The concept of Content Networks (CN) has extended Content Distribution Network (CDN) research in order to also comprise other aspects beyond delivery optimization. One central element of this research is the recognition that users are ultimately interested in the content (or a piece of information) and not any specific copy. This resulted in research on content addressing that allows general content access, i.e., the goal is retrieving content (or information) rather than routing of packets between end hosts. This is called Content-Centric respectively Information-Centric Networking (CCN/ICN). For some time these concepts have been explored for the better provision of and access to content services.
Seguir leyendo arrow_right_altThe delivery of live video streams over the plain old best-effort Internet is a major challenge. This talk deals with the issue of under-provisioning in the main delivery platforms, i.e. when the equipments that are in charge of delivering the video do not have enough upload capacity to serve all clients. In general, Content Delivery Networks (like Akamai) make a good job in ensuring large-scale delivery of the most popular streams through edge-servers that are located close to the clients.
Seguir leyendo arrow_right_altInterest 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.
Seguir leyendo arrow_right_altThis presentation intends to extract some useful hints on how to successfully manage an internationalisation process. It is focused on the specific case of a Spanish very large company: Telefónica, the leading Spanish telecommunications operator and one of the Top Ten telcos in the worldwide ranking by market cap nowadays.
Seguir leyendo arrow_right_altNowadays users expect to experience highly dependable network connectivity and services. However, several recent episodes demonstrate that software errors and operator mistakes continue to cause undesired disturbances and outages. Software-defined networking (SDN) is a new kind of network architecture that decouples the control plane from the data plane - a vision currently embodied in OpenFlow. By logically centralizing the control-plane computation, SDN provides the opportunity to remove complexity from and introduce new functionality in our networks. On the other hand, as the network programmability enhances, risks arise that buggy software in network controllers may disrupt an entire network.
Seguir leyendo arrow_right_altThe placement of regenerators in optical networks has become an active area of research during the last years. Given a set of lightpaths in a network G and a positive integer d, regenerators must be placed in such a way that in any lightpath there are no more than d hops without meeting a regenerator. In the talk I present a few optimization problems that arise within this framework.
Seguir leyendo arrow_right_altAuctions have regained interest from researchers due to its different new applications (Google AdWords auctions, cloud computing auctions, privacy auctions, and white spaces spectrum auctions). In this work in particular we explore auctions for spectrum that can be allocated either to a single bidder (for licensed use) or to a collection of bidders (for unlicensed use).
Seguir leyendo arrow_right_altWhile a considerable amount of research has been devoted to peer-to-peer backup and storage, no such system actually became widely adopted in the wild. My take on this is that there is the opportunity to build better, and possibly more successful, systems: while some design issues (e.g., erasure coding and data indexing) have been well explored, others have been barely scratched.
Seguir leyendo arrow_right_altMobile devices are energy-limited. Both industry and the research community proposed solutions to overcome these limitations with relative success at different levels such as hardware, operating system and even applications.
Seguir leyendo arrow_right_altAutonomous, self-configuring multihop networks present a versatile solution to provide broadband services with infrastructure-less deployments and decentralized management. Furthermore, their intrinsic adaptability and resilience can be enhanced with cognitive radio technology, enabling the nodes of the network to adjust their transmitting parameters to the specific operational environment.
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