{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"id":[{"id":"https:\/\/ror.org\/03mb6wj31","id-type":"ROR","asserted-by":"publisher"},{"id":"https:\/\/www.isni.org\/000000041937028X","id-type":"ISNI","asserted-by":"publisher"},{"id":"https:\/\/www.wikidata.org\/entity\/Q1640731","id-type":"wikidata","asserted-by":"publisher"}],"name":"Universitat Polit\u00e8cnica de Catalunya","acronym":["UPC"]}],"indexed":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T22:26:24Z","timestamp":1769034384614,"version":"3.49.0"},"reference-count":0,"publisher":"Universitat Polit\u00e8cnica de Catalunya","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>Nowadays massive amounts of data are being moved over the Internet thanks to data-hungry applications, Big Data, and multimedia content. Combined with a reduction in cost and augmented reliability for high-speed broadband access, the whole Internet infrastructure is facing new challenges especially when information crosses long geographical distances. That is the case for Wide Area Networks (WANs), which are typically traversed in enterprises with multi-site\r\ndeployments. When a connection is established between end-points that are geographically distant with high latency and high bandwidth, data is flowing over a so-called Long Fat Network. Currently, transport protocols in end-points are not able to exploit the resources of such links, notably the most common TCP implementations still stuffer from design flaws that limit their efficiency. More recent developments still suffer from low fairness in resource sharing and lack of\r\nglobal visibility.\r\nWe identify SD-WAN as an SDN use-case that can enable new transport protocols adoption, improving traffic behavior over WANs, without the need to modify the end-points. In this thesis, we explore new approaches to network measurements that will enable both end-points and SD-WAN edge routers, to gain visibility over the end-to-end network status. Such additional visibility promotes the development of smarter control mechanisms for network traffic.\r\nThe preliminary study carried on comprises TCP behavior over WANs and existing methodologies to control its traffic patterns and enforce rate throttling. We also identify a specific use case that poses challenges for WAN scenarios: the Split TCP connections in a Performance Enhancing Proxy (PEP). New control\r\nmechanisms to improve resource utilization and fairness are defined in this project. Specifically, we propose a new approach called Receive Window Modulation (RWM) that allows edge-routers to control the sending rate of a TCP connection by modifying the window advertised by the receiver. We prove that such a controller can improve TCP efficiency and fairness by leveraging local information and additional contextual information obtained from network measurements.\r\nIt also provides a lossless throttling mechanism, allowing for policy enforcement without hindering TCP throughput. We validate RWM in a real experimental scenario, showing improvements of up to 70% in TCP throughput when coupled with loss-based congestion controls. Bufferbloat is also mitigated, reducing the\r\nend-to-end TCP latency measured almost three-fold in some scenarios.\r\nAnother contribution of this project includes a new method to estimate network available bandwidth from TCP passive probings based on the statistical analysis of the Inter-Packet arrival time (SABES). The methodology is based on the packet dispersion model and takes advantage of state-of-the-art machine learning techniques to improve its accuracy, including Deep Neural Networks and Kernel Density Estimation. We validate the model in both simulations and real-world\r\nexperiments, obtaining a median of the mean absolute error distribution of less than 10% of the network capacity.\r\nWe study network capacity estimation and bottleneck detection with an innovative active probing approach called HIRE. We propose a new packet dispersion model that takes into account the packet pairs delay, allowing for precise end-to-end capacity estimation. HIRE also introduces the concept of Hidden packets Red-shift Effect, which consists of injecting TTL expiring packets in between probing pairs at a specific rate. This technique allows locating the narrow link position along the path. We validate the model in simulations obtaining an estimation error of less than 3% in most scenarios. All these contributions constitute the building blocks of a Stateful Edge Router Architecture, SERA. Such architecture is presented in the final part of the dissertation, preparing the ground for future developments.<\/jats:p>\n                <jats:p>Hoy en d\u00eda, Internet mueve cantidades considerables de datos debido a aplicaciones que requieren muchos datos (Big Data). En combinaci\u00f3n con una reducci\u00f3n en los costes y un aumento en la fiabilidad de los enlaces de acceso a banda ancha, la infraestructura de Internet tiene que hacer frente a nuevos retos, especialmente cuando la informaci\u00f3n tiene que atravesar grandes distancias geogr\u00e1ficas. Esto es el caso de las Redes de Area Extendida (WANs), que t\u00edpicamente forman parte de la infraestructura de empresas con distintas sedes y oficinas. Hoy en d\u00eda, los protocoles de transporto en los puntos finales no son capaces de explotar los recursos de las WANs, las mas comunes siendo implementaciones de TCP, las cuales todav\u00eda sufren de fallos en sus dise\u00f1os que limitan la eficiencia. Desarrollos TCP recientes todav\u00eda no garantizan una repartici\u00f3n equitativa de los recursos de red y faltan de visibilidad global. Identificamos SD-WAN como un caso de uso el cual puede facilitar la adopci\u00f3n de nuevos protocoles de transporte, mejorando el comportamiento del trafico de red sobre WANs, sin la necesidad de modificar los puntos finales. En esta tesis exploramos nuevas propuestas en el campo de las medidas de red, las cuales permiten tanto a puntos finales como a router de borde, de ganar visibilidad sobre el estado de la red. Dicha visibilidad a\u00f1adida permite el desarrollo de mecanismos de control del trafico de red mas inteligentes. Identificamos un caso de uso especifico que pone retos en los escenarios WAN: las conexiones Split TCP en el caso de un Performance Enhancing Proxy (PEP). En el proyecto vienen definidos nuevos mecanismos que mejoran la explotaci\u00f3n y repartici\u00f3n de los recursos de red. En concreto, proponemos un nuevo esquema llamado Receive Window Modulation (RWM), que permite a los routers de borde controlar la ratio de env\u00edo de una conexi\u00f3n TCP modificando la ventana de recepci\u00f3n declarada por el recibidor. Probamos que dicho controlador puede mejorar la eficiencia y equidad de TCP, utilizando informaciones locales y de contexto obtenidas por medio de medidas de red. RWM tambi\u00e9n provee un mecanismo de control del trafico privo de perdidas sin da\u00f1ar el rendimiento de TCP. Hemos validado RWM en un entorno experimental real, demostrando mejoras de hasta el 70% en el rendimiento de TCP. El fen\u00f3meno de bufferbloat tambi\u00e9n viene mitigado, reduciendo la latencia medida hasta tres veces en algunos escenarios. Hemos estudiado un m\u00e9todo de estimaci\u00f3n del ancho de banda disponible basado en el an\u00e1lisis estad\u00edstico de muestras de trafico TCP y de su tiempo de llegada entre paquetes, llamado SABES. La metodolog\u00eda se basa en modelo de dispersi\u00f3n de los paquetes y utiliza t\u00e9cnicas de aprendizaje autom\u00e1tico para mejorar su precisi\u00f3n, incluyendo redes neurales profundas (DNN) y estimaci\u00f3n de densidad de kernel (KDE). Hemos validado el modelo tanto en entornos simulados como en experimentos reales, obteniendo una mediana del error medio absoluto menor del 10% de la capacidad de red. Tambi\u00e9n hemos estudiado la estimaci\u00f3n de la capacidad de red y detecci\u00f3n de cuellos de botella con una t\u00e9cnica innovadora que utiliza sondeo activo, que llamamos HIRE. Proponemos un nuevo modelo de dispersi\u00f3n de paquetes el cual tiene en cuenta la latencia de la pareja de paquetes, permitiendo estimar con elevada precisi\u00f3n la capacidad del camino. HIRE tambi\u00e9n introduce el concepto de Efecto de corrimiento al rojo para paquetes escondidos, el cual consiste en inyectar paquetes que caducaran debido a su TTL entre parejas de sondeo activo a una ratio de env\u00edo especifica. Esta t\u00e9cnica permite localizar la posici\u00f3n del enlace a capacidad menor en el camino. Hemos validado el modelo en entornos simulados obteniendo un error de estimaci\u00f3n inferior al 3% en la mayor\u00eda de los escenarios. Una arquitectura que re\u00fane todos los componentes introducidos viene presentada la parte final de la tesis, preparando el terreno para desarrollo de futuros desarrollos<\/jats:p>","DOI":"10.5821\/dissertation-2117-340965","type":"dissertation","created":{"date-parts":[[2023,7,19]],"date-time":"2023-07-19T03:43:33Z","timestamp":1689738213000},"approved":{"date-parts":[[2020,12,4]]},"source":"Crossref","is-referenced-by-count":0,"title":["Definition of new WAN paradigms enabled by smart measurements"],"prefix":"10.5821","author":[{"sequence":"additional","affiliation":[]},{"given":"Francesco","family":"Ciaccia","sequence":"first","affiliation":[]}],"member":"3865","container-title":[],"original-title":[],"deposited":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T06:44:33Z","timestamp":1768977873000},"score":1,"resource":{"primary":{"URL":"https:\/\/hdl.handle.net\/2117\/340965"}},"subtitle":[],"editor":[{"given":"Ren\u00e9","family":"Serral Graci\u00e0","sequence":"first","affiliation":[]},{"given":"Mario","family":"Nemirovsky","sequence":"additional","affiliation":[]}],"short-title":[],"issued":{"date-parts":[[null]]},"references-count":0,"URL":"https:\/\/doi.org\/10.5821\/dissertation-2117-340965","relation":{},"subject":[]}}