On software-defined networking and the design of SDN controllers

© 2015 IEEE. Software-Defined Networking (SDN) has emerged as a networking paradigm that can remove the limitations of current network infrastructures by separating the control plane from the data forwarding plane. The implications include: the underlying network state and decision making capability are centralized; programmability is provided on the control plane; the operation at the forwarding plane is simplified; and the underlying network infrastructure is abstracted and presented to the applications. This paper discusses and exposes the details of the design of a common SDN controller based on our study of many controllers. The emphasis is on interfaces as they are essential for evolving the scope of SDN in supporting applications with different network resources requirements. In particular, the paper review and compare the design of the three controllers: Beacon, OpenDaylight, and Open Networking Operation System

Towards a software defined network based multi-domain architecture for the internet of things

The current communication networks are heterogeneous, with a diversity of devices and services that challenge traditional networks, making it difficult to meet quality of service (QoS) requirements. With the advent of software-defined networks (SDN), new tools have emerged to design more flexible networks. SDN offers centralized management for data streams in distributed sensor networks. Thus, the main goal of this dissertation is to investigate a solution that meets the QoS requirements of traffic originating on Internet of Things (IoT) devices. This traffic is transmitted to the Internet in a distributed system with multiple SDN controllers. To achieve the goal, we designed a multi-controller network topology, each managed by its controller. Communication between the domains is done via an SDN traffic domain with the Open Network Operating System (ONOS) controller SDN-IP application. We also emulated a network to test QoS through OpenvSwitch queues. The goal is to create traffic priorities in a network with traditional and simulated IoT devices. According to our tests, we have been able to ensure the SDN inter-domain communication and have proven that our proposal is reactive to a topology failure. In the QoS scenario we have shown that through the insertion of OpenFlow rules, we are able to prioritize traffic and provide guarantees of quality of service. This proves that our proposal is promising for use in scenarios with multiple administrative domains.As redes atuais de comunicação são heterogéneas, com uma diversidade de dispositivos e serviços, que desafiam as redes tradicionais, dificultando a satisfação dos requisitos de qualidade de serviço (QoS). Com o advento das Redes Definidas por Software (SDN), novas ferramentas surgiram para projetar redes mais flexíveis. O SDN oferece uma gestão centralizada para os fluxos de dados em redes distribuídas de sensores. Assim, o principal objetivo desta dissertação é de investigar uma solução que cumpra os requisitos de QoS do tráfego originado em dispositivos de Internet das coisas (IoT). Este tráfego é transmitido para a Internet, num sistema distribuído com múltiplos controladores SDN. Para atingir o objetivo, projetamos uma topologia de rede com múltiplos domínios, cada um gerido pelo seu controlador. A comunicação entre os domínios, é feita através dum domínio de trânsito SDN com a aplicação SDN-IP do controlador Sistema Operativo de Rede Aberta (ONOS). Emulamos também uma rede para testar a QoS através de filas de espera do OpenvSwitch. O objetivo é criar prioridades de tráfego numa rede com dispositivos tradicionais e de IoT simulados. De acordo com os testes realizados, conseguimos garantir a comunicação entre domínios SDN e comprovamos que a nossa proposta é reativa a uma falha na topologia. No cenário do QoS demostramos que, através da inserção de regras OpenFlow, conseguimos priorizar o tráfego e oferecer garantias de qualidade de serviço. Desta forma comprovamos que a nossa proposta é promissora para ser utilizada em cenários com múltiplos domínios administrativos

The Role of Inter-Controller Traffic for Placement of Distributed SDN Controllers

We consider a distributed Software Defined Networking (SDN) architecture adopting a cluster of multiple controllers to improve network performance and reliability. Besides the Openflow control traffic exchanged between controllers and switches, we focus on the control traffic exchanged among the controllers in the cluster, needed to run coordination and consensus algorithms to keep the controllers synchronized. We estimate the effect of the inter-controller communications on the reaction time perceived by the switches depending on the data-ownership model adopted in the cluster. The model is accurately validated in an operational Software Defined WAN (SDWAN). We advocate a careful placement of the controllers, that should take into account both the above kinds of control traffic. We evaluate, for some real ISP network topologies, the delay tradeoffs for the controllers placement problem and we propose a novel evolutionary algorithm to find the corresponding Pareto frontier. Our work provides novel quantitative tools to optimize the planning and the design of the network supporting the control plane of SDN networks, especially when the network is very large and in-band control plane is adopted. We also show that for operational distributed controllers (e.g. OpenDaylight and ONOS), the location of the controller which acts as a leader in the consensus algorithm has a strong impact on the reactivity perceived by switches.Comment: 14 page