An architecture for dynamic QoS management at Layer 2 for DOCSIS access networks using OpenFlow

Over the last few years, Software-Defined Networking (SDN) has emerged as one of the most disruptive and profitable novelties in networking. SDN was originally conceived to improve performance and reduce costs in Ethernet-based networks and it has been widely adopted in data center and campus networks. Similarly, thanks to the introduction of SDN concepts, access networks will benefit from the higher control, the lower maintenance costs and the better remote access to devices of SDN. However, its application to access networks is not straightforward and imposes great challenges to vendors and network operators, since current SDN technologies are not prepared to handle the provisioning of user equipment, specific port management or QoS requirements of common access networks. Most recent trends dealing with the SDN-ization of access networks advocate for the use of simple devices at the customer premises and the virtualization of the networking functionalities, requiring the provisioning of Layer 2 services in many cases. In such a scenario, this paper presents an architecture that brings SDN to common access networks using legacy equipment. In a nutshell, the architecture is based on the abstraction of the access network as a wide area OpenFlow switch where QoS-enabled pipes are dynamically created leveraging the high granularity of the OpenFlow protocol for packet classification. Furthermore, the OpenFlow protocol itself has been extended in order to support the advanced QoS requirements that are common to most access networks. The architecture has been implemented for DOCSIS access networks and it has been validated and evaluated using a real testbed deployed at our laboratory. The obtained results show that the architecture remains compliant with the ITU-T QoS recommendations and that the cost of introducing the elements required by the architecture in terms of service performance is negligible.European Commission, Seventh Framework Programme, through the ALIEN (317880) project Spanish Ministry of Economy and Competitiveness under the Secure deployment of services over SDN and NFV based networks project S&NSEC TEC2013-47960-C4-3-

Deployment of NFV and SFC scenarios

Aquest ítem conté el treball original, defensat públicament amb data de 24 de febrer de 2017, així com una versió millorada del mateix amb data de 28 de febrer de 2017. Els canvis introduïts a la segona versió són 1) correcció d'errades 2) procediment del darrer annex.Telecommunications services have been traditionally designed linking hardware devices and providing mechanisms so that they can interoperate. Those devices are usually specific to a single service and are based on proprietary technology. On the other hand, the current model works by defining standards and strict protocols to achieve high levels of quality and reliability which have defined the carrier-class provider environment. Provisioning new services represent challenges at different levels because inserting the required devices involve changes in the network topology. This leads to slow deployment times and increased operational costs. To overcome the current burdens network function installation and insertion processes into the current service topology needs to be streamlined to allow greater flexibility. The current service provider model has been disrupted by the over-the-top Internet content providers (Facebook, Netflix, etc.), with short product cycles and fast development pace of new services. The content provider irruption has meant a competition and stress over service providers' infrastructure and has forced telco companies to research new technologies to recover market share with flexible and revenue-generating services. Network Function Virtualization (NFV) and Service Function Chaining (SFC) are some of the initiatives led by the Communication Service Providers to regain the lost leadership. This project focuses on experimenting with some of these already available new technologies, which are expected to be the foundation of the new network paradigms (5G, IOT) and support new value-added services over cost-efficient telecommunication infrastructures. Specifically, SFC scenarios have been deployed with Open Platform for NFV (OPNFV), a Linux Foundation project. Some use cases of the NFV technology are demonstrated applied to teaching laboratories. Although the current implementation does not achieve a production degree of reliability, it provides a suitable environment for the development of new functional improvements and evaluation of the performance of virtualized network infrastructures

Quality of Experience monitoring and management strategies for future smart networks

One of the major driving forces of the service and network's provider market is the user's perceived service quality and expectations, which are referred to as user's Quality of Experience (QoE). It is evident that QoE is particularly critical for network providers, who are challenged with the multimedia engineering problems (e.g. processing, compression) typical of traditional networks. They need to have the right QoE monitoring and management mechanisms to have a significant impact on their budget (e.g. by reducing the users‘ churn). Moreover, due to the rapid growth of mobile networks and multimedia services, it is crucial for Internet Service Providers (ISPs) to accurately monitor and manage the QoE for the delivered services and at the same time keep the computational resources and the power consumption at low levels. The objective of this thesis is to investigate the issue of QoE monitoring and management for future networks. This research, developed during the PhD programme, aims to describe the State-of-the-Art and the concept of Virtual Probes (vProbes). Then, I proposed a QoE monitoring and management solution, two Agent-based solutions for QoE monitoring in LTE-Advanced networks, a QoE monitoring solution for multimedia services in 5G networks and an SDN-based approach for QoE management of multimedia services

Contributions towards softwarization and energy saving in passive optical networks

Ths thesis is a result of contributions to optimize and improve the network management systme and power consumption in Passive Optical Network (PON). Passive Optical Network elements such as Optical Line Terminal (OLT) and Optical Network Units (ONUs) are currently managed by inflexible legacy network management systems. Software-Defined Networking (SDN) is a new networking paradigm that improves the operation and management of networks by decoupling control plane from data plane. Currently, network management in PON networks is not always automated nor normalized. One goal of the researchers in optical networking is to improve the programmability, efficiency, and global optimization of network operations, in order to minimize both Capital Expenditure (CAPEX) and Operational Expenditure (OPEX) by reducing the complexity of devices and its operation. Therefore, it makes sense to use an SDN approach in order to manage the passive optical network functionalities and migrating must of the upper layer functions to the SDN controller. Many approaches have already addressed the topic of applying the SDN architecture in PON networks. However; the focus was usually on facilitating the deployment of SDN-based service and so Service Interoperability remains unexplored in detail. The main challenge toward this goal is how to make compatible the synchronous nature of the EPON media access control protocols with the asynchronous architecture of SDN, and in particular, OpenFlow. In our proposed architecture, the OLT is partially virtualized and some of its functionalities are allocated to the core network management system, while the OLT itself is replaced by an OpenFlow switch. A new MultiPoint MAC Control (MPMC) sublayer extension based on the OpenFlow protocol is presented. The OpenFlow switch is extended with synchronous ports to retain the time-critical nature of the EPON network. Our simulation-based results demonstrate the effectiveness of the new architecture, while retaining a similar (or improved) performance in term of delay and throughput when compared to legacy PONs. Nowadays, many researchers are working simultaneously to develop power saving techniques and improves energy efficiency in the PON network, and since the contribution of access networks to the global energy consumption is large, energy efficiency has become an increasingly important requirement in designing access networks. Therefore, energy-saving approaches are being investigated to provide high performance and consume less energy. Several techniques have been proposed to increase energy efficiency in PON networks. Such techniques are related to the centeralized DBA but the advantage of power saving in a distributed DBA remains untouched. We present a distributed energy-efficient Dynamic Bandwidth Allocation (DBA) algorithm for both the upstream and downstream channels of EPON to improve energy efficiency in EPON networks. The proposed algorithm analyzes the queue status of the ONUs and OLT in order to power-off the transmitter and/or receiver of an ONU whenever there is no upstream or downstream traffic. We have been able to combine the advantage of a distributed DBA such as DDSPON (a smaller packet delay, due to the shorter time needed by DDSPON to allocate the transmission slots) and the energy-saving features (that come at a price of longer packet delays due to the fact that switching off the transmitters make the packet queues grow). Our proposed DBA algorithm minimizes the ONU energy consumption across a wide range of network loads, while maintaining at an acceptable level the penalty introduced in terms of channel utilization and packet delay.Las contribuciones de esta tesis se centran en mejorar el sistema de gestión de red y el consumo de energía en redes de acceso ópticas pasivas (PON). Los elementos de las redes PON, como el terminal de línea óptica (OLT) y las unidades de red ópticas (ONU), se gestionan actualmente mediante sistemas poco flexibles. El nuevo paradigma de redes definidas por software (SDN) mejora la gestión de redes al desacoplar el plano de control del plano de datos. Actualmente, la gestión de redes PON no está automatizada ni normalizada. Uno de los objetivos de los investigadores en redes ópticas es mejorar la programabilidad, la eficiencia y la optimización global de las operaciones de red, con el fin de minimizar tanto el gasto de capital (CAPEX) como el gasto operativo (OPEX) al reducir la complejidad de los dispositivos y su funcionamiento. Por lo tanto, tiene sentido utilizar un enfoque SDN para gestionar las funciones de red óptica pasiva y migrar algunas de las funciones PON de capas superiores al controlador SDN. Otros investigadores han estudiado esta aproximación. sin embargo; el enfoque generalmente estaba en facilitar la implementación del servicio basado en SDN y, por lo tanto, la interoperabilidad de los servicios permanecía sin ser explorado en detalle. El principal desafío hacia este objetivo es cómo compatibilizar la naturaleza síncrona de los protocolos de control de acceso a medios EPON con la arquitectura asíncrona de SDN y, en particular, OpenFlow. En nuestra propuesta de arquitectura, la OLT se virtualiza parcialmente y algunas de sus funcionalidades se asignan al sistema de gestión de red centralizado, mientras que la OLT se reemplaza por un conmutador OpenFlow. Proponemos una nueva extensión de la subcapa de control múltiple de MAC (MPMC) basada en el protocolo OpenFlow. El conmutador OpenFlow se amplía con puertos síncronos para asegurar la naturaleza de tiempo real de la red EPON. Nuestros resultados basados ¿¿en simulaciones demuestran la efectividad de la nueva arquitectura, al tiempo que se mantiene un rendimiento similar (o mejorado) en términos de retardos y rendimiento en comparación con las PON clásicas. Por otro lado, se están desarrollando técnicas de ahorro de energía y mejora de la eficiencia energética en redes PON, y dado que la contribución de las redes de acceso al consumo total de energía es importante, la eficiencia energética se ha convertido en un requisito cada vez más importante. Se han propuesto varias técnicas por parte de otros autores para aumentar la eficiencia energética en las redes PON, relacionadas con algoritmos DBA (Dynamic Bandwidth Allocation) centralizados, pero las ventaja del ahorro de energía en un DBA distribuido no se ha explorado todavía. Por ello nuestra segunda contiribución es un algoritmo distribuido de asignación dinámica de ancho de banda energéticamente eficiente tanto para los canales ascendentes como descendentes de EPON para mejorar la eficiencia energética en las redes EPON. El algoritmo propuesto analiza el estado de cola de las ONU y la OLT para apagar el transmisor y/o el receptor de una ONU cuando no hay tráfico en sentido ascendente o descendente. Hemos podido combinar la ventaja de un DBA distribuido como DDSPON (que asegura retardos más pequeños, debido al menor tiempo que DDSPON necesita para asignar las ranuras de transmisión) y las características de ahorro de energía (al precio de tener retardos de paquete más grandes debido al hecho de que apagar los transmisores hace que las colas de paquetes crezcan). Nuestro algoritmo de DBA propuesto minimiza el consumo de energía de la ONU en una amplia gama de cargas de red, mientras mantiene a un nivel aceptable la penalización introducida en términos de utilización del canal y retardos

Contributions towards softwarization and energy saving in passive optical networks

Ths thesis is a result of contributions to optimize and improve the network management systme and power consumption in Passive Optical Network (PON). Passive Optical Network elements such as Optical Line Terminal (OLT) and Optical Network Units (ONUs) are currently managed by inflexible legacy network management systems. Software-Defined Networking (SDN) is a new networking paradigm that improves the operation and management of networks by decoupling control plane from data plane. Currently, network management in PON networks is not always automated nor normalized. One goal of the researchers in optical networking is to improve the programmability, efficiency, and global optimization of network operations, in order to minimize both Capital Expenditure (CAPEX) and Operational Expenditure (OPEX) by reducing the complexity of devices and its operation. Therefore, it makes sense to use an SDN approach in order to manage the passive optical network functionalities and migrating must of the upper layer functions to the SDN controller. Many approaches have already addressed the topic of applying the SDN architecture in PON networks. However; the focus was usually on facilitating the deployment of SDN-based service and so Service Interoperability remains unexplored in detail. The main challenge toward this goal is how to make compatible the synchronous nature of the EPON media access control protocols with the asynchronous architecture of SDN, and in particular, OpenFlow. In our proposed architecture, the OLT is partially virtualized and some of its functionalities are allocated to the core network management system, while the OLT itself is replaced by an OpenFlow switch. A new MultiPoint MAC Control (MPMC) sublayer extension based on the OpenFlow protocol is presented. The OpenFlow switch is extended with synchronous ports to retain the time-critical nature of the EPON network. Our simulation-based results demonstrate the effectiveness of the new architecture, while retaining a similar (or improved) performance in term of delay and throughput when compared to legacy PONs. Nowadays, many researchers are working simultaneously to develop power saving techniques and improves energy efficiency in the PON network, and since the contribution of access networks to the global energy consumption is large, energy efficiency has become an increasingly important requirement in designing access networks. Therefore, energy-saving approaches are being investigated to provide high performance and consume less energy. Several techniques have been proposed to increase energy efficiency in PON networks. Such techniques are related to the centeralized DBA but the advantage of power saving in a distributed DBA remains untouched. We present a distributed energy-efficient Dynamic Bandwidth Allocation (DBA) algorithm for both the upstream and downstream channels of EPON to improve energy efficiency in EPON networks. The proposed algorithm analyzes the queue status of the ONUs and OLT in order to power-off the transmitter and/or receiver of an ONU whenever there is no upstream or downstream traffic. We have been able to combine the advantage of a distributed DBA such as DDSPON (a smaller packet delay, due to the shorter time needed by DDSPON to allocate the transmission slots) and the energy-saving features (that come at a price of longer packet delays due to the fact that switching off the transmitters make the packet queues grow). Our proposed DBA algorithm minimizes the ONU energy consumption across a wide range of network loads, while maintaining at an acceptable level the penalty introduced in terms of channel utilization and packet delay.Las contribuciones de esta tesis se centran en mejorar el sistema de gestión de red y el consumo de energía en redes de acceso ópticas pasivas (PON). Los elementos de las redes PON, como el terminal de línea óptica (OLT) y las unidades de red ópticas (ONU), se gestionan actualmente mediante sistemas poco flexibles. El nuevo paradigma de redes definidas por software (SDN) mejora la gestión de redes al desacoplar el plano de control del plano de datos. Actualmente, la gestión de redes PON no está automatizada ni normalizada. Uno de los objetivos de los investigadores en redes ópticas es mejorar la programabilidad, la eficiencia y la optimización global de las operaciones de red, con el fin de minimizar tanto el gasto de capital (CAPEX) como el gasto operativo (OPEX) al reducir la complejidad de los dispositivos y su funcionamiento. Por lo tanto, tiene sentido utilizar un enfoque SDN para gestionar las funciones de red óptica pasiva y migrar algunas de las funciones PON de capas superiores al controlador SDN. Otros investigadores han estudiado esta aproximación. sin embargo; el enfoque generalmente estaba en facilitar la implementación del servicio basado en SDN y, por lo tanto, la interoperabilidad de los servicios permanecía sin ser explorado en detalle. El principal desafío hacia este objetivo es cómo compatibilizar la naturaleza síncrona de los protocolos de control de acceso a medios EPON con la arquitectura asíncrona de SDN y, en particular, OpenFlow. En nuestra propuesta de arquitectura, la OLT se virtualiza parcialmente y algunas de sus funcionalidades se asignan al sistema de gestión de red centralizado, mientras que la OLT se reemplaza por un conmutador OpenFlow. Proponemos una nueva extensión de la subcapa de control múltiple de MAC (MPMC) basada en el protocolo OpenFlow. El conmutador OpenFlow se amplía con puertos síncronos para asegurar la naturaleza de tiempo real de la red EPON. Nuestros resultados basados ¿¿en simulaciones demuestran la efectividad de la nueva arquitectura, al tiempo que se mantiene un rendimiento similar (o mejorado) en términos de retardos y rendimiento en comparación con las PON clásicas. Por otro lado, se están desarrollando técnicas de ahorro de energía y mejora de la eficiencia energética en redes PON, y dado que la contribución de las redes de acceso al consumo total de energía es importante, la eficiencia energética se ha convertido en un requisito cada vez más importante. Se han propuesto varias técnicas por parte de otros autores para aumentar la eficiencia energética en las redes PON, relacionadas con algoritmos DBA (Dynamic Bandwidth Allocation) centralizados, pero las ventaja del ahorro de energía en un DBA distribuido no se ha explorado todavía. Por ello nuestra segunda contiribución es un algoritmo distribuido de asignación dinámica de ancho de banda energéticamente eficiente tanto para los canales ascendentes como descendentes de EPON para mejorar la eficiencia energética en las redes EPON. El algoritmo propuesto analiza el estado de cola de las ONU y la OLT para apagar el transmisor y/o el receptor de una ONU cuando no hay tráfico en sentido ascendente o descendente. Hemos podido combinar la ventaja de un DBA distribuido como DDSPON (que asegura retardos más pequeños, debido al menor tiempo que DDSPON necesita para asignar las ranuras de transmisión) y las características de ahorro de energía (al precio de tener retardos de paquete más grandes debido al hecho de que apagar los transmisores hace que las colas de paquetes crezcan). Nuestro algoritmo de DBA propuesto minimiza el consumo de energía de la ONU en una amplia gama de cargas de red, mientras mantiene a un nivel aceptable la penalización introducida en términos de utilización del canal y retardos.Postprint (published version

Contributing to the pathway towards 5G experimentation with an SDN-controlled network box

Καθώς η απαίτηση σε ευρυζωνικές υπηρεσίες κινητών επικοινωνιών αυξάνεται ραγδαία, τα υπάρχοντα δίκτυα κινητών επικοινωνιών πλησιάζουν τα όριά τους κάνοντας επιτακτική την ανάγκη εξέλιξής τους η οποία θα επέλθει με την τεχνολογική άφιξη της επόμενης γενιάς κινητών επικοινωνιών, ευρέως γνωστής ως 5G. Το 5G μεταφέρει όλες εκείνες τις δυνατότητες οι οποίες είναι απαραίτητες για να καλυφθούν οι συνεχώς αυξανόμενες ανάγκες σε ευρυζωνικές υπηρεσίες, να υποστηρίξουν το Internet of Things καθώς και να ενοποιήσουν ετερογενείς υπηρεσίες σε διαφορετικές βιομηχανίες. Η παρούσα διπλωματική εργασία στοχεύει να παρουσιάσει το “Network in a box”, ένα καινοτόμο εργαλείο που αναπτύξαμε στο εργαστήριο, το οποίο βασίζεται επάνω στους θεμέλιους λίθους του 5G, το SDN και το NFV. Με το SDN να είναι η νέα προσέγγιση στα δίκτυα κινητών επικοινωνιών, ο έλεγχος διαχωρίζεται από τα δεδομένα παρέχοντας τη δυνατότητα οποιεσδήποτε αποφάσεις ελέγχου, να λαμβάνονται κεντρικά, μετατρέποντας έτσι τις κλασικές δικτυακές συσκευές σε απλά προωθητικά στοιχεία του δικτύου. Η συγκεκριμένη διάταξη μιμείται ένα πραγματικό δίκτυο, το οποίο διαθέτει δυνατότητες αυτο-οργάνωσης και αυτο-βελτίωσης, προσομοιώνοντας τη λειτουργία του 5G δικτύου. Το συγκεκριμένο εργαλείο είναι επίσης ικανό να παράσχει KPI μετρικές του 5G δικτύου κάτω από πραγματικές συνθήκες ενόσω αληθινές δικτυακές συσκευές είναι συνδεδεμένες σε αυτό. Η δομή της παρούσας διπλωματικής εργασίας αναλύεται σε πέντε κεφάλαια. Το πρώτο κεφάλαιο παρουσιάζει τις προκλήσεις που σύντομα θα κληθούν να αντιμετωπίσουν τα δίκτυα κινητών επικοινωνιών και πώς αυτές μπορούν να καλυφθούν με την τεχνολογία του 5G. Το δεύτερο κεφάλαιο εισάγει την τάση στην αγορά των κινητών επικοινωνιών που διαφένεται πίσω από την επερχόμενη άφιξη του 5G, αποκαλύπτοντας το επιχειρηματικό πλαίσιο για επιχειρήσεις, καταναλωτές και συνεργασίες όπως επίσης και κάποιες περιπτώσεις χρήσης που αντικατοπτρίζουν την διαρκή εξέλιξη στις ευρυζωνικές υπηρεσίες κινητών επικοινωνιών. Το τρίτο κεφάλαιο εμπεριέχει μια μικρή επισκόπηση των τρέχοντων έργων πάνω στο 5G, τα οποία ξεκίνησαν υπό την αιγίδα της Ευρωπαϊκής Επιτροπής με τη συνεργασία προμηθευτών τεχνολογίας επικοινωνιών, παρόχων υπηρεσιών, μικρομεσαίων επιχειρήσεων και πανεπιστημίων. Γίνεται επίσης αναφορά στις βασικές τεχνολογίες του 5G και στις δραστηριότητες προτυποποίησής του. Προχωρώντας στο τέταρτο κεφάλαιο, περιγράφουμε σε βάθος την αρχιτεκτονική του 5G δικτύου, αναλύοντας τα SDN, NFV, MANO και εξετάζουμε πώς αυτά συνεισφέρουν στη βιωσιμότητα του δικτύου. Τέλος, στο πέμπτο κεφάλαιο εισάγουμε μια καινοτόμο ιδέα που αναπτύξαμε στο εργαστήριο δικτύων του πανεπιστημίου μας, ένα πλήρως αυτόνομο δικτυακό εργαλείο, το “Network in a box”. Παρουσιάζουμε σε βάθος πώς αυτός ο server μπορεί να εγκατασταθεί και να λειτουργήσει καθώς και τις δυνατότητές του κάτω από πραγματικές συνθήκες λειτουργίας του δικτύου, ενώ λαμβάνουν χώρα υποβάθμιση ποιότητας ή μη-διαθεσιμότητα στις δικτυακές ζεύξεις, παρέχοντας επίσης μετρικές από τη λειτουργία του δικτύου σε πραγματικό χρόνο.As the demand in mobile broadband is tremendously increased and the heterogeneity of the services to be covered is growing rapidly, current mobile networks are close to their limits imposing the need of an evolution which is going to be introduced by the next generation technology, the ITU IMT-2020, well known as 5G. 5G brings all those capabilities required to cover the increased mobile broadband needs, support the Internet of Things and bind heterogeneous services in different industries. This diploma thesis aims at presenting the “Network in a box”, an innovative tool we developed which is based on the key 5G principles, SDN and NFV. With Software Defined Networking (SDN) being the new approach in mobile networks, control and data plane are decoupled providing the ability to make any control related decisions centrally and transform legacy network devices to simple forwarding elements. This testbed is a portable emulated network device which is self-managed and self-optimised and can be connected between any real network devices, emulating how the 5G network will perform. This plug & play black-box testbed is also capable of providing KPI metrics of the 5G network under real circumstances when real network devices are connected to it. The structure of this diploma thesis is decomposed in five chapters. Chapter 1 presents the challenges mobile networks will shortly face due to the growing heterogeneous demands in communications towards the year 2020 and beyond and how these can be met with the upcoming 5G technology. Chapter 2 introduces the market trend behind the new era of 5G, revealing the business context for enterprises, consumers, verticals and partnerships as well as some use cases which reflect the continuous mobile broadband evolution. Chapter 3 includes a short overview of the ongoing 5G projects, initiated under the umbrella of the European Commission, with the collaboration of communications technology vendors, telecommunications operators, service providers, small and medium-sized enterprises (SMEs) and universities. There is also a reference in 5G key enabling technologies and standardisation activities as we move towards the next generation mobile networks technology. Moving forward, chapter 4 describes in detail the technological components of 5G network architecture such as SDN, NFV, MANO and examines how these 5G key enabling technologies contribute to the overall networks’ sustainability. Finally, in chapter 5 we introduce an innovative idea developed in our university’s communications network research laboratory, an autonomous emulated portable network testbed, the “Network in a box”. We present in-depth how this portable server is deployed, operates and demonstrate the way it can be connected to real network elements emulating a real 5G end-to-end customer network. Moreover, in this last chapter we present “Network in a box” capabilities under real network circumstances when link degradations or failures take place, providing also real-time network metrics

Enabling Edge Computing Using Container Orchestration and Software Defined Networking

With software-defined wide-area networks (SD-WAN) being increasingly adopted, and Kubernetes becoming the de-facto container orchestration tool, the opportunities for deploying edge-computing applications running over a SD-WAN scenario are vast. In this context, a service discovery function will help developing a dynamic infrastructure where clients are able to seek and find particular services. Service discovery also enables a self-healing network capable of detecting the unavailable services. Most of the research in the service discovery field focuses in the discovery of cloud-based services over software-defined networks (SDN). A lack of research in containerized service discovery over SD-WAN is evident. In this thesis, an in-house service discovery solution that works alongside a container orchestrator for allowing an improved traffic handling and better user experience through containerized service discovery and service requests redirection is developed. First, a proof-of-concept SD-WAN topology was implemented alongside a Kubernetes cluster and the in-house service discovery solution. Next, the implementation's performance is tested based on the time required for discovering whether a service has been created, updated or removed. Finally, improvements in node distance computation, local breakout support and the usage of data plane programmability are discussed

Towards lightweight, low-latency network function virtualisation at the network edge

Communication networks are witnessing a dramatic growth in the number of connected mobile devices, sensors and the Internet of Everything (IoE) equipment, which have been estimated to exceed 50 billion by 2020, generating zettabytes of traffic each year. In addition, networks are stressed to serve the increased capabilities of the mobile devices (e.g., HD cameras) and to fulfil the users' desire for always-on, multimedia-oriented, and low-latency connectivity. To cope with these challenges, service providers are exploiting softwarised, cost-effective, and flexible service provisioning, known as Network Function Virtualisation (NFV). At the same time, future networks are aiming to push services to the edge of the network, to close physical proximity from the users, which has the potential to reduce end-to-end latency, while increasing the flexibility and agility of allocating resources. However, the heavy footprint of today's NFV platforms and their lack of dynamic, latency-optimal orchestration prevents them from being used at the edge of the network. In this thesis, the opportunities of bringing NFV to the network edge are identified. As a concrete solution, the thesis presents Glasgow Network Functions (GNF), a container-based NFV framework that allocates and dynamically orchestrates lightweight virtual network functions (vNFs) at the edge of the network, providing low-latency network services (e.g., security functions or content caches) to users. The thesis presents a powerful formalisation for the latency-optimal placement of edge vNFs and provides an exact solution using Integer Linear Programming, along with a placement scheduler that relies on Optimal Stopping Theory to efficiently re-calculate the placement following roaming users and temporal changes in latency characteristics. The results of this work demonstrate that GNF's real-world vNF examples can be created and hosted on a variety of hosting devices, including VMs from public clouds and low-cost edge devices typically found at the customer's premises. The results also show that GNF can carefully manage the placement of vNFs to provide low-latency guarantees, while minimising the number of vNF migrations required by the operators to keep the placement latency-optimal

COMPOSER: A compact open-source service platform

Compute and network virtualization enable to deliver network services with unprecedented agility and flexibility based on (a) the programmatic placement of service functions across the available infrastructure and (b) the real-time setup of the corresponding network paths. This paper presents and validates COMPOSER, a compact, flexible and high-performance service platform for the deployment of network services. COMPOSER supports multiple virtualization engines (e.g., virtual machines, containers, native network functions) and it can use seamlessly the above different execution environments to instantiate network services belonging to different chains, hence facilitating domain-oriented orchestration and enabling the joint optimization of compute and network resources. We demonstrate that COMPOSER can run on resource-constrained hardware, such as residential gateways, as well as on high-performance servers. Finally, COMPOSER integrates optimized data plane components that enable our platform to reach top-class results with respect to data plane performance as well