Abstract-Greening the communication protocols is nowadays recognized as a primary design goal of future global network infrastructures. The objective function for optimization is the amount of information transmitted per unit of energy, replacing the amount of information transmitted per unit of time (i.e., throughput). In this paper we investigate the case of IEEE 802.11- based WLANs and first show that, given the existing diversity of power consumption figures among mobile devices, performing a fair allocation of resources among devices is challenging. We then propose a criterion to objectively balance between the most energy-efficient configuration (where all resources are given to the single most energy efficient device) and the throughput-optimal allocation (where all devices evenly share the resources regardless of their power consumption).

Ponente: Iljitsch van Beijnum, Ayudante de Investigación, Institute IMDEA Networks Lugar: Aula 4. 1F03, Departamento de Telemática, Edificio Torres Quevedo, Universidad Carlos III de Madrid, Avda. Universidad, 30, 28911 Leganes – Madrid Fecha: 25 de mayo 2011, 13:00 Organización: NETCOM Research Group (Departamento de Telemática, Universidad Carlos III de Madrid, España); Institute IMDEA Networks (Madrid, España)   El seminario se impartirá en inglés

Game theoretical techniques have recently become prevalent in a wide range of engineering applications, notably, in wireless and communication networks. With the emergence of novel networking paradigms such as cognitive radio or cooperative communications and the need for self-organizing and decentralized networks, it has become imperative to seek game theoretical tools that allow studying and analyzing the interactions of the nodes in future communication networks. In this talk, following a brief overview on the fundamentals and potential of game theory, we put a particular emphasis on coalitional game theory, which is a branch of game theory that deals with cooperative behavior.

Institute IMDEA Networks annually holds a by-invitation-only thematic workshop in Madrid. The workshop accompanies a meeting of our Scientific Council comprised by prominent researchers. In addition to talks by Scientific Council members, the workshop includes invited talks by external experts in the research theme of the workshop. The 2011 workshop theme is Internet science with a focus on social networking.

The technological advancement and information overload in recent years increased the popularity of Distributed Storage Systems where the data is replicated and maintained at multiple disks or servers residing at different network locations. While replication is sufficient to ensure data survivability, it raises an important question: "How can we efficiently maintain consistency among the replicas, despite system asynchrony and failures?"  

BitTorrent is currently the dominant Peer-to-Peer (P2P) protocol for file-sharing applications. BitTorrent is also a nightmare for ISPs due to its network agnostic nature, which is responsible for high network transit costs. The research community has deployed a number of strategies for BitTorrent traffic localization, mostly relying on the communication between the peers and a central server called tracker. However, BitTorrent users have been abandoning the trackers in favor of distributed tracking based upon Distributed Hash Tables (DHTs).    

Efficient vehicle-to-Internet routing and address autoconfiguration are two of the missing pieces required to provide Internet connectivity from vehicles. Here, we propose TREBOL, a tree-based and configurable protocol which benefits from the inherent tree-shaped nature of vehicle to Internet traffic to reduce the signaling overhead while dealing efficiently with the vehicular dynamics.

The amount of redundant paths among ASes has dramatically increased throughout the Internet. Unfortunately, the unipath nature of BGP constrains border routers to course traffic across a single path at a time. Although, multipath inter- domain routing is able to provide richer routing configurations, the lack of incentives to replace BGP as inter-domain routing protocol implies that multipath solutions must be backwards compatible with BGP.

Energy efficiency is one of the great technological challenges of our times. Recently, the concerns for the environmental consequences of the huge rate with which energy is consumed is leading to the awareness that electricity consumption and waste should be reduced in all sectors. The ICT (Information and Communication Technology) sector makes no exception, since it is becoming a major component of the worldwide energy consumption budget.  

In the last decade, there have been radical changes in both the nature of the mechanisms used for Internet content distribution, and the type of content delivered. On the one hand, Peer-to-Peer (P2P) based content distribution has matured. On the other hand, there has been a tremendous growth in video traffic. The goal of my work is to characterize these emerging trends in content distribution and understand their implications for Internet Service Providers (ISP) and users. Such characterization is critical given the predominance of P2P and video traffic in the Internet today and can enable further evolution of content delivery systems in ways that benefit both providers and users.