Carmen Guerrero

University Carlos III de Madrid | UC3M · Department of Telematic Engineering

IT systems monitoring is a crucial process for managing and orchestrating network resources, allowing network providers to rapidly detect and react to most impediment causing network degradation. However, the high growth in size and complexity of current operational networks (2022) demands new solutions to process huge amounts of data (including al...

A recently proposed direction that is pursued by standardization organizations for 5G Network Function Virtualization (NFV) technologies at the core of next-generation works (5G and beyond) is the adoption of “Cloud-native” design principles. These principles are catalyzed by Platform as a Service (PaaS) solutions that allow re-usability of common...

This Editorial summarizes the Special Issue entitled Challenges and Solutions for hybrid SDN (Chal. & sol. HSDN) published in Elsevier’s Computer Networks during 2021. We first provide the motivation and context for such a Special Issue, followed by a short explanation and classification of the articles accepted for publication, and concluded with...

In the context of the emergent Software-Defined Networking (SDN) paradigm, the attention is mostly directed to the evolution of control protocols and networking functionalities. However, network professionals also need the right tools to reach the same level—and beyond—of monitoring and control they have in traditional networks. Current SDN tools a...

The Software-Defined Networking (SDN) paradigm allows networking hardware to be made “malleable” and remotely manageable by the so-called SDN controllers. However, the current SDN landscape is extremely fragmented. Different open and closed source controller frameworks such as OpenDaylight, Ryu, Floodlight, etc. exist. Porting SDN applications from...

The networking research community has started looking into key questions on energy efficiency of communication networks. The European Commission activated under the FP7 the TREND Network of Excellence with the goal of establishing the integration of the EU research community in green networking with a long perspective to consolidate the European le...

Twitter is one of the most popular applications in the current Internet with more than 500 M registered users across the world. In this paper, we conduct a comprehensive analysis to understand the geographical characteristics of Twitter using cross-community mining techniques. Specifically, we study the locality level shown by the three main elemen...

We study the problem of reducing power consumption in an Internet Service Provider (ISP) network by designing the content distribution infrastructure managed by the operator. We propose an algorithm to optimally decide where to cache the content inside the ISP network. We evaluate our solution over two case studies driven by operators feedback. Res...

BitTorrent is the most popular peer-to-peer (P2P) content delivery application where individual users share various types of content with tens of thousands of other users. The growing popularity of BitTorrent is primarily due to the availability of valuable content without any cost for the consumers. However, apart from the required resources, publ...

Aimed at answering important questions about the energy demand of current telecom infrastructure and the design of sustainable and energy-efficient future networks, the research of a number of European partners is brought together in the TREND project. In this paper we present the achievements of the Work Package coordinating the experimental activ...

BitTorrent is one of the most important applications in the current Internet. Despite of its interest, we still have little knowledge regarding the connectivity properties of real BitTorrent swarms. In this paper we leverage a dataset including the connectivity information of 250 real torrents and more than 150k peers to carefully study the connect...

Routing in vehicular network is a challenging task due to network partitioning, high vehicular speed, and city environment characteristics. These characteristics results in degraded performance in traditional routing protocols. Traditional routing protocols, addressing the issues of mobile ad hoc network, are applicable for MANET applications. Posi...

This paper briefly describes the objectives of the TREND (Toward Real Energy-efficient Network Design) Network of Excellence of the European Commission 7th Framework Programme, and outlines some of the main results obtained so far within the project, looking at wireless access networks, core networks, and content distribution issues.

This paper reports the results of experiments from an implementation of H-P2PSIP, a hierarchical overlay architecture based on the ongoing work in the IETF P2PSIP Working Group. This architecture allows the exchange of information among different independent overlay networks through the use of a two-layer architecture based on super-peers and hiera...

The current Online Social Networks' infrastructure is com-posed by thousands of servers distributed across data-centers spread over several geographical locations. These servers store all the users' information (profile, contacts, contents, etc). Such an infrastructure incurs high operational and maintenance costs. Furthermore, this may threaten th...

BitTorrent is one of the most popular application in the current Internet. However, we still have little knowledge about the topology of real BitTorrent swarms and how the traffic is actually exchanged among peers. This paper addresses fundamental questions regarding the topology of live BitTorrent swarms. For this purpose we have collected the evo...

BitTorrent is the most successful peer-to-peer application. In the last years the research community has studied the BitTorrent ecosystem by collecting data from real BitTorrent swarms using different measurement techniques. In this article we present the first survey of these techniques that constitutes a first step in the design of future measure...

Twitter is one of the most used applications in the current Internet with more than 200M accounts created so far. As other large-scale systems Twitter can obtain enefit by exploiting the Locality effect existing among its users. In this paper we perform the first comprehensive study of the Locality effect of Twitter. For this purpose we have collec...

BitTorrent suffers from one fundamental problem: the long-term availability of content. This occurs on a massive-scale with 38% of torrents becoming unavailable within the first month. In this paper we explore this problem by performing two large-scale measurement studies including 46K torrents and 29M users. The studies go significantly beyond any...

In the current Internet picture more than 70% of the hosts are located behind Network Address Translators (NATs). This is not a problem for the client/server paradigm. However, the Internet has evolved, and nowadays the largest portion of the traffic is due to peer-to-peer (p2p) applications. This scenario presents an important challenge: two hosts...

BitTorrent is the most popular P2P content delivery application where individual users share various type of content with tens of thousands of other users. The growing popularity of BitTorrent is primarily due to the availability of valuable content without any cost for the consumers. However, apart from required resources, publishing (sharing) val...

[Invited Talk] Eighth International Conference on Wired/Wireless Internet Communications (June 1-3, Luleå, Sweden) This paper addresses the topic of Fair QoE measurements in networking. The research of new solutions in networking is oriented to improve the user experience. Any application or service can be im- proved and the deployment of new solut...

In this paper, we report on the results of experiments with an implementation of H-P2PSIP, which allows the exchange of information among different DHTs (Distributed Hash Tables) making use of a hierarchical architecture. This paper validates our previous H-P2PSIP proposal in an environment with a real TCP/IP stack close to a real scenario. The res...

BitTorrent suffers from one fundamental problem: the long-term availability of content. This occurs on a massive-scale with 38% of torrents becoming unavailable within the first month. In this paper we explore this problem by performing two large-scale measurement studies including 46K torrents and 29M users. The studies go significantly beyond any...

Wireless technologies are rapidly evolving and the users are demanding the possibility of changing its point of attachment to the Internet (i.e. default router) without breaking the IP communications. This can be achieved by using Mobile IP or NEMO, however mobile clients must forward its data packets through its Home Agent (HA) in order to communi...

Video-on-demand (VoD) streaming has recently become a popular service on the Internet, with several companies offering videos to a global audience. However, traditional client/server based VoD streaming systems can be very bandwidth intensive and expensive ...

The IETF P2PSIP WG is currently standardising a protocol for distributed multimedia services combining the media session functionality of SIP and the decentralised distribution and localisation of resources in peer-to-peer networks. The current P2PSIP scenarios only consider the infrastructure for the connectivity inside a single domain. This paper...

A Hierarchical DHT Overlay Architecture based on P2PSIP is proposed to support a Skype-like service. The IETF P2PSIP Working Group is standardising a protocol to support any DHT in order to deploy services inside a domain. We extend its functionality to allow the interaction between peers of different domains. Furthermore, we perform an analysis of...

The evolution of the Internet is being leaded by two main threads, one driven by industry through the evolution of networking infrastructures and the other driven by producers of content either in a professional or non professional way. Moreover, due to the explosion of the World Wide Web (which has started as a document repository) and its success...

The scalability properties of DHT based overlay networks is considered satisfactory. However, in large scale systems this might still cause a problem since they have a logarithmic complexity depending. Further, they only provide a one dimensional structure and do not make use on inherent clustering properties of some applications (e.g. P2PVoIP or l...

We present OnMove, a protocol for content distribution in wireless delay tolerant networks for use by handheld de- vices. To improve content distribution, OnMove exploits so- cial characteristics (social similarities and physical en coun- ters) between individuals. We motivate the problem and de- scribe a content sharing protocol based on a ranking...

Having witnessed a rapid development of the digital media literacy in the modern society due to a multitude of technological advances in the low-cost photography, cinematography and 2D/3D graphic design, there is a proliferation of high quality media content generated, distributed and experienced by the end users. This phenomenon, known as the User...

Providing innovating multimedia services is a high priority for service providers. Due to the high traffic volume created by multimedia content, the use of decentralised services can lead to better solutions. Starting from the ongoing work of P2PSIP, we define a simple way to interconnect different domains using peer-to-peer networks. We define the ne...

Mobile IP and Network Mobility are the IETF proposals to obtain mobility. However, both of them have routing limitations, due to the presence of an entity (Home Agent) in the communication path. Those problems have been tried to be solved in different ways. A fam- ily of solutions tries to improve the routing by locating closer Home Agents making s...

This paper presents Bittella :an ew social network for content distribution based on Peer-to-Peer technologies. It exploits the common interests of the users in order to create social groups based on an algo- rithm called Ranking Algorithm. On the other hand, Bittella is deployed over a semantic-search based and unstructured p2p network, in spite o...

The combined effect of optical and wireless subnetworks in an hypothetical future scenario where core networks have evolved to the still prototype Optical Burst Switching (OBS) technology is an open research issue. This paper studies this hybrid scenario, in the particular case of 802.11 access, by reviewing the key aspects of OBS and 802.11 with a...

Mobility in packet networks has become a critical issue in the last years. Mobile IP and the network mobility basic support protocol are the IETF proposals to provide mobility. However, both of them introduce performance limitations, due to the presence of an entity (home agent) in the communication path. Those problems have been tried to be solved...

Search systems based on hierarchical taxonomies provide a specific type of search functionality that is not provided by conventional search engines. For instance, using a taxonomy, the user can look for documents related to just one of the categories of the taxonomy. This paper describes a hybrid data architecture that improves the performance of r...

This paper describes a complete demo sce-nario where a Triple Play configuration (video, audio and data) with quality of service will be shown. This scenario could be considered as the aim of the Next Generation Networks (NGN) where a unified network is used to transport all possible kind of traffic towards a broadband Ethernet access multi-provide...

Resumen Habitualmente se considera que un acceso de banda ancha que proporciona una gran capacidad de transmisión tanto a entornos de negocio como a entornos residenciales, es suficiente como para distribuir servicios avanzados de calidad. Sin embargo ni las redes de acceso están aún lo suficientemente evolucionadas como para soportar todo tipo de...

QoS management is nowadays a mandatory feature in current broadband residential gateways developments. The interconnection between different QoS domains has to be treated into different steps in order to provide a reliable end-to-end QoS solution. The scenario analyzed in this paper is the mapping between QoS requirements in residential users conne...

The need of efficient tools in order to manage, retrieve and filter the information in the WWW is clear. Web directories are taxonomies for the classification of Web documents. These kind of information retrieval systems present a specific type of search where the document collection is restricted to one area of the category graph. This paper intro...

Resumen QoS management is nowadays a mandatory feature in current broadband residential gateways developments. The interconnection between different QoS domains has to be treated into different steps in order to provide a reliable end-to-end QoS solution. The scenario analyzed in this paper is the mapping between QoS requirements for residential us...

In this paper we propose a new protocol for uns-tructured and semantic-searching based p2p networks: Bittella. It forms a three level overlay network: the lowest level is the unstructured p2p network (e.g. Gnutella). The medium level is formed by clusters per content, we call the resulting structure Small World per Content structure. This level all...

In this paper we propose a new protocol for uns-tructured and semantic-searching based p2p networks: Bittella. It forms a three level overlay network: the lower level is the unstructured p2p network (e.g. Gnutella). The medium level is formed by clusters per content, we call the resulting structure Small World per Content structure. This level allo...

Mobility in packet networks has become a critical issue in the last years. Mobile IP and NEMO are the IETF proposals to provide mobility. However, both of them introduce performance limitations, due to the presence of an entity, the Home Agent (HA), in the communication path. A family of solutions solves the problem by allowing mobile devices to us...

Residential Gateways (RGW) are the last (or rst, it depends on the point of view) element in the access network and the interface between Home Network and access provider. In MUSE [1] our work is related to the design of a RGW compliant with QoS requirements and to the development of a RGW prototype. In this paper we propose a new model to design R...

Resumen En este artículo se expondrá el trabajo llevado a cabo por los autores dentro del proyecto europeo MUSE, que tiene como misión crear un estándar europeo de redes de banda ancha que cumpla con los objetivos planteados para que llegue a la mayor parte de los ciudadanos de este continente, cumpla sus expectativas de alto rendimiento y sea econ...

This paper presents SwarmTella, a novel architecture for con- tent distribution in Community Scenarios. SwarmTella is a general framework allowing the distribution of contents of different type (file-sharing, VoD Distribution and Live Streaming). For this purpose, it uses delivery techniques based on swarming. On the other hand, the searching of co...

Nowadays DSL and cable are the two main access technologies used to bring real broadband Internet to the residential environment but in a near future, with the deployment of FTTH (Fiber To The Home), transfer rates will not be a problem anymore and one of the most important challenges will be located on the provisioning of QoS (Quality of Service)...

The Peer to Peer Home Agent Network is a novel overlay that allows to the Mobile Devices to discover a close HA among a set of them geographically distributed. The use of a close HA permits to reduce the delay in the communications between the Mobile Device and its Cor-respondent Nodes in Internet. This paper defines the main mechanism to make the...

El Gobierno de la Comunidad de Madrid, y en concreto su Dirección General de Universidades e Investigación, ha financiado la creación de una de las redes de investigación más avanzadas tecnológicamente de Europa: la Red Telemática de Investigación de Madrid, REDIMadrid, eligiendo a la Fundación Madri+d para el Conocimiento como la entidad responsab...

Proceedings of: The 6th Annual Mediterranean Ad Hoc Networking Workshop (Med Hoc Net 2007. (Corfu, Greece), June 2007 This work presents a study of searching mechanisms in Peer-to-Peer (p2p) networks. The aim of this research line is to analyse cross-searching mechanisms that will allow the hierarchical interconnection of p2p networks. A set of rel...

Proceeding of: VIII Jornadas de Ingeniería Telemática (JITEL '09), Universidad Politécnica de Cartagena, Cartagena, Murcia, 15-17 de septiembre de 2009 The use of peer-to-peer technologies is increasing everyday and the improvement of mobility technologies is a reality. Now, it is expected that peer-to-peer applications run on mobile devices, but t...