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

GAME THEORETIC FLOW AND ROUTING CONTROL FOR COMMUNICATION NETWORKS

As the need to support high speed data exchange in modern communication networks grows rapidly, effective and fair sharing of the network resources becomes very important. Today's communication networks typically involve a large number of users that share the same network resources but may have different, and often competing, objectives. Advanced network protocols that are implemented to optimize the performance of such networks typically assume that the users are passive and are willing to accept compromising their own performance for the sake of optimizing the performance of the overall network. However, considering the trend towards more decentralization in the future, it is natural to assume that the users in a large network may take a more active approach and become more interested in optimizing their own individual performances without giving much consideration to the overall performance of the network. A similar situation occurs when the users are members of teams that are sharing the network resources. A user may find itself cooperating with other members of its team which itself is competing with the other teams in the network. Game theory appears to provide the necessary framework and mathematical tools for formulating and analyzing the strategic interactions among users, or teams of users, of such networks. In this thesis, we investigate networks in which users, or teams of users, either compete or cooperate for the same network resources. We considered two important network topologies and used many examples to illustrate the various solution concepts that we have investigated.. First we consider two-nodeiiiparallel link networks with non-cooperative users trying to optimally distribute their flows among the links. For these networks, we established a condition which guarantees the existence and uniqueness of a Nash equilibrium for the link flows. We derived an analytical expression for the Nash equilibrium and investigated its properties in terms of the network parameters and the users preferences. We showed that in a competitive environment users can achieve larger flow rates by properly emphasizing the corresponding term in their utility functions, but that this can only be done at the expense of an increase in the expected delay. Next, we considered a general network structure with multiple links, multiple nodes, and multiple competing users. We proved the existence of a unique Nash equilibrium. We also investigated many of its intuitive properties. We also extended the model to a network where multiple teams of users compete with each other while cooperating within the teams to optimize a team level performance. For this model, we studied the Noninferior Nash solution and compared its results with the standard Nash equilibrium solution

Energy sustainable paradigms and methods for future mobile networks: A survey

In this survey, we discuss the role of energy in the design of future mobile networks and, in particular, we advocate and elaborate on the use of energy harvesting (EH) hardware as a means to decrease the environmental footprint of 5G technology. To take full advantage of the harvested (renewable) energy, while still meeting the quality of service required by dense 5G deployments, suitable management techniques are here reviewed, highlighting the open issues that are still to be solved to provide eco-friendly and cost-effective mobile architectures. Several solutions have recently been proposed to tackle capacity, coverage and efficiency problems, including: C-RAN, Software Defined Networking (SDN) and fog computing, among others. However, these are not explicitly tailored to increase the energy efficiency of networks featuring renewable energy sources, and have the following limitations: (i) their energy savings are in many cases still insufficient and (ii) they do not consider network elements possessing energy harvesting capabilities. In this paper, we systematically review existing energy sustainable paradigms and methods to address points (i) and (ii), discussing how these can be exploited to obtain highly efficient, energy self-sufficient and high capacity networks. Several open issues have emerged from our review, ranging from the need for accurate energy, transmission and consumption models, to the lack of accurate data traffic profiles, to the use of power transfer, energy cooperation and energy trading techniques. These challenges are here discussed along with some research directions to follow for achieving sustainable 5G systems.Comment: Accepted by Elsevier Computer Communications, 21 pages, 9 figure

Technology Directions for the 21st Century

New technologies will unleash the huge capacity of fiber-optic cable to meet growing demands for bandwidth. Companies will continue to replace private networks with public network bandwidth-on-demand. Although asynchronous transfer mode (ATM) is the transmission technology favored by many, its penetration will be slower than anticipated. Hybrid networks - e.g., a mix of ATM, frame relay, and fast Ethernet - may predominate, both as interim and long-term solutions, based on factors such as availability, interoperability, and cost. Telecommunications equipment and services prices will decrease further due to increased supply and more competition. Explosive Internet growth will continue, requiring additional backbone transmission capacity and enhanced protocols, but it is not clear who will fund the upgrade. Within ten years, space-based constellations of satellites in Low Earth orbit (LEO) will serve mobile users employing small, low-power terminals. 'Little LEO's' will provide packet transmission services and geo-position determination. 'Big LEO's' will function as global cellular telephone networks, with some planning to offer video and interactive multimedia services. Geosynchronous satellites also are proposed for mobile voice grade links and high-bandwidth services. NASA may benefit from resulting cost reductions in components, space hardware, launch services, and telecommunications services

Air Force Institute of Technology Contributions to Air Force Research and Development, Calendar Year 1987

From the introduction:The primary mission of the Air Force Institute of Technology (AFIT) is education, but research and consulting are essential integral elements in the process. This report highlights AFIT\u27s contributions to Air Force research and development activities [in 1987]

Cost-effective Information and Communication Technology (ICT) infrastructure for Tanziania

The research conducted an Information and Communication Technology (ICT) field survey, the results revealed that Tanzania is still lagging behind in the ICT sector due to the lack of an internationally connected terrestrial ICT infrastructure; Internet connectivity to the rest of the world is via expensive satellite links, thus leaving the majority of the population unable to access the Internet services due to its high cost. Therefore, an ICT backbone infrastructure is designed that exploits optical DWDM network technology, which un-locks bandwidth bottlenecks and provides higher capacity which will provide ICT services such as Internet, voice, videos and other multimedia interactions at an affordable cost to the majority of the people who live in the urban and rural areas of Tanzania. The research analyses and compares the performance, and system impairments, in a DWDM system at data transmission rates of 2.5 Gb/s and 10 Gb/s per wavelength channel. The simulation results show that a data transmission rate of 2.5 Gb/s can be successfully transmitted over a greater distance than 10 Gb/s with minimum system impairments. Also operating at the lower data rate delivers a good system performance for the required ICT services. A forty-channel DWDM system will provide a bandwidth of 100 Gb/s. A cost analysis demonstrates the economic worth of incorporating existing optical fibre installations into an optical DWDM network for the creation of an affordable ICT backbone infrastructure; this approach is compared with building a completely new optical fibre DWDM network or a SONET/SDH network. The results show that the ICT backbone infrastructure built with existing SSMF DWDM network technology is a good investment, in terms of profitability, even if the Internet charges are reduced to half current rates. The case for building a completely new optical fibre DWDM network or a SONET/SDH network is difficult to justify using current financial data