Software-Defined Networking: A Comprehensive Survey

peer reviewedThe Internet has led to the creation of a digital society, where (almost) everything is connected and is accessible from anywhere. However, despite their widespread adoption, traditional IP networks are complex and very hard to manage. It is both difficult to configure the network according to predefined policies, and to reconfigure it to respond to faults, load, and changes. To make matters even more difficult, current networks are also vertically integrated: the control and data planes are bundled together. Software-defined networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network's control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns, introduced between the definition of network policies, their implementation in switching hardware, and the forwarding of traffic, is key to the desired flexibility: by breaking the network control problem into tractable pieces, SDN makes it easier to create and introduce new abstractions in networking, simplifying network management and facilitating network evolution. In this paper, we present a comprehensive survey on SDN. We start by introducing the motivation for SDN, explain its main concepts and how it differs from traditional networking, its roots, and the standardization activities regarding this novel paradigm. Next, we present the key building blocks of an SDN infrastructure using a bottom-up, layered approach. We provide an in-depth analysis of the hardware infrastructure, southbound and northbound application programming interfaces (APIs), network virtualization layers, network operating systems (SDN controllers), network programming languages, and network applications. We also look at cross-layer problems such as debugging and troubleshooting. In an effort to anticipate the future evolution of this - ew paradigm, we discuss the main ongoing research efforts and challenges of SDN. In particular, we address the design of switches and control platforms—with a focus on aspects such as resiliency, scalability, performance, security, and dependability—as well as new opportunities for carrier transport networks and cloud providers. Last but not least, we analyze the position of SDN as a key enabler of a software-defined environment

Enhancing programmability for adaptive resource management in next generation data centre networks

Recently, Data Centre (DC) infrastructures have been growing rapidly to support a wide range of emerging services, and provide the underlying connectivity and compute resources that facilitate the "*-as-a-Service" model. This has led to the deployment of a multitude of services multiplexed over few, very large-scale centralised infrastructures. In order to cope with the ebb and flow of users, services and traffic, infrastructures have been provisioned for peak-demand resulting in the average utilisation of resources to be low. This overprovisionning has been further motivated by the complexity in predicting traffic demands over diverse timescales and the stringent economic impact of outages. At the same time, the emergence of Software Defined Networking (SDN), is offering new means to monitor and manage the network infrastructure to address this underutilisation. This dissertation aims to show how measurement-based resource management can improve performance and resource utilisation by adaptively tuning the infrastructure to the changing operating conditions. To achieve this dynamicity, the infrastructure must be able to centrally monitor, notify and react based on the current operating state, from per-packet dynamics to longstanding traffic trends and topological changes. However, the management and orchestration abilities of current SDN realisations is too limiting and must evolve for next generation networks. The current focus has been on logically centralising the routing and forwarding decisions. However, in order to achieve the necessary fine-grained insight, the data plane of the individual device must be programmable to collect and disseminate the metrics of interest. The results of this work demonstrates that a logically centralised controller can dynamically collect and measure network operating metrics to subsequently compute and disseminate fine-tuned environment-specific settings. They show how this approach can prevent TCP throughput incast collapse and improve TCP performance by an order of magnitude for partition-aggregate traffic patterns. Futhermore, the paradigm is generalised to show the benefits for other services widely used in DCs such as, e.g, routing, telemetry, and security

Towards Software-Defined Protection, Automation, and Control in Power Systems: Concepts, State of the Art, and Future Challenges

Nowadays, power systems’ Protection, Automation, and Control (PAC) functionalities are often deployed in different constrained devices (Intelligent Electronic Devices) following a coupled hardware/software design. However, with the increase in distributed energy resources, more customized controllers will be required. These devices have high operational and deployment costs with long development, testing, and complex upgrade cycles. Addressing these challenges requires that a ’revolution’ in power system PAC design takes place. Decoupling from hardware-dependent implementations by virtualizing the functionalities facilitates the transition from a traditional power grid into a software-defined smart grid. This article presents a survey of recent literature on software-defined PAC for power systems, covering the concepts, main academic works, industrial proof of concepts, and the latest standardization efforts in this rising area. Finally, we summarize the expected future technical, industrial, and standardization challenges and open research problems. It was observed that software-defined PAC systems have a promising potential that can be leveraged for future PAC and smart grid developments. Moreover, standardizations in virtual IED software development and deployments, configuration tools, performance benchmarking, and compliance testing using a dynamic, agile approach assuring interoperability are critical enablers. © 2022 by the authors

Special Topics in Information Technology

This open access book presents thirteen outstanding doctoral dissertations in Information Technology from the Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy. Information Technology has always been highly interdisciplinary, as many aspects have to be considered in IT systems. The doctoral studies program in IT at Politecnico di Milano emphasizes this interdisciplinary nature, which is becoming more and more important in recent technological advances, in collaborative projects, and in the education of young researchers. Accordingly, the focus of advanced research is on pursuing a rigorous approach to specific research topics starting from a broad background in various areas of Information Technology, especially Computer Science and Engineering, Electronics, Systems and Control, and Telecommunications. Each year, more than 50 PhDs graduate from the program. This book gathers the outcomes of the thirteen best theses defended in 2019-20 and selected for the IT PhD Award. Each of the authors provides a chapter summarizing his/her findings, including an introduction, description of methods, main achievements and future work on the topic. Hence, the book provides a cutting-edge overview of the latest research trends in Information Technology at Politecnico di Milano, presented in an easy-to-read format that will also appeal to non-specialists

MACSAD: Sistema de Compilador Multi-Arquitetura para Planos de Dados Abstratos

Orientador: Christian Rodolfo Esteve RothenbergTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Redes Definidas por Software (Software-Defined Networking - SDN) almejam um plano de dados programável, além de planos de controle e aplicação flexíveis e escaláveis. Apesar de ter recebido menor atenção quando comparado aos aspectos dos planos de controle e aplicação, o plano de dados concerne uma peça chave nos enigmas de SDN. Nós contemplamos um plano de dados flexível apresentando as características, nomeadas, Programabilidade, Portabilidade, Desempenho e Escalabilidade (Programmability, Portability, Performance, and Scalability - 3PS) como diferentes aspectos de flexibilidade. Enquanto os aspectos de Programabilidade e Portabilidade focam na arquitetura e projeto do plano de dados, Desempenho e Escalabilidade aparecem durante a avaliação do mesmo. Estendemos o foco da evolução do plano de dados de Programabilidade da escola de pensamento SDN para incluir Portabilidade como aspecto de flexibilidade. O plano de dados programável confirma a natureza independente do protocolo, enquanto a Portabilidade atende aos requisitos de arquitetura múltipla do projeto do plano de dados. A linguagem P4, uma nova entrante, sendo uma linguagem de programação de alto nível independente do protocolo e independente do alvo, é capaz de levar a evolução do plano de dados ao próximo nível, desbloqueando as facetas desejadas da flexibilidade do plano de dados. Para trazer esse nível necessário de flexibilidade para um plano de dados, é necessário um sistema de compilador com várias arquiteturas que possa compilar um programa P4 em conformidade com o protocolo e a natureza de independência de destino de P4; No entanto, essa solução de sistema de compilador unificado é o que nos falta. A principal contribuição desta tese, a proposta do Sistema de Compiladores de Arquitetura Múltipla para Planos de Dados (Multi-Architecture Compiler System for Abstract Dataplanes - MACSAD), é um esforço para preencher a lacuna estendendo a abordagem Top-Down de P4 em direção à programabilidade com a abordagem Bottom-Up do OpenDataPlane (ODP) em direção à independência de destino com suas APIs de baixo nível, mas de plataforma cruzada (HW & SW). Reforçamos as contribuições desta tese incluindo aspectos de Desempenho e Escalabilidade da flexibilidade também como parte de nossa avaliação do MACSAD em múltiplos cenários realistasAbstract: Software-Defined Networking (SDN) strives for programmable data plane, yet flexible and scalable control and application planes. Despite having received less attention compared to control and application aspects of SDN, data planes are a critical piece of the SDN puzzle. We envision a flexible data plane showing characteristics, namely, Programmability, Portability, Performance, and Scalability (3PS) as different aspects of flexibility. While Programmability & Portability aspects focus on the architecture and design of the data plane, Performance & Scalability appears during the evaluation of it. We extend the focus of data plane evolution from Programmability from SDN school of thought to include Portability aspect of flexibility. Programmable data plane confirms to protocol-independent nature, whereas Portability addresses multi-architecture requirements of data plane design. P4 language, a new entrant, being a protocol-independent and target-independent high-level programming language is capable to take data plane evolution to the next level by unlocking the desired facets of data plane flexibility. To bring this required level of flexibility to a data plane, a multi-architecture compiler system is necessary which can compile P4 program conforming to protocol & target independence nature of P4; However, such a unified compiler system solution is what we lack of. The main contribution of this thesis, the MACSAD proposal, is an effort to fill the gap by extending the Top-Down approach of P4 towards programmability with Bottom-Up approach of OpenDataPlane (ODP) towards target-independence with its low-level but cross-platform (HW & SW) APIs. We strengthen the contributions of this thesis by including Performance, and Scalability aspects of flexibility too as part of our evaluation of MACSAD in multiple realistic scenariosDoutoradoEngenharia de ComputaçãoDoutor em Engenharia Elétric

Machine Learning-based Orchestration Solutions for Future Slicing-Enabled Mobile Networks

The fifth generation mobile networks (5G) will incorporate novel technologies such as network programmability and virtualization enabled by Software-Defined Networking (SDN) and Network Function Virtualization (NFV) paradigms, which have recently attracted major interest from both academic and industrial stakeholders. Building on these concepts, Network Slicing raised as the main driver of a novel business model where mobile operators may open, i.e., “slice”, their infrastructure to new business players and offer independent, isolated and self-contained sets of network functions and physical/virtual resources tailored to specific services requirements. While Network Slicing has the potential to increase the revenue sources of service providers, it involves a number of technical challenges that must be carefully addressed. End-to-end (E2E) network slices encompass time and spectrum resources in the radio access network (RAN), transport resources on the fronthauling/backhauling links, and computing and storage resources at core and edge data centers. Additionally, the vertical service requirements’ heterogeneity (e.g., high throughput, low latency, high reliability) exacerbates the need for novel orchestration solutions able to manage end-to-end network slice resources across different domains, while satisfying stringent service level agreements and specific traffic requirements. An end-to-end network slicing orchestration solution shall i) admit network slice requests such that the overall system revenues are maximized, ii) provide the required resources across different network domains to fulfill the Service Level Agreements (SLAs) iii) dynamically adapt the resource allocation based on the real-time traffic load, endusers’ mobility and instantaneous wireless channel statistics. Certainly, a mobile network represents a fast-changing scenario characterized by complex spatio-temporal relationship connecting end-users’ traffic demand with social activities and economy. Legacy models that aim at providing dynamic resource allocation based on traditional traffic demand forecasting techniques fail to capture these important aspects. To close this gap, machine learning-aided solutions are quickly arising as promising technologies to sustain, in a scalable manner, the set of operations required by the network slicing context. How to implement such resource allocation schemes among slices, while trying to make the most efficient use of the networking resources composing the mobile infrastructure, are key problems underlying the network slicing paradigm, which will be addressed in this thesis

Computer Aided Verification

The open access two-volume set LNCS 12224 and 12225 constitutes the refereed proceedings of the 32st International Conference on Computer Aided Verification, CAV 2020, held in Los Angeles, CA, USA, in July 2020.* The 43 full papers presented together with 18 tool papers and 4 case studies, were carefully reviewed and selected from 240 submissions. The papers were organized in the following topical sections: Part I: AI verification; blockchain and Security; Concurrency; hardware verification and decision procedures; and hybrid and dynamic systems. Part II: model checking; software verification; stochastic systems; and synthesis. *The conference was held virtually due to the COVID-19 pandemic