Software Defined Networking (SDN) is an emerging paradigm for network design and management. By providing network programmability and the separation of control and data planes, SDN offers salient features such as simplified and centralized management, reduced complexity, and accelerated innovation. Using SDN, the control and management of network devices are performed by centralized software, called controllers. In particular, Software-Defined Wide Area Networks (SD-WANs) have made considerable headway in recent years. However, SDN can be a double-edged sword with regard to network resilience. The great reliance of SDN on the logically centralized control plane has heightened the concerns of research communities and industries about the resilience of the control plane. Although the controller provides flexible and fine-grained resilience management features that contribute to faster and more efficient failure detection and containment in the network, it is the Achilles' heel of SDN resilience. The resilience of control plane has a great impact on the functioning of the whole system. The challenges associated with the resilience of the control plane should be addressed properly to benefit from SDN's unprecedented capabilities. This dissertation investigates the aforementioned issues by categorizing them into two groups. First, the resilient design of the control plane is studied. The resilience of the control plane is strongly linked to the Controller Placement Problem (CPP), which deals with the positioning and assignment of controllers to the forwarding devices. A resilient CPP needs to assign more than one controller to a switch while it satisfies certain Quality of Service (QoS) requirements. We propose a solution for such a problem that, unlike most of the former studies, takes both the switch-controller/inter-controller latency requirements and the capacity of the controllers into account to meet the traffic loads of switches. The proposed algorithms, one of which has a polynomial-time complexity, adopt a clique-based approach in graph theory to find high-quality solutions heuristically. Second, due to the high dynamics of SD-WANs in terms of variations in traffic loads of switches and the QoS requirements that further affect the incurred load on the controllers, adjustments to the controller placement are inevitable over time. Therefore, resilient switch reassignment and incremental controller placement are proposed to reuse the existing geographically distributed controllers as much as possible or make slight modifications to the controller placement. This assists the service providers in decreasing their operational and maintenance costs. We model these problems as variants of the problem of scheduling on parallel machines while considering the capacity of controllers, reassignment cost, and resiliency (which have not been addressed in the existing research work) and propose approximation algorithms to solve them efficiently. To sum up, CPP has a great impact on the resilience of SDN control plane and subsequently the correct functioning of the whole network. Therefore, tailored mechanisms to enhance the resiliency of the control plane should be applied not only at the design stage of SD-WANs but also during their lifespan to handle the dynamics and new requirements of such networks over time. / Graduate

Made available in DSpace on 2016-08-29T15:33:22Z (GMT). No. of bitstreams: 1 tese_8943_Dissertação de mestrado - Versão final.pdf: 2374812 bytes, checksum: 451a93c76906d24965d0ea838edf582f (MD5) Previous issue date: 2015-07-10 / As Redes Definidas por Software (SDN) separam os planos de dados e de controle. Embora o controlador seja logicamente centralizado, ele deve ser efetivamente distribuído para garantir alta disponibilidade. Desde a especificação OpenFlow 1.2, há novas funcionalidades que permitem aos elementos da rede se comunicarem com múltiplos controladores que podem assumir diferentes papéis -- master, slave, e equal. Entretanto, esses papéis não são suficientes para garantir resiliência no plano de controle, pois delega-se aos projetistas de redes SDN a responsabilidade por essa implementação. Neste artigo, exploramos os papéis definidos no protocolo OpenFlow no projeto de arquiteturas resilientes SDN com base em multi-controladores. Como prova de conceito uma estratégia de replicação ativa foi implementada no controlador Ryu usando o serviço OpenReplica para garantir a consistência dos estados. O protótipo foi testado com switches RouterBoards/MikroTik comerciais e no ambiente Mininet avaliando-se as latências na recuperação de falha, na migração de switches entre controladores, e de processamento de packet-in. Observamos diferentes compromissos de projeto em experimentos em ambiente real e emulado sujeitos a várias cargas nos planos de dados e de controle.

Made available in DSpace on 2016-08-29T15:33:25Z (GMT). No. of bitstreams: 1 tese_9891_Ata de Defesa.pdf: 681165 bytes, checksum: e90a96fd774c8d4b5e7a4315a623688c (MD5) Previous issue date: 2016-05-16 / Em data centers centrados em servidores estes não somente participam no processamento dos dados, mas também no encaminhamento do tráfego de rede. Uma possível topologia de interligação dos servidores em um data center é o hipercubo. Nele, o encaminhamento de pacotes é normalmente baseado em operações de XOR, que calcula qual o vizinho mais próximo do destino de forma bastante eficiente . Porém se por um lado essa simplicidade contribui para o aumento da vazão e diminuição da latência, por outro o encaminhamento só funciona caso o hipercubo esteja completo, ou seja, na inexistência de falhas de nó ou enlace. O uso de SDN e do protocolo OpenFlow pode ser uma alternativa para garantir o encaminhamento de tráfego nessas situações. Entretanto, a adoção de tabelas de encaminhamento em topologia hipercubo possui um alto custo relacionado ao grande número de entradas nessas tabelas, que crescem em escala exponencial. Nesse contexto este trabalho apresenta uma proposta, baseada na tecnologia OpenFlow, para o tratamento de falhas em hipercubos incluindo a redução do número de entradas nas tabelas de encaminhamento, com taxa de compactação logarítmica, proporcional ao número de dimensões do hipercubo.

Software Defined Networking (SDN) is an emerging architecture that is dynamic, manageable, cost-effective and adaptable, making it ideal for the high-bandwidth, dynamic nature of today’s applications. Using SDN, networks can enable a variety of concurrent, dynamically instantiated measurement tasks, that provide fine-grain visibility into network traffic by configuring Ternary Content Address Memory (TCAM) counters in hardware switches. However, TCAM memory is limited, thus the accuracy of measurement tasks depends on the number of resources devoted to them on each switch. In this thesis, we propose a solution that improves Dynamic Resource Allocation for Software-defined Measurements (DREAM), a framework with an adaptive step size search that achieves a desired level of accuracy for measurement tasks. We have enabled prediction capabilities in the framework to generate better counters configurations using previous network traffic information. We implement four estimation techniques (EWMA-based Prediction, Polynomial Curve Fitting, KMeans++ Cluster and Pseudo Linear Extrapolation) that have been tested with simulations running three types of measurement tasks (heavy hitters, hierarchical heavy hitters and traffic change detection) that show the proposed techniques improve task accuracy and tasks concurrency in DREAM. Existing traffic measurements tools usually rely on some predetermined concept of flows to collect traffic statistics. Thus, they usually have issues in adapting to changes in traffic condition and present scalability issues with respect to the number of flows and the heterogeneity of the monitoring applications. We propose an integration of the Programmable MEasurements (ProgME) paradigm, which defines a novel approach to defined measurement tasks in a programmable way using the concept of flowsets, on top of the DREAM framework. This enables better scalability for measurement tasks that deal with large amounts of traffic flows on DREAM while reducing the required number of counters allocations for the tasks.

Software-Defined Networking är ett sätt att implementera ett nätverk som helt styrs från en central plats. Målet med SDN är att vara ett flexibelt nätverk som snabbt kan förändras för att klara av dagens massiva dataströmmar. För att SDN ska kunna fungera krävs det att ett protokoll används för att sköta kommunikationen mellan den centrala kontrollpunkten och nätverksutrustningen i nätverket. OpenFlow är ett sådant protokoll. OpenFlow protokollet är väl etablerat och används i många av dagens SDN-nätverk. Ett alternativ till detta är OpFlex, ett protokoll som är nytt på dagens marknad men har stöd från en mängd stora tillverkare i datavärlden. Målet med denna rapport är att jämföra dessa protokoll både teoretisk och även praktiskt via experiment i laborationsmiljö för att identifiera likheter och skillnader mellan protokollen. För att kunna jämföra dem utfördes först en omfattande litteraturstudie där information samlades in och sammanställdes om protokollen. Efter detta sattes en laborationsmiljö upp för att testa hur protokollen arbetar. Efter experimenten sammanställdes litteraturstudien och laborationsresultaten och protokollen bedömdes på olika områden. Slutligen lyftes olika situationer fram där respektive protokoll skulle lämpas att väljas över det andra. / Software-Defined Networking is a way to implement a fully-managed network from a central location. The goal of SDN is to be a flexible network that can quickly adapt to new configurations to handle today’s massive data streams. In order for SDN to work, a protocol is required to manage communication between the central control point and the network equipment within the network. OpenFlow is such a protocol, The OpenFlow protocol is very well established and used in many of today’s SDN networks. An alternative to OpenFlow is OpFlex, a protocol that is relatively new on today’s market, but has the support of many major manufacturers within networking and computers. The aim of this thesis is to compare these protocols both theoretically and practically through experiments in a laboratory environment to identify similarities and differences between these protocols. In order to be able to compare them, a comprehensive literature study was first conducted where information about the protocols was collected and compiled. After this, a laboratory environment was set up to test how the protocols work. After the experiments, the literature study and the laboratory results were compiled the protocols were assessed in different areas. Finally, different situations were raised where each protocol would be suitable to be chosen over the other.

There has been a growing demand to manage bandwidth as the network traffic increases. Network applications such as real time video streaming, voice over IP and video conferencing in IP networks has risen rapidly over the recently and is projected to continue in the future. These applications consume a lot of bandwidth resulting in increasing pressure on the networks. In dealing with such challenges, modern networks must be designed to be application sensitive and be able to offer Quality of Service (QoS) based on application requirements. Network paradigms such as Software Defined Networking (SDN) allows for direct network programmability to change the network behavior to suit the application needs in order to provide solutions to the challenge. In this dissertation, the objective is to research if SDN can provide scalable QoS requirements to a set of dynamic traffic flows. Methods are implemented to attain scalable bandwidth management to provide high QoS with SDN. Differentiated Services Code Point (DSCP) values and DSCP remarking with Meters are used to implement high QoS requirements such that bandwidth guarantee is provided to a selected set of traffic flows. The theoretical methodology is implemented for achieving QoS, experiments are conducted to validate and illustrate that QoS can be implemented in SDN, but it is unable to implement High QoS due to the lack of implementation for Meters with DSCP remarking. The research work presented in this dissertation aims at the identification and addressing the critical aspects related to the SDN based QoS provisioning using flow aggregation techniques. Several tests and demonstrations will be conducted by utilizing virtualization methods. The tests are aimed at supporting the proposed ideas and aims at creating an improved understanding of the practical SDN use cases and the challenges that emerge in virtualized environments. DiffServ Assured Forwarding is chosen as a QoS architecture for implementation. The bandwidth management scalability in SDN is proved based on throughput analysis by considering two conditions i.e 1) Per-flow QoS operation and 2) QoS by using DiffServ operation in the SDN environment with Ryu controller. The result shows that better performance QoS and bandwidth management is achieved using the QoS by DiffServ operation in SDN rather than the per-flow QoS operation.

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The concept of Software Defined Networking (SDN) may be a way to face the fast growing computer network infrastructure with its demands and requirements. The concept is attracting the interest of enterprises to expand their respective network infrastructures, but one has to consider the impacts of migrating from an existing network infrastructure to an SDN network. One way that could minimize the impacts is to proceed a soft migration from a traditional IP network to SDN, creating what is so called a heterogeneous network. Instead of fully replacing the network infrastructure and face the impacts of it, the idea of the soft migration is to replace a part of it with an environment of SDN and examine the performance of it. This thesis work will analyze the performance of a network consisting of a traditional IP network combined with SDN. It is essential during this work to identify the differences in performance when having a heterogeneous network in comparison with having a dedicated traditional IP network. Therefore, the questions that will be addressed during this thesis work is to examine how such a heterogeneous network can be designed and measure the performance of it in terms of throughput, jitter and packet losses. By the method of experimentation and the studying of related works of the SDN fundamentals, we hope to achieve our goals with this thesis work, to give us and the reader a clearer insight.

Mobile Ad-hoc Cloud offers users the capability to offload intensive tasks on a cloud composed of voluntary mobile devices. Due to the availability of these devices in the proximity, intensive tasks can be processed locally. In addition, the literature referred to in the text, distinguishes a specific class of application to be well addressed when processed at the user level. However, due to lack of commitment, mobility, and unpredictability of the mobile devices, providing a rich ad-hoc cloud service is challenging. Furthermore, the resource availability of these devices impacts the service offered to the requester. As a result, this thesis aims to address the challenges mentioned above. With the support of Multi-Access Edge Computing, a mobile ad-hoc Infrastructure as a Service composition framework is proposed. An ad-hoc application server is designed to operate over the MEC platform to compose and manage the mobile ad-hoc cloud. The server uses the information provided by the MEC services to compose volunteer resources for a given request. As well, a heuristic approach for a multi-dimensional bin packing technique is considered, while extending the Euclidean distance for sub-tasks selection. In addition, to address the lack of resource availability, an architecture for MAC using SDN is proposed. The logically centralized controller works with the application server to migrate requests seamlessly from one region to another. Inspired by the benefits of the MEC, a mobility mechanism is introduced to address the movement of the participants. Finally, based on the evaluation, it was observed that the proposed MAC framework not only provided better use of resources but also provided a consisted and scalable service.

The software integration with new network architectures via Software-Defined Networking (SDN) axis appears to be a major evolution of networks. While this paradigm was primarily developed for easy network setup, its ability to integrate services has also to be considered. Thus, the mobility service for which solutions have been proposed in conventional architectures by defining standardized protocols should be rethought in terms of SDN service. Mobile devices might use or move in SDN network. In this thesis, we proposed a new mobility management approach which called "SDN-Mobility" and has shown that SDN can be implemented without IP mobility protocol for providing mobility like as Proxy Mobile IPv6 (PMIPv6) that is the solution adopted by 3GPP, with some performance gain. However, PMIPv6 and SDN-Mobility have some packets loss during Mobile Node (MN) handover. Thus, in this thesis, we proposed a new paradigm based on caching function to improve the quality of transfer during handover. Caching policy cooperates with SDN controller for automatic buffering of the data during the handover. We proposed two caching policies that are compared through a performance analysis regarding the quality of transfer for the user and for the operator. This thesis also presented that SDN-Mobility with caching policy can be applied easily for mobility management in heterogeneous network architectures able to integrate the future Internet based on the Information-Centric Networking (ICN).