A substantial amount of work has recently gone into localizing BitTorrent traffic within an ISP in order to avoid excessive and often times unnecessary transit costs. Several architectures and systems have been proposed and the initial results from specific ISPs and a few torrents have been encouraging. In this work we attempt to deepen and scale our understanding of locality and its potential. Looking at specific ISPs, we consider tens of thousands of concurrent torrents, and thus capture ISP-wide implications that cannot be appreciated by looking at only a handful of torrents. Secondly, we go beyond individual case studies and present results for the top 100 ISPs in terms of number of users represented in our dataset of up to 40K torrents involving more than 3.9M concurrent peers and more than 20M in the course of a day spread in 11K ASes. We develop scalable methodologies hat permit us to process this huge dataset and answer questions such as: What is the minimum and the maximum transit traffic reduction across hundreds of ISPs? What are the win-win boundaries for ISPs and their users? What is the maximum amount of transit traffic that can be localized without requiring fine-grained control of inter-AS overlay connections? What is the impact to transit traffic from upgrades of residential broadband speeds?

Existing Swarm-based Peer-to-Peer Streaming (SPS) applications rely on a randomly connected overlays among peers, which tend to generate a significant amount of costly inter-ISP traffic. To reduce such traffic, localization of overlay connectivity within each ISP has received a great deal of attention as a promising approach for reducing the volume of inter-ISP traffic.

Ponentes: Dr. Sergey Gorinsky (Senior Researcher, IMDEA Networks) Prof. Dr. Arturo Azcorra (Director General de Transferencia de Tecnología y Desarrollo Empresarial (Ministerio de Ciencia e Innovación) Paul Patras (Research Assistant, IMDEA Networks) Dr. Mary Luz Mouronte (Division Manager, Telefonica Research, Madrid) Dr. Albert Banchs (Deputy Director, IMDEA Networks; Profesor Titular, UC3M) Prof. Dr. Narasimha Reddy (Cátedra de Excelencia, Universidad Carlos III de Madrid; Visiting Researcher, IMDEA Networks, Madrid; Texas A&M University, USA) Alejandro Javier Tosina González (Representante español en ICT Committee – EU Framework Programme; CDTI – Ministerio de Ciencia e Innovación) Localización: Sala de Audiovisuales, Sala 3.1.S08, Edificio Rey Pastor (Biblioteca), Universidad Carlos III de Madrid, Avda. Universidad, 30, 28911 Leganés – Madrid. Fecha: 11 de Noviembre, 2009, 15:00 – 18:00. Organización: IMDEA Networks en colaboración con la Escuela Politécnica Superior, Universidad Carlos III de Madrid, Campus de Leganés. La conferencia se impartirá en Inglés. Registro previo: rebeca.demiguel imdea.org

The way the Internet works today is that routing protocols select a single path through the network, and transport protocols like TCP then adapt to the properties of that path. So the situation where there are unused paths that remain idle is quite common. The idea behind multipath TCP is to modify TCP so it can send packets over multiple paths at the same time, moving traffic from more congested paths to less congested paths and thus optimizing network utilization and performance.

This talk gives an overview on how different overlay networks can share information among them and some recent results based on an implementation tested on an emulation environment are given.

Interest in underwater acoustic networking research has grown rapidly in the past few years. Fundamental differences between underwater acoustic propagation and terrestrial radio propagation call for new criteria for the design of communications systems and networking protocols. In this talk, we will provide an overview of the main challenges posed by the underwater acoustic propagation environment, with special emphasis on networking and protocol design issues, and provide novel insights that are useful in guiding both protocol design and network deployment. We will then address in more detail some specific examples of how the unique features of underwater propagation and acoustic modems affect protocol design. In particular, we will (1) focus on the energy consumption profile of acoustic modems and its impact on the design of topology control mechanisms and on the trade-off between sleep cycles and wake-up modes, and (2) present a novel energy-efficient routing protocol for underwater networks that explicitly accounts for the relationship between hop distance, bandwidth, and energy consumption.

The peer-to-peer paradigm shows the potential to provide the same functionality like client/server based systems, but with much lower costs. One substantial limitation of p2p systems are missing guarantees on the quality of service, as the whole infrastructure is based on unreliable peers. In order to control the quality of peer-to-peer systems, monitoring and management mechanisms need to be applied. Both tasks are challenging in large-scale networks with autonomous, unreliable nodes.

According to most technology pundits, progress in wireless and sensor networks will lead us into a world of ubiquitous computing, in which myriads of tiny, untethered sensors and actuators will communicate with each other. Information technology will thus deliver its most encompassing and pervasive accomplishment to mankind, promptly taking care of the needs and wishes of everyone.

Mobile communications networks have been evolved through multiple technologies over a period of several decades, to a stage that they become very complicated in the context of resource control and management. The heterogeneous next generation mobile network (NGMN) now includes a variety of network technologies and topologies incorporating with one another to provide a wide range of services; operate in a variety of channel conditions and environments; and within a single universal end user device. NGMN will need to be offered as an integrated system, and to promote interoperability among networks, offer global coverage and seamless mobility, enable the use of a universal handheld terminal, and enhance service quality compared to current wired networks. NGMN will be the infrastructure of the true mobile Internet.