On the scalability of LISP and advanced overlaid services

In just four decades the Internet has gone from a lab experiment to a worldwide, business critical infrastructure that caters to the communication needs of almost a half of the Earth's population. With these figures on its side, arguing against the Internet's scalability would seem rather unwise. However, the Internet's organic growth is far from finished and, as billions of new devices are expected to be joined in the not so distant future, scalability, or lack thereof, is commonly believed to be the Internet's biggest problem. While consensus on the exact form of the solution is yet to be found, the need for a semantic decoupling of a node's location and identity, often called a location/identity separation, is generally accepted as a promising way forward. Typically, this requires the introduction of new network elements that provide the binding of the two names-paces and caches that avoid hampering router packet forwarding speeds. But due to this increased complexity the solution's scalability is itself questioned. This dissertation evaluates the suitability of using the Locator/ID Separation Protocol (LISP), one of the most successful proposals to follow the location/identity separation guideline, as a solution to the Internet's scalability problem. However, because the deployment of any new architecture depends not only on solving the incumbent's technical problems but also on the added value that it brings, our approach follows two lines. In the first part of the thesis, we develop the analytical tools to evaluate LISP's control plane scalability while in the second we show that the required control/data plane separation provides important benefits that could drive LISP's adoption. As a first step to evaluating LISP's scalability, we propose a methodology for an analytical analysis of cache performance that relies on the working-set theory to estimate traffic locality of reference. One of our main contribution is that we identify the conditions network traffic must comply with for the theory to be applicable and then use the result to develop a model that predicts average cache miss rates. Furthermore, we study the model's suitability for long term cache provisioning and assess the cache's vulnerability in front of malicious users through an extension that accounts for cache polluting traffic. As a last step, we investigate the main sources of locality and their impact on the asymptotic scalability of the LISP cache. An important finding here is that destination popularity distribution can accurately describe cache performance, independent of the much harder to model short term correlations. Under a small set of assumptions, this result finally enables us to characterize asymptotic scalability with respect to the amount of prefixes (Internet growth) and users (growth of the LISP site). We validate the models and discuss the accuracy of our assumptions using several one-day-long packet traces collected at the egress points of a campus and an academic network. To show the added benefits that could drive LISP's adoption, in the second part of the thesis we investigate the possibilities of performing inter-domain multicast and improving intra-domain routing. Although the idea of using overlaid services to improve underlay performance is not new, this dissertation argues that LISP offers the right tools to reliably and easily implement such services due to its reliance on network instead of application layer support. In particular, we present and extensively evaluate Lcast, a network-layer single-source multicast framework designed to merge the robustness and efficiency of IP multicast with the configurability and low deployment cost of application-layer overlays. Additionally, we describe and evaluate LISP-MPS, an architecture capable of exploiting LISP to minimize intra-domain routing tables and ensure, among other, support for multi protocol switching and virtual networks.En menos de cuatro décadas Internet ha evolucionado desde un experimento de laboratorio hasta una infraestructura de alcance mundial, de importancia crítica para negocios y que atiende a las necesidades de casi un tercio de los habitantes del planeta. Con estos números, es difícil tratar de negar la necesidad de escalabilidad de Internet. Sin embargo, el crecimiento orgánico de Internet está aún lejos de finalizar ya que se espera que mil millones de dispositivos nuevos se conecten en el futuro cercano. Así pues, la falta de escalabilidad es el mayor problema al que se enfrenta Internet hoy en día. Aunque la solución definitiva al problema está aún por definir, la necesidad de desacoplar semánticamente la localización e identidad de un nodo, a menudo llamada locator/identifier separation, es generalmente aceptada como un camino prometedor a seguir. Sin embargo, esto requiere la introducción de nuevos dispositivos en la red que unan los dos espacios de nombres disjuntos resultantes y de cachés que almacenen los enlaces temporales entre ellos con el fin de aumentar la velocidad de transmisión de los enrutadores. A raíz de esta complejidad añadida, la escalabilidad de la solución en si misma es también cuestionada. Este trabajo evalúa la idoneidad de utilizar Locator/ID Separation Protocol (LISP), una de las propuestas más exitosas que siguen la pauta locator/identity separation, como una solución para la escalabilidad de la Internet. Con tal fin, desarrollamos las herramientas analíticas para evaluar la escalabilidad del plano de control de LISP pero también para mostrar que la separación de los planos de control y datos proporciona un importante valor añadido que podría impulsar la adopción de LISP. Como primer paso para evaluar la escalabilidad de LISP, proponemos una metodología para un estudio analítico del rendimiento de la caché que se basa en la teoría del working-set para estimar la localidad de referencias. Identificamos las condiciones que el tráfico de red debe cumplir para que la teoría sea aplicable y luego desarrollamos un modelo que predice las tasas medias de fallos de caché con respecto a parámetros de tráfico fácilmente medibles. Por otra parte, para demostrar su versatilidad y para evaluar la vulnerabilidad de la caché frente a usuarios malintencionados, extendemos el modelo para considerar el rendimiento frente a tráfico generado por usuarios maliciosos. Como último paso, investigamos como usar la popularidad de los destinos para estimar el rendimiento de la caché, independientemente de las correlaciones a corto plazo. Bajo un pequeño conjunto de hipótesis conseguimos caracterizar la escalabilidad con respecto a la cantidad de prefijos (el crecimiento de Internet) y los usuarios (crecimiento del sitio LISP). Validamos los modelos y discutimos la exactitud de nuestras suposiciones utilizando varias trazas de paquetes reales. Para mostrar los beneficios adicionales que podrían impulsar la adopción de LISP, también investigamos las posibilidades de realizar multidifusión inter-dominio y la mejora del enrutamiento dentro del dominio. Aunque la idea de utilizar servicios superpuestos para mejorar el rendimiento de la capa subyacente no es nueva, esta tesis sostiene que LISP ofrece las herramientas adecuadas para poner en práctica de forma fiable y fácilmente este tipo de servicios debido a que LISP actúa en la capa de red y no en la capa de aplicación. En particular, presentamos y evaluamos extensamente Lcast, un marco de multidifusión con una sola fuente diseñado para combinar la robustez y eficiencia de la multidifusión IP con la capacidad de configuración y bajo coste de implementación de una capa superpuesta a nivel de aplicación. Además, describimos y evaluamos LISP-MPS, una arquitectura capaz de explotar LISP para minimizar las tablas de enrutamiento intra-dominio y garantizar, entre otras, soporte para conmutación multi-protocolo y redes virtuales

Path selection and multipath congestion control.

ABSTRACT In this paper we investigate the benefits that accrue from the use of multiple paths by a session coupled with rate control over those paths. In particular, we study data transfers under two classes of multipath control, coordinated control where the rates over the paths are determined as a function of all paths, and uncoordinated control where the rates are determined independently over each path. We show that coordinated control exhibits desirable load balancing properties; for a homogeneous static random paths scenario, we show that the worst-case throughput performance of uncoordinated control behaves as if each user has but a single path (scaling like log(log(N ))/ log(N ) where N is the system size, measured in number of resources). Whereas coordinated control yields a worst-case throughput allocation bounded away from zero. We then allow users to change their set of paths and introduce the notion of a Nash equilibrium. We show that both coordinated and uncoordinated control lead to Nash equilibria corresponding to desirable welfare maximizing states, provided in the latter case, the rate controllers over each path do not exhibit any RTT bias (as in TCP Reno). Finally, we show in the case of coordinated control that more paths are better, leading to greater welfare states and throughput capacity, and that simple path reselection polices that shift to paths with higher net benefit can achieve these states

Hierarchical network topographical routing

Within the last 10 years the content consumption model that underlies many of the assumptions about traffic aggregation within the Internet has changed; the previous short burst transfer followed by longer periods of inactivity that allowed for statistical aggregation of traffic has been increasingly replaced by continuous data transfer models. Approaching this issue from a clean slate perspective; this work looks at the design of a network routing structure and supporting protocols for assisting in the delivery of large scale content services. Rather than approaching a content support model through existing IP models the work takes a fresh look at Internet routing through a hierarchical model in order to highlight the benefits that can be gained with a new structural Internet or through similar modifications to the existing IP model. The work is divided into three major sections: investigating the existing UK based Internet structure as compared to the traditional Autonomous System (AS) Internet structural model; a localised hierarchical network topographical routing model; and intelligent distributed localised service models. The work begins by looking at the United Kingdom (UK) Internet structure as an example of a current generation technical and economic model with shared access to the last mile connectivity and a large scale wholesale network between Internet Service Providers (ISPs) and the end user. This model combined with the Internet Protocol (IP) address allocation and transparency of the wholesale network results in an enforced inefficiency within the overall network restricting the ability of ISPs to collaborate. From this model a core / edge separation hierarchical virtual tree based routing protocol based on the physical network topography (layers 2 and 3) is developed to remove this enforced inefficiency by allowing direct management and control at the lowest levels of the network. This model acts as the base layer for further distributed intelligent services such as management and content delivery to enable both ISPs and third parties to actively collaborate and provide content from the most efficient source