Theories and Models for Internet Quality of Service

We survey recent advances in theories and models for Internet Quality of Service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated services, and streaming media playback delays. We also present mechanisms and architecture for scalable support of guaranteed services in the Internet, based on the concept of a stateless core. Methods for scalable control operations are also briefly discussed. We then turn our attention to statistical performance guarantees, and describe several new probabilistic results that can be used for a statistical dimensioning of differentiated services. Lastly, we review recent proposals and results in supporting performance guarantees in a best effort context. These include models for elastic throughput guarantees based on TCP performance modeling, techniques for some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support

Advances in Internet Quality of Service

We describe recent advances in theories and architecture that support performance guarantees needed for quality of service networks. We start with deterministic computations and give applications to integrated services, differentiated services, and playback delays. We review the methods used for obtaining a scalable integrated services support, based on the concept of a stateless core. New probabilistic results that can be used for a statistical dimensioning of differentiated services are explained; some are based on classical queuing theory, while others capitalize on the deterministic results. Then we discuss performance guarantees in a best effort context; we review: methods to provide some quality of service in a pure best effort environment; methods to provide some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support

Strategies for internet route control: past, present and future

Uno de los problemas más complejos en redes de computadores es el de proporcionar garantías de calidad y confiabilidad a las comunicaciones de datos entre entidades que se encuentran en dominios distintos. Esto se debe a un amplio conjunto de razones -- las cuales serán analizadas en detalle en esta tesis -- pero de manera muy breve podemos destacar: i) la limitada flexibilidad que presenta el modelo actual de encaminamiento inter-dominio en materia de ingeniería de tráfico; ii) la naturaleza distribuida y potencialmente antagónica de las políticas de encaminamiento, las cuales son administradas individualmente y sin coordinación por cada dominio en Internet; y iii) las carencias del protocolo de encaminamiento inter-dominio utilizado en Internet, denominado BGP (Border Gateway Protocol).El objetivo de esta tesis, es precisamente el estudio y propuesta de soluciones que permitan mejorar drásticamente la calidad y confiabilidad de las comunicaciones de datos en redes conformadas por múltiples dominios.Una de las principales herramientas para lograr este fin, es tomar el control de las decisiones de encaminamiento y las posibles acciones de ingeniería de tráfico llevadas a cabo en cada dominio. Por este motivo, esta tesis explora distintas estrategias de como controlar en forma precisa y eficiente, tanto el encaminamiento como las decisiones de ingeniería de tráfico en Internet. En la actualidad este control reside principalmente en BGP, el cual como indicamos anteriormente, es uno de los principales responsables de las limitantes existentes. El paso natural sería reemplazar a BGP, pero su despliegue actual y su reconocida operatividad en muchos otros aspectos, resultan claros indicadores de que su sustitución (ó su posible evolución) será probablemente gradual. En este escenario, esta tesis propone analizar y contribuir con nuevas estrategias en materia de control de encaminamiento e ingeniería de tráfico inter-dominio en tres marcos temporales distintos: i) en la actualidad en redes IP; ii) en un futuro cercano en redes IP/MPLS (MultiProtocol Label Switching); y iii) a largo plazo en redes ópticas, modelando así una evolución progresiva y realista, facilitando el reemplazo gradual de BGP.Más concretamente, este trabajo analiza y contribuye mediante: - La propuesta de estrategias incrementales basadas en el Control Inteligente de Rutas (Intelligent Route Control, IRC) para redes IP en la actualidad. Las estrategias propuestas en este caso son de carácter incremental en el sentido de que interaccionan con BGP, solucionando varias de las carencias que éste presenta sin llegar a proponer aún su reemplazo. - La propuesta de estrategias concurrentes basadas en extender el concepto del PCE (Path Computation Element) proveniente del IETF (Internet Engineering Task Force) para redes IP/MPLS en un futuro cercano. Las estrategias propuestas en este caso son de carácter concurrente en el sentido de que no interaccionan con BGP y pueden ser desplegadas en forma paralela. En este caso, BGP continúa controlando el encaminamiento y las acciones de ingeniería de tráfico inter-dominio del tráfico IP, pero el control del tráfico IP/MPLS se efectúa en forma independiente de BGP mediante los PCEs.- La propuesta de estrategias que reemplazan completamente a BGP basadas en la incorporación de un nuevo agente de control, al cual denominamos IDRA (Inter-Domain Routing Agent). Estos agentes proporcionan un plano de control dedicado, físicamente independiente del plano de datos, y con gran capacidad computacional para las futuras redes ópticas multi-dominio.Los resultados expuestos aquí validan la efectividad de las estrategias propuestas, las cuales mejoran significativamente tanto la concepción como la performance de las actuales soluciones en el área de Control Inteligente de Rutas, del esperado PCE en un futuro cercano, y de las propuestas existentes para extender BGP al área de redes ópticas.One of the most complex problems in computer networks is how to provide guaranteed performance and reliability to the communications carried out between nodes located in different domains. This is due to several reasons -- which will be analyzed in detail in this thesis -- but in brief, this is mostly due to: i) the limited capabilities of the current inter-domain routing model in terms of Traffic Engineering (TE); ii) the distributed and potentially conflicting nature of policy-based routing, where routing policies are managed independently and without coordination among domains; and iii) the clear limitations of the inter-domain routing protocol, namely, the Border Gateway Protocol (BGP). The goal of this thesis is precisely to study and propose solutions allowing to drastically improve the performance and reliability of inter-domain communications. One of the most important tools to achieve this goal, is to control the routing and TE decisions performed by routing domains. Therefore, this thesis explores different strategies on how to control such decisions in a highly efficient and accurate way. At present, this control mostly resides in BGP, but as mentioned above, BGP is in fact one of the main causes of the existing limitations. The natural next-step would be to replace BGP, but the large installed base at present together with its recognized effectiveness in other aspects, are clear indicators that its replacement (or its possible evolution) will probably be gradually put into practice.In this framework, this thesis proposes to to study and contribute with novel strategies to control the routing and TE decisions of domains in three different time frames: i) at present in IP multi-domain networks; ii) in the near-future in IP/MPLS (MultiProtocol Label Switching) multi- domain networks; and iii) in the future optical Internet, modeling in this way a realistic and progressive evolution, facilitating the gradual replacement of BGP.More specifically, the contributions in this thesis can be summarized as follows. - We start by proposing incremental strategies based on Intelligent Route Control (IRC) solutions for IP networks. The strategies proposed in this case are incremental in the sense that they interact with BGP, and tackle several of its well-known limitations. - Then, we propose a set of concurrent route control strategies for MPLS networks, based on broadening the concept of the Path Computation Element (PCE) coming from the IETF (Internet Engineering Task Force). Our strategies are concurrent in the sense that they do not interact directly with BGP, and they can be deployed in parallel. In this case, BGP still controlls the routing and TE actions concerning regular IP-based traffic, but not how IP/MPLS paths are routed and controlled. These are handled independently by the PCEs.- We end with the proposal of a set of route control strategies for multi-domain optical networks, where BGP has been completely replaced. These strategies are supported by the introduction of a new route control element, which we named Inter-Domain Routing Agent (IDRA). These IDRAs provide a dedicated control plane, i.e., physically independent from the data plane, and with high computational capacity for future optical networks.The results obtained validate the effectiveness of the strategies proposed here, and confirm that our proposals significantly improve both the conception and performance of the current IRC solutions, the expected PCE in the near-future, as well as the existing proposals about the optical extension of BGP.Postprint (published version

Improving Pan-African research and education networks through traffic engineering: A LISP/SDN approach

The UbuntuNet Alliance, a consortium of National Research and Education Networks (NRENs) runs an exclusive data network for education and research in east and southern Africa. Despite a high degree of route redundancy in the Alliance's topology, a large portion of Internet traffic between the NRENs is circuitously routed through Europe. This thesis proposes a performance-based strategy for dynamic ranking of inter-NREN paths to reduce latencies. The thesis makes two contributions: firstly, mapping Africa's inter-NREN topology and quantifying the extent and impact of circuitous routing; and, secondly, a dynamic traffic engineering scheme based on Software Defined Networking (SDN), Locator/Identifier Separation Protocol (LISP) and Reinforcement Learning. To quantify the extent and impact of circuitous routing among Africa's NRENs, active topology discovery was conducted. Traceroute results showed that up to 75% of traffic from African sources to African NRENs went through inter-continental routes and experienced much higher latencies than that of traffic routed within Africa. An efficient mechanism for topology discovery was implemented by incorporating prior knowledge of overlapping paths to minimize redundancy during measurements. Evaluation of the network probing mechanism showed a 47% reduction in packets required to complete measurements. An interactive geospatial topology visualization tool was designed to evaluate how NREN stakeholders could identify routes between NRENs. Usability evaluation showed that users were able to identify routes with an accuracy level of 68%. NRENs are faced with at least three problems to optimize traffic engineering, namely: how to discover alternate end-to-end paths; how to measure and monitor performance of different paths; and how to reconfigure alternate end-to-end paths. This work designed and evaluated a traffic engineering mechanism for dynamic discovery and configuration of alternate inter-NREN paths using SDN, LISP and Reinforcement Learning. A LISP/SDN based traffic engineering mechanism was designed to enable NRENs to dynamically rank alternate gateways. Emulation-based evaluation of the mechanism showed that dynamic path ranking was able to achieve 20% lower latencies compared to the default static path selection. SDN and Reinforcement Learning were used to enable dynamic packet forwarding in a multipath environment, through hop-by-hop ranking of alternate links based on latency and available bandwidth. The solution achieved minimum latencies with significant increases in aggregate throughput compared to static single path packet forwarding. Overall, this thesis provides evidence that integration of LISP, SDN and Reinforcement Learning, as well as ranking and dynamic configuration of paths could help Africa's NRENs to minimise latencies and to achieve better throughputs

QoS Provisioning in Converged Satellite and Terrestrial Networks: A Survey of the State-of-the-Art

It has been widely acknowledged that future networks will need to provide significantly more capacity than current ones in order to deal with the increasing traffic demands of the users. Particularly in regions where optical fibers are unlikely to be deployed due to economical constraints, this is a major challenge. One option to address this issue is to complement existing narrow-band terrestrial networks with additional satellite connections. Satellites cover huge areas, and recent developments have considerably increased the available capacity while decreasing the cost. However, geostationary satellite links have significantly different link characteristics than most terrestrial links, mainly due to the higher signal propagation time, which often renders them not suitable for delay intolerant traffic. This paper surveys the current state-of-the-art of satellite and terrestrial network convergence. We mainly focus on scenarios in which satellite networks complement existing terrestrial infrastructures, i.e., parallel satellite and terrestrial links exist, in order to provide high bandwidth connections while ideally achieving a similar end user quality-of-experience as in high bandwidth terrestrial networks. Thus, we identify the technical challenges associated with the convergence of satellite and terrestrial networks and analyze the related work. Based on this, we identify four key functional building blocks, which are essential to distribute traffic optimally between the terrestrial and the satellite networks. These are the traffic requirement identification function, the link characteristics identification function, as well as the traffic engineering function and the execution function. Afterwards, we survey current network architectures with respect to these key functional building blocks and perform a gap analysis, which shows that all analyzed network architectures require adaptations to effectively support converged satellite and terrestrial networks. Hence, we conclude by formulating several open research questions with respect to satellite and terrestrial network convergence.This work was supported by the BATS Research Project through the European Union Seventh Framework Programme under Contract 317533

Towards a cloud enabler : from an optical network resource provisioning system to a generalized architecture for dynamic infrastructure services provisioning

This work was developed during a period where most of the optical management and provisioning system where manual and proprietary. This work contributed to the evolution of the state of the art of optical networks with new architectures and advanced virtual infrastructure services. The evolution of optical networks, and internet globally, have been very promising during the last decade. The impact of mobile technology, grid, cloud computing, HDTV, augmented reality and big data, among many others, have driven the evolution of optical networks towards current service technologies, mostly based on SDN (Software Defined Networking) architectures and NFV(Network Functions Virtualisation). Moreover, the convergence of IP/Optical networks and IT services, and the evolution of the internet and optical infrastructures, have generated novel service orchestrators and open source frameworks. In fact, technology has evolved that fast that none could foresee how important Internet is for our current lives. Said in other words, technology was forced to evolve in a way that network architectures became much more transparent, dynamic and flexible to the end users (applications, user interfaces or simple APIs). This Thesis exposes the work done on defining new architectures for Service Oriented Networks and the contribution to the state of the art. The research work is divided into three topics. It describes the evolution from a Network Resource Provisioning System to an advanced Service Plane, and ends with a new architecture that virtualized the optical infrastructure in order to provide coordinated, on-demand and dynamic services between the application and the network infrastructure layer, becoming an enabler for the new generation of cloud network infrastructures. The work done on defining a Network Resource Provisioning System established the first bases for future work on network infrastructure virtualization. The UCLP (User Light Path Provisioning) technology was the first attempt for Customer Empowered Networks and Articulated Private Networks. It empowered the users and brought virtualization and partitioning functionalities into the optical data plane, with new interfaces for dynamic service provisioning. The work done within the development of a new Service Plane allowed the provisioning of on-demand connectivity services from the application, and in a multi-domain and multi-technology scenario based on a virtual network infrastructure composed of resources from different infrastructure providers. This Service Plane facilitated the deployment of applications consuming large amounts of data under deterministic conditions, so allowing the networks behave as a Grid-class resource. It became the first on-demand provisioning system that at lower levels allowed the creation of one virtual domain composed from resources of different providers. The last research topic presents an architecture that consolidated the work done in virtualisation while enhancing the capabilities to upper layers, so fully integrating the optical network infrastructure into the cloud environment, and so providing an architecture that enabled cloud services by integrating the request of optical network and IT infrastructure services together at the same level. It set up a new trend into the research community and evolved towards the technology we use today based on SDN and NFV. Summing up, the work presented is focused on the provisioning of virtual infrastructures from the architectural point of view of optical networks and IT infrastructures, together with the design and definition of novel service layers. It means, architectures that enabled the creation of virtual infrastructures composed of optical networks and IT resources, isolated and provisioned on-demand and in advance with infrastructure re-planning functionalities, and a new set of interfaces to open up those services to applications or third parties.Aquesta tesi es va desenvolupar durant un període on la majoria de sistemes de gestió de xarxa òptica eren manuals i basats en sistemes propietaris. En aquest sentit, la feina presentada va contribuir a l'evolució de l'estat de l'art de les xarxes òptiques tant a nivell d’arquitectures com de provisió d’infraestructures virtuals. L'evolució de les xarxes òptiques, i d'Internet a nivell mundial, han estat molt prometedores durant l'última dècada. L'impacte de la tecnologia mòbil, la computació al núvol, la televisió d'alta definició, la realitat augmentada i el big data, entre molts altres, han impulsat l'evolució cap a xarxes d’altes prestacions amb nous serveis basats en SDN (Software Defined Networking) i NFV (Funcions de xarxa La virtualització). D'altra banda, la convergència de xarxes òptiques i els serveis IT, junt amb l'evolució d'Internet i de les infraestructures òptiques, han generat nous orquestradors de serveis i frameworks basats en codi obert. La tecnologia ha evolucionat a una velocitat on ningú podria haver predit la importància que Internet està tenint en el nostre dia a dia. Dit en altres paraules, la tecnologia es va veure obligada a evolucionar d'una manera on les arquitectures de xarxa es fessin més transparent, dinàmiques i flexibles vers als usuaris finals (aplicacions, interfícies d'usuari o APIs simples). Aquesta Tesi presenta noves arquitectures de xarxa òptica orientades a serveis. El treball de recerca es divideix en tres temes. Es presenta un sistema de virtualització i aprovisionament de recursos de xarxa i la seva evolució a un pla de servei avançat, per acabar presentant el disseny d’una nova arquitectura capaç de virtualitzar la infraestructura òptica i IT i proporcionar serveis de forma coordinada, i sota demanda, entre l'aplicació i la capa d'infraestructura de xarxa òptica. Tot esdevenint un facilitador per a la nova generació d'infraestructures de xarxa en el núvol. El treball realitzat en la definició del sistema de virtualització de recursos va establir les primeres bases sobre la virtualització de la infraestructura de xarxa òptica en el marc de les “Customer Empowered Networks” i “Articulated Private Networks”. Amb l’objectiu de virtualitzar el pla de dades òptic, i oferir noves interfícies per a la provisió de serveis dinàmics de xarxa. En quant al pla de serveis presentat, aquest va facilitat la provisió de serveis de connectivitat sota demanda per part de l'aplicació, tant en entorns multi-domini, com en entorns amb múltiples tecnologies. Aquest pla de servei, anomenat Harmony, va facilitar el desplegament de noves aplicacions que consumien grans quantitats de dades en condicions deterministes. En aquest sentit, va permetre que les xarxes es comportessin com un recurs Grid, i per tant, va esdevenir el primer sistema d'aprovisionament sota demanda que permetia la creació de dominis virtuals de xarxa composts a partir de recursos de diferents proveïdors. Finalment, es presenta l’evolució d’un pla de servei cap una arquitectura global que consolida el treball realitzat a nivell de convergència d’infraestructures (òptica + IT) i millora les capacitats de les capes superiors. Aquesta arquitectura va facilitar la plena integració de la infraestructura de xarxa òptica a l'entorn del núvol. En aquest sentit, aquest resultats van evolucionar cap a les tendències actuals de SDN i NFV. En resum, el treball presentat es centra en la provisió d'infraestructures virtuals des del punt de vista d’arquitectures de xarxa òptiques i les infraestructures IT, juntament amb el disseny i definició de nous serveis de xarxa avançats, tal i com ho va ser el servei de re-planificació dinàmicaPostprint (published version

Quality Of Service Enhancement In Ip Based Networks Using Diffserv

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2003Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2003Bu çalışmada, Diffserv mimarisi ile internet üzerinde servis kalitesi sağlama tartışılmıştır. Son on yılda IP tabanlı internette servis kalitesi sağlanamıyordu. İnternette bugün sağlanabilen tek servis ‘Best Effort (BE)’ adı verilen servistir. Yani, ağ, herhangi bir paketi hedefine ulaştırırken mümkün olan en verimli yolu kullanır ancak herhangi bir garanti ya da kaynak ayırımı yapmaz. Başka bir deyişle, trafik mümkün olduğu kadar hızlı ve herhangi bir zaman sınırı ya da miktar açısından garanti verilmeden işlenir. İnternetin ticari bir yapıya bürünmesiyle ‘Servis Kalitesi’ sağlanma ihtiyacı daha da artmıştır. Bu ihtiyaç farklı mimarilerin doğmasına yol açmıştır: IntServ ve DiffServ olmak üzere.Tez çalışmasında DiffServ mimarisi problem ve avantajlarıyla ele alınmıştır. Son bölümde ise NS2 ağ simulasyon yazılımı kullanılarak DiffServ implementasyonları yapılmış sonuçları karşılaştırmalı olarak verilmiştir.In this study improving Quality of Service (QoS) on the Internet with DiffServ architecture is discussed. Within the past decade, it is certainly not support for Quality of Service (QoS) over the IP-based ubiquitous Internet. The Internet as it stands today only support one service class called -Best-Effort (BE) Service. The network would make an earnest attempt to deliver packets to their destinations but with no guarantees and/or special resources allocated for any of the packets. With another words, traffic is processed as quickly as possible but there is no guarantee as to timeliness or actual delivery or even how much can be delivered (i.e. throughput). With the rapid transformation of the Internet into a commercial infrastructure, demands for Quality of Service (QoS) have rapidly developed. This need was resulted to different architectures: IntServ and DiffServ. In the study some DiffServ implementations are discussed with their problems and gains. At the last section with using NS2 simulation programming language some DiffServ implementations are given with the compared results.Yüksek LisansM.Sc

Traffic Re-engineering: Extending Resource Pooling Through the Application of Re-feedback

Parallelism pervades the Internet, yet efficiently pooling this increasing path diversity has remained elusive. With no holistic solution for resource pooling, each layer of the Internet architecture attempts to balance traffic according to its own needs, potentially at the expense of others. From the edges, traffic is implicitly pooled over multiple paths by retrieving content from different sources. Within the network, traffic is explicitly balanced across multiple links through the use of traffic engineering. This work explores how the current architecture can be realigned to facilitate resource pooling at both network and transport layers, where tension between stakeholders is strongest. The central theme of this thesis is that traffic engineering can be performed more efficiently, flexibly and robustly through the use of re-feedback. A cross-layer architecture is proposed for sharing the responsibility for resource pooling across both hosts and network. Building on this framework, two novel forms of traffic management are evaluated. Efficient pooling of traffic across paths is achieved through the development of an in-network congestion balancer, which can function in the absence of multipath transport. Network and transport mechanisms are then designed and implemented to facilitate path fail-over, greatly improving resilience without requiring receiver side cooperation. These contributions are framed by a longitudinal measurement study which provides evidence for many of the design choices taken. A methodology for scalably recovering flow metrics from passive traces is developed which in turn is systematically applied to over five years of interdomain traffic data. The resulting findings challenge traditional assumptions on the preponderance of congestion control on resource sharing, with over half of all traffic being constrained by limits other than network capacity. All of the above represent concerted attempts to rethink and reassert traffic engineering in an Internet where competing solutions for resource pooling proliferate. By delegating responsibilities currently overloading the routing architecture towards hosts and re-engineering traffic management around the core strengths of the network, the proposed architectural changes allow the tussle surrounding resource pooling to be drawn out without compromising the scalability and evolvability of the Internet

Minimal deployable endpoint-driven network forwarding: principle, designs and applications

Networked systems now have significant impact on human lives: the Internet, connecting the world globally, is the foundation of our information age, the data centers, running hundreds of thousands of servers, drive the era of cloud computing, and even the Tor project, a networked system providing online anonymity, now serves millions of daily users. Guided by the end-to-end principle, many computer networks have been designed with a simple and flexible core offering general data transfer service, whereas the bulk of the application-level functionalities have been implemented on endpoints that are attached to the edge of the network. Although the end-to-end design principle gives these networked systems tremendous success, a number of new requirements have emerged for computer networks and their running applications, including untrustworthy of endpoints, privacy requirement of endpoints, more demanding applications, the rise of third-party Intermediaries and the asymmetric capability of endpoints and so on. These emerging requirements have created various challenges in different networked systems. To address these challenges, there are no obvious solutions without adding in-network functions to the network core. However, no design principle has ever been proposed for guiding the implementation of in-network functions. In this thesis, We propose the first such principle and apply this principle to propose four designs in three different networked systems to address four separate challenges. We demonstrate through detailed implementation and extensive evaluations that the proposed principle can live in harmony with the end-to-end principle, and a combination of the two principle offers more complete, effective and accurate guides for innovating the modern computer networks and their applications.Ope