GS-DCF categorized nodes in multiple groups to solve the channel contention issue of dense networks. An RSS-Based grouping strategy is proposed for the hidden terminal problem that can arise in infrastructure-based single hop communications. For multi-hop communications, Physical Layer Network Coding (PNC) is studied as a robust solution for multi-hop packet exchange in linear networks. Focusing on practical and implementation issues of PNC systems, different challenges have been addressed and a Software Defined Radio (SDR) PNC system based on USRP devices is proposed and implemented. Finally, extensive simulation and experimental results are presented to evaluate the performance of the proposed algorithms in comparison with currently used methods. / Graduate

Today, data centers host a wide variety of applications which generate a mix of diverse internal data center traffic. In a data center environment 90% of the traffic flows, though they constitute only 10% of the data carried around, are short flows with sizes up to a maximum of 1MB. The rest 10% constitute long flows with sizes in the range of 1MB to 1GB. Throughput matters for the long flows whereas short flows are latency sensitive. This thesis studies various data center transport mechanisms aimed at either improving flow completion time for short flows or throughput for long flows. Thesis puts forth two data center transport mechanisms: (1) for improving flow completion time for short flows (2) for improving throughput for long flows. The first data center transport mechanism proposed in this thesis, FA-DCTCP (Flow Aware DCTCP), is based on Data Center Transmission Control Protocol (DCTCP). DCTCP is a Transmission Control Protocol (TCP) variant for data centers pioneered by Microsoft, which is being deployed widely in data centers today. DCTCP congestion control algorithm treats short flows and long flows equally. This thesis demonstrate that, treating them differently by reducing the congestion window for short flows at a lower rate compared to long flows, at the onset of congestion, 99th percentile of flow completion time for short flows could be improved by up to 32.5%, thereby reducing their tail latency by up to 32.5%. As per data center traffic measurement studies, data center internal traffic often exhibit predefined patterns with respect to the traffic flow mix. The second data center transport mechanism proposed in this thesis shows that, insights into the internal data center traffic composition could be leveraged to achieve better throughput for long flows. The mechanism for the same is implemented by adopting the Software Defined Networking paradigm, which offers the ability to dynamically adapt network configuration parameters based on network observations. The proposed solution achieves up to 22% improvement in long flow throughput, by dynamically adjusting network element’s QoS configurations, based on the observed traffic pattern.

In mobile cloud computing (MCC), rich mobile application data is processed at the cloud infrastructure by reliving resource limited mobile devices from computationally complex tasks. However, due to the ubiquitous and mobility nature, providing time critical rich applications over remote cloud infrastructure is a challenging task for mobile application service providers. Therefore, according to the literature, close proximity placement of cloud services has been identified as a way to achieve lower end-to-end access delay and thereby provide a higher quality of experience (QoE) for rich mobile application users. However, providing a higher Quality of Service (QoS) with mobility is still a challenge within close proximity clouds. Access delay to a closely placed cloud tends to be increased over time when users move away from the cloud. However, reactive resource relocation mechanism proposed in literature does not provide a comprehensive mechanism to guarantee the QoS and as well as to minimize service provisioning cost for mobile cloud service providers. As a result, using the benefits of SDN and the data plane programmability with logically centralized controllers, a resource allocation framework was proposed for IaaS mobile clouds with regional datacenters. The user mobility problem was analyzed within SDN-enabled wireless networks and addressed the possible service level agreement violations that could occur with inter-regional mobility. The proposed framework is composed of an optimization algorithm to provide seamless cloud service during user mobility. Further a service provisioning cost minimization criteria was considered during an event of resource allocation and inter-regional user mobility.