A framework for Traffic Engineering in software-defined networks with advance reservation capabilities

298 p.En esta tesis doctoral se presenta una arquitectura software para facilitar la introducción de técnicas de ingeniería de tráfico en redes definidas por software. La arquitectura ha sido diseñada de forma modular, de manera que soporte múltiples casos de uso, incluyendo su aplicación en redes académicas. Cabe destacar que las redes académicas se caracterizan por proporcionar servicios de alta disponibilidad, por lo que la utilización de técnicas de ingeniería de tráfico es de vital importancia a fin de garantizar la prestación del servicio en los términos acordados. Uno de los servicios típicamente prestados por las redes académicas es el establecimiento de circuitos extremo a extremo con una duración determinada en la que una serie de recursos de red estén garantizados, conocido como ancho de banda bajo demanda, el cual constituye uno de los casos de uso en ingeniería de tráfico más desafiantes. Como consecuencia, y dado que esta tesis doctoral ha sido co-financiada por la red académica GÉANT, la arquitectura incluye soporte para servicios de reserva avanzada. La solución consiste en una gestión de los recursos de red en función del tiempo, la cual mediante el empleo de estructuras de datos y algoritmos específicamente diseñados persigue la mejora de la utilización de los recursos de red a la hora de prestar este tipo de servicios. La solución ha sido validada teniendo en cuenta los requisitos funcionales y de rendimiento planteados por la red GÉANT. Así mismo, cabe destacar que la solución será utilizada en el despliegue piloto del nuevo servicio de ancho de banda bajo demanda de la red GÉANT a finales del 2017

Enhancing performance of conventional computer networks employing selected SDN principles

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThis research is related to computer networks. In this thesis, three main issues are addressed which affect the performance of any computer network: congestion, efficient resources utilization and link failure. Those issues are related to each other in many situations. Many approaches have been suggested to deal with those issues as well as many solutions were applied. Despite all the improvements of the technology and the proposed solutions, those issues continue to be a burden on the system’s performance. This effect is related to the increase of the Quality of Service (QoS) requirements in modern networks. The basic idea of this research is evolving the intelligence of a conventional computer network when dealing with those issues by adding some features of the Software Defined Networking (SDN). This adoption upgrades the conventional computer network system to be more dynamic and higher self-organizing when dealing with those issues. This idea is applied on a system represented by a computer network that uses the Open Shortest Path First (OSPF) routing protocol. The first improvement deals with the distribution of Internet Protocol (IP) routed flows. The second improvement deals with tunnel establishment that serves Multi-Protocol Label Switching (MPLS) routed flows and the third improvement deals with bandwidth reservation when applying network restoration represented by Fast Re-route (FRR) mechanism to sooth the effect of link failure in OSPF/MPLS routed network. This idea is also applied on another system that uses the Enhanced Interior Gateway Routing Protocol (EIGRP) to improve the performance of its routing algorithm. Adopting the SDN notion is achieved by adding an intelligent controller to the system and creating a dialog of messages between the controller and the conventional routers. This requires upgrading the routers to respond to the new modified system.Our proposed approaches are presented with simulations of different configurations which produce fine results

A framework for Traffic Engineering in software-defined networks with advance reservation capabilities

298 p.En esta tesis doctoral se presenta una arquitectura software para facilitar la introducción de técnicas de ingeniería de tráfico en redes definidas por software. La arquitectura ha sido diseñada de forma modular, de manera que soporte múltiples casos de uso, incluyendo su aplicación en redes académicas. Cabe destacar que las redes académicas se caracterizan por proporcionar servicios de alta disponibilidad, por lo que la utilización de técnicas de ingeniería de tráfico es de vital importancia a fin de garantizar la prestación del servicio en los términos acordados. Uno de los servicios típicamente prestados por las redes académicas es el establecimiento de circuitos extremo a extremo con una duración determinada en la que una serie de recursos de red estén garantizados, conocido como ancho de banda bajo demanda, el cual constituye uno de los casos de uso en ingeniería de tráfico más desafiantes. Como consecuencia, y dado que esta tesis doctoral ha sido co-financiada por la red académica GÉANT, la arquitectura incluye soporte para servicios de reserva avanzada. La solución consiste en una gestión de los recursos de red en función del tiempo, la cual mediante el empleo de estructuras de datos y algoritmos específicamente diseñados persigue la mejora de la utilización de los recursos de red a la hora de prestar este tipo de servicios. La solución ha sido validada teniendo en cuenta los requisitos funcionales y de rendimiento planteados por la red GÉANT. Así mismo, cabe destacar que la solución será utilizada en el despliegue piloto del nuevo servicio de ancho de banda bajo demanda de la red GÉANT a finales del 2017

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

Traffic Control in Packet Switched Networks

This thesis examines traffic control options available in two existing routing solutions in packet-switched networks. The first solution is the shortest path hop-by-hop routing deployed with the OSPF or IS-IS routing protocol and the IP forwarding protocol. This is the initially deployed and still the most popular routing solution in the Internet. The second solution is explicit routing implemented with the RSVP-TE or CR-LDP signalling protocol and the MPLS forwarding protocol. This is the latest solution to have become widely deployed in the Internet. The thesis analyses the limitations of the two routing solutions as tools for traffic control and yields new insights that can guide the analysis and design of protocols involved in the process. A set of recommendations for modifications of the existing protocols is provided which would allow for a range of new traffic control approaches to be deployed in packet-switched networks. For future routing solutions which comply with the proposed recommendations two new algorithms are presented in the thesis. They are called the Link Mask Topology (LMT) algorithm, and the Link Cost Topology (LCT) algorithm. The two algorithms define a set of routing topologies and assign network traffic to routes available in these topologies aiming to simultaneously achieve high network throughput and fair resource allocation. While there are similarities in the operation of the two algorithms, their applicability is different as they allocate resources to multiple paths between two network nodes which are available in the defined routing topologies according to a different rule set. The LMT algorithm directs traffic sent between any pair of network nodes to a single route. The LCT algorithm directs traffic sent between a pair of network nodes to a number of routes. The performance of the two proposed algorithms is evaluated in the thesis with calculations comparing them to the shortest path routing algorithm in a number of test cases. The test results demonstrate the potentials of the two proposed algorithms in improving the performance of networks which employ shortest path routing

Scalability and Resilience Analysis of Software-Defined Networking

Software-defined Networking (SDN) ist eine moderne Architektur für Kommunikationsnetze, welche entwickelt wurde, um die Einführung von neuen Diensten und Funktionen in Netzwerke zu erleichtern. Durch eine Trennung der Weiterleitungs- und Kontrollfunktionen sind nur wenige Kontrollelemente mit Software-Updates zu versehen, um Veränderungen am Netz vornehmen zu können. Allerdings wirft die Netzstrukturierung von SDN neue Fragen bezüglich Skalierbarkeit und Ausfallsicherheit auf, welche in dezentralen Netzstrukturen nicht auftreten. In dieser Arbeit befassen wir uns mit Fragestellungen zu Skalierbarkeit und Ausfallsicherheit in Bezug auf Unicast- und Multicast-Verkehr in SDN-basierten Netzen. Wir führen eine Komprimierungstechnik für Routingtabellen ein, welche die Skalierungsproblematik aktueller SDN Weiterleitungsgeräte verbessern soll und ermitteln ihre Effizienz in einer Leistungsbewertung. Außerdem diskutieren wir unterschiedliche Methoden, um die Ausfallsicherheit in SDN zu verbessern. Wir analysieren sie auf öffentlich zugänglichen Netzwerken und benennen Vor- und Nachteile der Ansätze. Abschließend schlagen wir eine skalierbare und ausfallsichere Architektur für Multicast-basiertes SDN vor. Wir untersuchen ihre Effizienz in einer Leistungsbewertung und zeigen ihre Umsetzbarkeit mithilfe eines Prototypen.Software-Defined Networking (SDN) is a novel architecture for communication networks that has been developed to ease the introduction of new network services and functions. It leverages the separation of the data plane and the control plane to allow network services to be deployed solely in software. Although SDN provides great flexibility, the applicability of SDN in communication networks raises several questions with regard to scalability and resilience against network failures. These concerns are not prevalent in current decentralized network architectures. In this thesis, we address scalability and resilience issues with regard to unicast and multicast traffic for SDN-based networks. We propose a new compression method for inter-domain routing tables to address hardware limitations of current SDN switches and analyze its effectiveness. We propose various resilience methods for SDN and identify their key performance indicators in the context of carrier-grade and datacenter networks. We discuss the advantages and disadvantages of these proposals and their appropriate use cases. Finally, we propose a scalable and resilient software-defined multicast architecture. We study the effectiveness of our approach and show its feasibility using a prototype implementation

Overlay auxiliary routing: achieving near minimum delay routing solutions for overlay networks.

Zhang Li.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.Includes bibliographical references (leaves 71-74).Abstracts in English and Chinese.Abstract --- p.ii摘要 --- p.ivAcknowledgments --- p.vContents --- p.viChapter Chapter 1 --- Introduction --- p.1Chapter Chapter 2 --- Internet Routing and Performance Studies --- p.5Chapter 2.1 --- Border Gateway Protocol Version 4 (BGP4) --- p.5Chapter 2.2 --- Internet Performance Studies --- p.6Chapter 2.3 --- Improve Routing Performance --- p.8Chapter 2.3.1 --- Traffic Engineering --- p.8Chapter 2.3.2 --- Network-layer Techniques --- p.9Chapter 2.3.3 --- Minimum Delay Routing --- p.11Chapter Chapter 3 --- Overlay-based Techniques --- p.15Chapter 3.1 --- Content Distribution Network --- p.16Chapter 3.2 --- Relative Overlay Techniques --- p.16Chapter Chapter 4 --- Overlay Minimum Delay Routing --- p.19Chapter 4.1 --- Minimum Delay Routing in Overlay Network --- p.21Chapter 4.1.1 --- Problem Formulation --- p.21Chapter 4.1.2 --- Necessary and Sufficient Conditions for Distributed Computing --- p.25Chapter 4.1.3 --- Optimal Overlay Auxiliary Routing (00AR) Algorithm --- p.29Chapter 4.2 --- Performance Comparing with Optimal IP routing --- p.31Chapter Chapter 5 --- Sub-Optimal Overlay Auxiliary Routing Algorithm --- p.39Chapter 5.1 --- Approximation Conditions to Optimal Overlay Routing --- p.40Chapter 5.2 --- SOAR algorithm Overview --- p.44Chapter 5.3 --- Distributing Traffic over Multiple Paths --- p.49Chapter 5.3.1 --- Adaptive load Adjustment --- p.50Chapter 5.3.2 --- Per-flow Routing Control --- p.53Chapter 5.4 --- Discussion on Marginal Delay of an OAR Link --- p.55Chapter Chapter 6 --- Performance Evaluation of Sub-Optimal Overlay Auxiliary Routing --- p.57Chapter 6.1 --- Experiment Method Description --- p.57Chapter 6.2 --- Comparison of overall delay --- p.61Chapter 6.3 --- Effect of the Routing update interval parameters xx and yy --- p.64Chapter 6.4 --- Comparison of packet loss rate --- p.66Chapter 6.5 --- Comparison of potential maximum data transmission rate --- p.68Chapter 6.6 --- Stability of the OAR load-balancing heuristics algorithm --- p.69References --- p.71Appendix --- p.7

Exploitation of wireless control link in the software-defined LEO satellite network

software-defined satellite network, control link, cross layer optimization, power-efficient control link algorithmThe low earth orbit (LEO) satellite network can benefit from software-defined networking (SDN) by lightening forwarding devices and improving service diversity. In order to apply SDN into the network, however, reliable SDN control links should be associated from satellite gateways to satellites, with the wireless and mobile properties of the network taken into account. Since these characteristics affect both control link association and gateway power allocation, we define this new cross layer problem as an SDN control link problem. The problem is discussed from the viewpoint of multilayers such as automatic repeat request (ARQ) and gateway power allocation at the Link layer, and split transmit control protocol (TCP) and link scheduling at the Transport layer. A centralized SDN control framework constrained by maximum total power is introduced to enhance gateway power efficiency for control link setup. Based on the power control analysis of the problem, a power-efficient control link algorithm is developed, which establishes low latency control links with reduced power consumption. Along with the sensitivity analysis of the proposed control link algorithm, numerical results demonstrate low latency and high reliability of control links established by the algorithm, ultimately suggesting the feasibility, both technical and economical, of the software-defined LEO satellite network.open1. INTRODUCTION 1 1.1 Software-Defined Satellite Network 1 1.2 Wireless SDN Control Link Problem Statement 4 1.3 Contributions and Overview of Theses 5 1.4 Related Works 6 2. MODELING AND FORMULATION 8 2.1 Control Link Association 8 2.1.1 Graph Model 8 2.1.2 ARQ and Split TCP 9 2.1.3 Link Association Variable 10 2.2 Control Link Reliability and Expected Latency Formulation 12 2.2.1 Control Link Reliability and Gateway Power 12 2.2.2 Expected Latency Formulation 13 2.3 SDN Control Link Problem 16 2.3.1 Expected Latency Minimization Problem 16 2.3.2 Power-Efficient SDN Control Link Problem 17 3. SDN CONTROL LINK ALGORITHM 22 4. NUMERICAL RESULTS AND ANALYSIS 25 4.1 Latency Analysis and Feasibility of the Software-Defined Satellite Network 27 4.2 Sensitivity Analysis and Selection of the Maximum Total Power 33 5. CONCLUSION 37 APPENDIX 38 REFERENCES 40저궤도(LEO) 위성 네트워크는 데이터 전달 장치를 간소화하고 서비스 다양성을 향상시키는 등, 소프트웨어 정의 네트워킹(SDN)로부터 다양한 이점을 얻을 수 있다. 그러나 SDN을 위성 네트워크에 적용하기 위해서는, 신뢰성 있는 SDN 제어 링크가 위성 게이트웨이로부터 위성까지 연결되어야 하며, 위성 네트워크의 무선 특성과 이동성이 동시에 고려되어야 한다. 이러한 특성들은 제어 링크 연결과 게이트웨이 전력 할당 모두에 영향을 미치기 때문에, 우리는 이러한 교차 계층 문제를 SDN 제어 링크 문제로 새롭게 정의한다. 이 문제는 전송 계층의 자동 재전송 요구(ARQ) 및 전송 제어 프로토콜(TCP), 네트워크 계층의 라우팅, 물리 계층의 전력 할당과 같은 다중 계층의 관점에서 논의된다. 본 논문에서는 제어 링크 설정에 필요한 게이트웨이 전력 효율을 높이기 위해 최대 총 전력을 제한하는 중앙집권화 SDN 제어 프레임워크를 도입한다. 제안된 문제에 대한 전력 할당 분석을 기반으로, 전력 소비가 적으면서도 지연이 적은 제어 링크를 연결하는 전력 효율적인 제어 링크 알고리즘이 제안된다. 제안된 제어 링크 알고리즘의 민감도 분석과 함께, 시뮬레이션 결과는 알고리즘에 의해 설정되는 제어 링크의 낮은 지연과 높은 신뢰성을 보여주며, 궁극적으로 소프트웨어 정의 LEO 위성 네트워크의 기술적 및 경제적 타당성을 제시한다.MasterdCollectio

Resource Allocation, and Survivability in Network Virtualization Environments

Network virtualization can offer more flexibility and better manageability for the future Internet by allowing multiple heterogeneous virtual networks (VN) to coexist on a shared infrastructure provider (InP) network. A major challenge in this respect is the VN embedding problem that deals with the efficient mapping of virtual resources on InP network resources. Previous research focused on heuristic algorithms for the VN embedding problem assuming that the InP network remains operational at all times. In this thesis, we remove that assumption by formulating the survivable virtual network embedding (SVNE) problem and developing baseline policy heuristics and an efficient hybrid policy heuristic to solve it. The hybrid policy is based on a fast re-routing strategy and utilizes a pre-reserved quota for backup on each physical link. Our evaluation results show that our proposed heuristic for SVNE outperforms baseline heuristics in terms of long term business profit for the InP, acceptance ratio, bandwidth efficiency, and response time