An evolvable, scalable, and resilient control channel for software defined wireless access networks

AbstractThis paper presents a novel multipath communication-based OpenFlow channel for Software Defined Wireless Access Networks (SDWANs), namely mOpenFlow. The advantageous features of mOpenFlow include the following: (i) resilience and scalability in wireless environments, (ii) evolvability of the existing access networks and the OpenFlow standard, (iii) a novel network calculus-based model for performance analysis of mOpenFlow. By leveraging the multipath communication for conveying OpenFlow traffic, mOpenFlow enhances both robustness (i.e., resilience) and throughput (i.e., scalability) of the control channel. To achieve the evolvability, mOpenFlow adopts the multipath transport control protocol, which conforms to SDWANs and the OpenFlow standard. We evaluate mOpenFlow in an emulated SDWAN in relation to the standard channel. The results show that mOpenFlow outperforms the standard channel, both in terms of robustness and scalability. Additionally, the numerical results indicate that the model provides a fast and reliable way for analyzing the end-to-end delay on mOpenFlow

Network Slicing Landscape: A holistic architectural approach, orchestration and management with applicability in mobile and fixed networks and clouds

Tutorial at IEEE NetSoft2018 - 29th June 2018 Montreal Abstract: A holistic architectural approach, orchestration and management with applicability in mobile and fixed networks and clouds Topics: Key Slicing concepts and history Slicing Key Characteristics & Usage scenarios & Value Chain Multi-Domain Network Function Virtualisation Review of Research projects and results in network and cloud slicing Open Source Orchestrators Standard Organization activities: NGMN, ITU-T, ONF, 3GPP, ETSI, BBF, IETF Industrial perspective on Network Slicing Review of industry Use Cases Network Slicing Challenges Concluding remarks of Network Slicing Acknowledgements & Reference

Reliable Packet Streams with Multipath Network Coding

With increasing computational capabilities and advances in robotics, technology is at the verge of the next industrial revolution. An growing number of tasks can be performed by artificial intelligence and agile robots. This impacts almost every part of the economy, including agriculture, transportation, industrial manufacturing and even social interactions. In all applications of automated machines, communication is a critical component to enable cooperation between machines and exchange of sensor and control signals. The mobility and scale at which these automated machines are deployed also challenges todays communication systems. These complex cyber-physical systems consisting of up to hundreds of mobile machines require highly reliable connectivity to operate safely and efficiently. Current automation systems use wired communication to guarantee low latency connectivity. But wired connections cannot be used to connect mobile robots and are also problematic to deploy at scale. Therefore, wireless connectivity is a necessity. On the other hand, it is subject to many external influences and cannot reach the same level of reliability as the wired communication systems. This thesis aims to address this problem by proposing methods to combine multiple unreliable wireless connections to a stable channel. The foundation for this work is Caterpillar Random Linear Network Coding (CRLNC), a new variant of network code designed to achieve low latency. CRLNC performs similar to block codes in recovery of lost packets, but with a significantly decreased latency. CRLNC with Feedback (CRLNC-FB) integrates a Selective-Repeat ARQ (SR-ARQ) to optimize the tradeoff between delay and throughput of reliable communication. The proposed protocol allows to slightly increase the overhead to reduce the packet delay at the receiver. With CRLNC, delay can be reduced by more than 50 % with only a 10 % reduction in throughput. Finally, CRLNC is combined with a statistical multipath scheduler to optimize the reliability and service availability in wireless network with multiple unreliable paths. This multipath CRLNC scheme improves the reliability of a fixed-rate packet stream by 10 % in a system model based on real-world measurements of LTE and WiFi. All the proposed protocols have been implemented in the software library NCKernel. With NCKernel, these protocols could be evaluated in simulated and emulated networks, and were also deployed in several real-world testbeds and demonstrators.:Abstract 2 Acknowledgements 6 1 Introduction 7 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2 Use Cases and Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.3 Opportunities of Multipath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.4 Contribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2 State of the Art of Multipath Communication 19 2.1 Physical Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2 Data Link Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.3 Network Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.4 Transport Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2.5 Application Layer and Session Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.6 Research Gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3 NCKernel: Network Coding Protocol Framework 27 3.1 Theory that matters! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.3 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.3.1 Socket Buffers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.3.2 En-/Re-/Decoder API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.3.3 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.3.4 Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.3.5 Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3.4 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3.5 Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4 Low-Latency Network Coding 35 4.1 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4.2 Random Linear Network Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 4.3 Low Latency Network Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 4.4 CRLNC: Caterpillar Random Linear Network Coding . . . . . . . . . . . . . . . . . . 38 4.4.1 Encoding and Packet Format . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 4.4.2 Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.4.3 Computational Complexity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.5 Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.5.1 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.5.2 Simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4.5.3 Packet Loss Probability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 4.5.4 Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4.5.5 Window Size Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 4.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 5 Delay-Throughput Tradeoff 55 5.1 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.2 Network Coding with ARQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.3 CRLNC-FB: CRLNC with Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5.3.1 Encoding and Packet Format . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.3.2 Decoding and Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.3.3 Retransmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.4 Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 5.4.1 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 5.4.2 Simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 5.4.3 Systematic Retransmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 5.4.4 Coded Packet Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.4.5 Comparison with other Protocols . . . . . . . . . . . . . . . . . . . . . . . . 67 5.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 6 Multipath for Reliable Low-Latency Packet Streams 73 6.1 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 6.2 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 6.3 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 6.3.1 Traffic Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 6.3.2 Network Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 6.3.3 Channel Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 6.3.4 Reliability Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 6.4 Multipath CRLNC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 6.4.1 Window Size for Heterogeneous Paths . . . . . . . . . . . . . . . . . . . . . 77 6.4.2 Packet Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 6.5 Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 6.5.1 Simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 6.5.2 Preliminary Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 6.5.3 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 6.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 7 Conclusion 94 7.1 Results and Contribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 7.2 Future Research Topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Acronyms 99 Publications 101 Bibliography 10

Self-organized backpressure routing for the wireless mesh backhaul of small cells

The ever increasing demand for wireless data services has given a starring role to dense small cell (SC) deployments for mobile networks, as increasing frequency re-use by reducing cell size has historically been the most effective and simple way to increase capacity. Such densification entails challenges at the Transport Network Layer (TNL), which carries packets throughout the network, since hard-wired deployments of small cells prove to be cost-unfeasible and inflexible in some scenarios. The goal of this thesis is, precisely, to provide cost-effective and dynamic solutions for the TNL that drastically improve the performance of dense and semi-planned SC deployments. One approach to decrease costs and augment the dynamicity at the TNL is the creation of a wireless mesh backhaul amongst SCs to carry control and data plane traffic towards/from the core network. Unfortunately, these lowcost SC deployments preclude the use of current TNL routing approaches such as Multiprotocol Label Switching Traffic Profile (MPLS-TP), which was originally designed for hard-wired SC deployments. In particular, one of the main problems is that these schemes are unable to provide an even network resource consumption, which in wireless environments can lead to a substantial degradation of key network performance metrics for Mobile Network Operators. The equivalent of distributing load across resources in SC deployments is making better use of available paths, and so exploiting the capacity offered by the wireless mesh backhaul formed amongst SCs. To tackle such uneven consumption of network resources, this thesis presents the design, implementation, and extensive evaluation of a self-organized backpressure routing protocol explicitly designed for the wireless mesh backhaul formed amongst the wireless links of SCs. Whilst backpressure routing in theory promises throughput optimality, its implementation complexity introduces several concerns, such as scalability, large end-to-end latencies, and centralization of all the network state. To address these issues, we present a throughput suboptimal yet scalable, decentralized, low-overhead, and low-complexity backpressure routing scheme. More specifically, the contributions in this thesis can be summarized as follows: We formulate the routing problem for the wireless mesh backhaul from a stochastic network optimization perspective, and solve the network optimization problem using the Lyapunov-driftplus-penalty method. The Lyapunov drift refers to the difference of queue backlogs in the network between different time instants, whereas the penalty refers to the routing cost incurred by some network utility parameter to optimize. In our case, this parameter is based on minimizing the length of the path taken by packets to reach their intended destination. Rather than building routing tables, we leverage geolocation information as a key component to complement the minimization of the Lyapunov drift in a decentralized way. In fact, we observed that the combination of both components helps to mitigate backpressure limitations (e.g., scalability,centralization, and large end-to-end latencies). The drift-plus-penalty method uses a tunable optimization parameter that weight the relative importance of queue drift and routing cost. We find evidence that, in fact, this optimization parameter impacts the overall network performance. In light of this observation, we propose a self-organized controller based on locally available information and in the current packet being routed to tune such an optimization parameter under dynamic traffic demands. Thus, the goal of this heuristically built controller is to maintain the best trade-off between the Lyapunov drift and the penalty function to take into account the dynamic nature of semi-planned SC deployments. We propose low complexity heuristics to address problems that appear under different wireless mesh backhaul scenarios and conditions..

An outright open source approach for simple and pragmatic internet eXchange

L'Internet, le réseaux des réseaux, est indispensable à notre vie moderne et mondialisée et en tant que ressource publique il repose sur l'inter opérabilité et la confiance. Les logiciels libres et open source jouent un rôle majeur pour son développement. Les points d'échange Internet (IXP) où tous les opérateurs de type et de taille différents peuvent s'échanger du trafic sont essentiels en tant que lieux d'échange neutres et indépendants. Le service fondamental offert par un IXP est une fabrique de commutation de niveau 2 partagée. Aujourd'hui les IXP sont obligés d'utiliser des technologies propriétaires pour leur fabrique de commutations. Bien qu'une fabrique de commutations de niveau 2 se doit d'être une fonctionnalité de base, les solutions actuelles ne répondent pas correctement aux exigences des IXPs. Cette situation est principalement dûe au fait que les plans de contrôle et de données sont intriqués sans possibilités de programmer finement le plan de commutation. Avant toute mise en œuvre, il est primordial de tester chaque équipement afin de vérifier qu'il répond aux attentes mais les solutions de tests permettant de valider les équipements réseaux sont toutes non open source, commerciales et ne répondent pas aux besoins techniques d'indépendance et de neutralité. Le "Software Defined Networking" (SDN), nouveau paradigme découplant les plans de contrôle et de données utilise le protocole OpenFlow qui permet de programmer le plan de commutation Ethernet haute performance. Contrairement à tous les projets de recherches qui centralisent la totalité du plan de contrôle au dessus d'OpenFlow, altérant la stabilité des échanges, nous proposons d'utiliser OpenFlow pour gérer le plan de contrôle spécifique à la fabrique de commutation. L'objectif principal de cette thèse est de proposer "Umbrella", fabrique de commutation simple et pragmatique répondant à toutes les exigences des IXPs et en premier lieu à la garantie d'indépendance et de neutralité des échanges. Dans la première partie, nous présentons l'architecture "Umbrella" en détail avec l'ensemble des tests et validations démontrant la claire séparation du plan de contrôle et du plan de données pour augmenter la robustesse, la flexibilité et la fiabilité des IXPs. Pour une exigence d'autonomie des tests nécessaires pour les IXPs permettant l'examen de la mise en œuvre d'Umbrella et sa validation, nous avons développé l'"Open Source Network Tester" (OSNT), un système entièrement open source "hardware" de génération et de capture de trafic. OSNT est le socle pour l"OpenFLow Operations Per Second Turbo" (OFLOPS Turbo), la plate-forme d'évaluation de commutation OpenFlow. Le dernier chapitre présente le déploiement de l'architecture "Umbrella" en production sur un point d'échange régional. Les outils de test que nous avons développés ont été utilisés pour vérifier les équipements déployés en production. Ce point d'échange, stable depuis maintenant un an, est entièrement géré et contrôlé par une seule application Web remplaçant tous les systèmes complexes et propriétaires de gestion utilisés précédemment.In almost everything we do, we use the Internet. The Internet is indispensable for our today's lifestyle and to our globalized financial economy. The global Internet traffic is growing exponentially. IXPs are the heart of Internet. They are highly valuable for the Internet as neutral exchange places where all type and size of autonomous systems can "peer" together. The IXPs traffic explode. The 2013 global Internet traffic is equivalent with the largest european IXP today. The fundamental service offer by IXP is a shared layer2 switching fabric. Although it seems a basic functionality, today solutions never address their basic requirements properly. Today networks solutions are inflexible as proprietary closed implementation of a distributed control plane tight together with the data plane. Actual network functions are unmanageable and have no flexibility. We can understand how IXPs operators are desperate reading the EURO-IX "whishlist" of the requirements who need to be implemented in core Ethernet switching equipments. The network vendor solutions for IXPs based on MPLS are imperfect readjustment. SDN is an emerging paradigm decoupling the control and data planes, on opening high performance forwarding plane with OpenFlow. The aims of this thesis is to propose an IXP pragmatic Openflow switching fabric, addressing the critical requirements and bringing more flexibility. Transparency is better for neutrality. IXPs needs a straightforward more transparent layer2 fabric where IXP participants can exchange independently their traffic. Few SDN solutions have been presented already but all of them are proposing fuzzy layer2 and 3 separation. For a better stability not all control planes functions can be decoupled from the data plane. As other goal statement, networking testing tools are essential for qualifying networking equipment. Most of them are software based and enable to perform at high speed with accuracy. Moreover network hardware monitoring and testing being critical for computer networks, current solutions are both extremely expensive and inflexible. The experience in deploying Openflow in production networks has highlight so far significant limitations in the support of the protocol by hardware switches. We presents Umbrella, a new SDN-enabled IXP fabric architecture, that aims at strengthening the separation of control and data plane to increase both robustness, flexibility and reliability of the exchange. Umbrella abolish broadcasting with a pseudo wire and segment routing approach. We demonstrated for an IXP fabric not all the control plane can be decoupled from the date plane. We demonstrate Umbrella can scale and recycle legacy non OpenFlow core switch to reduce migration cost. Into the testing tools lacuna we launch the Open Source Network Tester (OSNT), a fully open-source traffic generator and capture system. Additionally, our approach has demonstrated lower-cost than comparable commercial systems while achieving comparable levels of precision and accuracy; all within an open-source framework extensible with new features to support new applications, while permitting validation and review of the implementation. And we presents the integration of OpenFLow Operations Per Second (OFLOPS), an OpenFlow switch evaluation platform, with the OSNT platform, a hardware-accelerated traffic generation and capturing platform. What is better justification than a real deployment ? We demonstrated the real flexibility and benefit of the Umbrella architecture persuading ten Internet Operators to migrate the entire Toulouse IXP. The hardware testing tools we have developed have been used to qualify the hardware who have been deployed in production. The TouIX is running stable from a year. It is fully managed and monitored through a single web application removing all the legacy complex management systems

Sistema de encaminhamento resiliente para serviços críticos sobre redes públicas móveis

Dissertação para obtenção do Grau de Mestre em Engenharia Informática e de ComputadoresExistem cada vez mais serviços críticos assentes sobre ligações móveis fornecidas por operadores públicos. No entanto, estas ligações não oferecem, muitas vezes, Service Level Agreement (SLA) alinhados com a criticidade do serviço que as utiliza. O 5G veio oferecer nativamente mecanismos que permitem fornecer este tipo de garantias a um serviço e aplicação. No entanto, isto carece de negociação com o operador em causa, com custos não negligenciáveis. Adicionalmente, em situações de falha do operador, a resiliência continua a não estar assegurada. Assim, neste trabalho pretende-se desenvolver, sobre um sistema operativo de código aberto, um sistema de comunicação (gateway) que permita o encaminhamento de flows de pacotes, com elevada resiliência e segurança, através de múltiplas ligações WAN baseadas em redes públicas móveis, com a gateway estática ou em movimento. Identificam-se como grandes resultados para este trabalho: 1) A integração, através de um stack de software, num sistema operativo baseado em Linux, da capacidade de agregação automatizada de diferentes ligações WAN de forma transparente para as aplicações através de um canal seguro; e, 2) A avaliação da Qualidade de Serviço oferecida, para determinar quais as melhores ligações a usar utilizando para tal as Application Programming Interface (API) existentes no Kernel de um sistema operativo Linux.The number of critical services based on mobile connections provided by public operators has been rising significantly. However, these connections often do not offer Service Level Agreements (SLAs) in line with the criticality of the service that uses them. 5G has natively offered mechanisms that allow this type of guarantee to be provided to a service and application. Nonetheless, this requires negotiation with the operator, with non-negligible costs, and in situations of operator failure, resilience is not guaranteed. Thus, the present work aims to develop a gateway based on an open-source operating system that allows packet flow forwarding, with high resilience and security, through multiple WAN connections based on public mobile networks, with a static or a moving terminal. The main goals for this work are: 1) The integration, through a software stack, in a Linux-based OS, of the automated aggregation capacity of different WAN connections transparently to the applications through a secure channel; and, 2) The evaluation of the Quality of Service offered, in order to establish the best connections using the Application Programming Interfaces (APIs) existing in the Kernel of a Linux operating system.info:eu-repo/semantics/publishedVersio

Automating Computational Placement for the Internet of Things

PhD ThesisThe PATH2iot platform presents a new approach to distributed data analytics for Internet of Things applications. It automatically partitions and deploys stream-processing computations over the available infrastructure (e.g. sensors, field gateways, clouds and the networks that connect them) so as to meet non-functional requirements including network limitations and energy. To enable this, the user gives a high-level declarative description of the computation as a set of Event Processing Language queries. These are compiled, optimised, and partitioned to meet the non-functional requirements using a combination of distributed query processing techniques that optimise the computation, and cost models that enable PATH2iot to select the best deployment plan given the non-functional requirements. This thesis describes the resulting PATH2iot system, illustrated with two real-world use cases. First, a digital healthcare analytics system in which sensor battery life is the main non-functional requirement to be optimized. This shows that the tool can automatically partition and distribute the computation across a healthcare wearable, a mobile phone and the cloud - increasing the battery life of the smart watch by 453% when compared to other possible allocations. The energy cost of sending messages over a wireless network is a key component of the cost model, and we show how this can be modelled. Furthermore, the uncertainty of the model is addressed with two alternative approaches: one frequentist and one Bayesian The second use case is one in which an acoustic data analytics for transport monitoring is automatically distributed so as enable it to run over a low-bandwidth LORA network connecting the sensor to the cloud. Overall, the paper shows how the PATH2iot system can automatically bring the benefits of edge computing to the increasing set of IoT applications that perform distributed data analytics