The internet: A global telecommunications solution?

The provision and support of new distributed multimedia services are of prime concern for telecommunications operators and suppliers. Clearly, the potential of the latest Internet protocols to contribute communications components is of considerable interest to them. In this article we first review some of the new types of application and their requirements, and identify the need to support applications that have strict QoS requirements, the so-called critical applications. We review two proposals for enhancing the Internet service architecture. In addition to the integrated services work of the IETF, we look at the more recent proposals for differentiated services in the Internet. We then individually review recent protocol developments proposed to improve the Internet, and to support real-time and multimedia communications. These are IPv6 (the new version of the Internet Protocol), Resource reSerVation Protocol, and Multiprotocol Label Switching, respectively. In each case, we attempt to provide critical reviews in order to assess their suitability for this purpose. Finally, we indicate what the basis of the future infrastructure might be in order to support the full variety of application requirements

Implementing Network Virtualization for a Future Internet

Abstract — The Internet has become an essential communication medium upon which billions of people rely every day. However, necessary evolution of the Internet has been severely limited by reliability constrains and social-economic factors. Experts fear that current growth rates will threaten the future of the Internet as a whole, despite the fact that new core technologies already exist. Network virtualization presents a promising approach to overcome ossification and facilitate service deployment for a future Internet. Exploring this approach, we present a prototype implementation which realizes a subset of the 4WARD virtual network (VNet) architecture, allowing multiple VNets to coexist on top of a shared physical infrastructure. We discuss the functionality of our prototype and demonstrate experimental results to assess its performance. I

Combined use of geophysical methods and remote techniques for characterizing the fracture network of a potential unstable cliff site (the “Roche du Midi”, Vercors massif, France)

International audienceStability assessment of a cliff strongly depends on the fracture pattern and the face topography. Geological observations as well as classical geodetic measurements are difficult to perform on high nearly vertical cliffs like the ones surrounding the town of Grenoble (French Alps). In this study we combine remote and ground imaging techniques for characterizing the geometry and the fracture pattern of potential unstable cliff sites. A Dense Digital Surface Model (DDSM) of the rock face can now be obtained from laser scanning (Lidar) or photogrammetry. These techniques are safer and quicker than direct measurements. They offer the possibility to collect structural data and to sample the shape of the outcrop at a centimetric resolution. We applied these two techniques to a potential unstable site (the “Roche du Midi”, Vercors massif) for determining the main fracture families affecting the rock mass and we obtained results similar to direct measurements performed on the nearby outcrops and on the cliff face itself. The laser scanning data suffers a bias in the illumination of the site. Geophysical experiments were also conducted on the plateau and on the cliff face in order to delineate the fracture pattern inside the rock mass. ERT (Electrical Resistivity Tomography) and GPR (Ground Penetrating Radar) profiles were performed on the plateau and allowed near-vertical open fractures to be located in the vicinity of the surface. Best geophysical results in terms of penetration and resolution were however obtained from GPR profiles conducted directly on the cliff face. Laser scanning data were combined with GPR data in order to take into account the shape of the sampled profiles. The combination of vertical and short horizontal profiles allowed the strike and dip of the discontinuities to be determined. The two main families were imaged, as well as a major continuous inward dipping reflector which was not shown during the initial reconnaissance. Further investigation inside the mass effectively showed the existence of this fracture. These results highlight the power of the GPR technique in characterizing the discontinuity pattern inside rock mass for improving the model in view of hazard assessment

Flowstream Architectures

The Internet has seen a proliferation of specialized middlebox devices that carry out crucial network functionality such as load balancing, packet inspection or intrusion detection, amongst others. Traditionally, high performance network devices have been built on custom multi-core, specialized memory hierarchies, architectures which are well suited to packet processing. Recently, commodity PC hardware has experienced a move to multiple multi-core chips, as well as the routine inclusion of multiple memory hierarchies in the so-called NUMA architectures. While a PC architecture is obviously not specifically targeted to network applications, it nevertheless provides high performance cheaply. Furthermore, a few commodity switch technologies have recently emerged offering the possibility to control the switching of flows in a rather fine grained manner. Put together, these new technologies offer a new network commodity platform enabling new flow processing and forwarding at an unprecedented flexibility and low cost

Inner speech sustains predictable task switching: direct evidence in adults

It has been proposed that inner speech supports task selection in task-switching studies, especially when the need for endogenous control is increased. This has been established through the suppression of inner speech in cognitive-flexibility tasks that leads to poorer performance. The aim of this study is to quantify the role of inner speech in a flexibility task by using surface laryngeal electromyography, which, contrary to previous studies, enables participants to freely verbalise the tasks. We manipulated endogenous and exogenous flexibility in a mathematical switching task paradigm. Experiment 1 shows that inner speech acts as a support for switching and is recruited more often when the tasks are of an endogenous type. The main result of Experiment 2 that language is recruited more for the mixing cost than for the switch cost (regardless of the endogenous factor) extends past findings obtained through articulatory suppression

Towards Scalable and Affordable Content Distribution Services

peer reviewe

Securing Internet Coordinate System: Embedding Phase

This paper addresses the issue of the security of Internet Coordinate Systems, by proposing a general method for malicious behavior detection during coordinate computations. We first show that the dynamics of a node, in a coordinate system without abnormal or malicious behavior, can be modeled by a Linear State Space model and tracked by a Kalman filter. Then we show, that the obtained model can be generalized in the sense that the parameters of a filter calibrated at a node can be used effectively to model and predict the dynamic behavior at another node, as long as the two nodes are not too far apart in the network. This leads to the proposal of a Surveyor infrastructure: Surveyor nodes are trusted, honest nodes that use each other exclusively to position themselves in the coordinate space, and are therefore immune to malicious behavior in the system. During their own coordinate embedding, other nodes can then use the filter parameters of a nearby Surveyor as a representation of normal, clean system behavior to detect and filter out abnormal or malicious activity. A combination of simulations and Planet- Lab experiments are used to demonstrate the validity, generality, and effectiveness of the proposed approach for two representative coordinate embedding systems, namely Vivaldi and NPS

ISGRI: the INTEGRAL Soft Gamma-Ray Imager

For the first time in the history of high energy astronomy, a large CdTe gamma-ray camera is operating in space. ISGRI is the low-energy camera of the IBIS telescope on board the INTEGRAL satellite. This paper details its design and its in-flight behavior and performances. Having a sensitive area of 2621 cm$^2$ with a spatial resolution of 4.6 mm, a low threshold around 12 keV and an energy resolution of $\sim$ 8% at 60 keV, ISGRI shows absolutely no signs of degradation after 9 months in orbit. All aspects of its in-flight behavior and scientific performance are fully nominal, and in particular the observed background level confirms the expected sensitivity of 1 milliCrab for a 10$^6$s observation.Comment: INTEGRAL A&A special issu

Unikraft:Fast, Specialized Unikernels the Easy Way

Unikernels are famous for providing excellent performance in terms of boot times, throughput and memory consumption, to name a few metrics. However, they are infamous for making it hard and extremely time consuming to extract such performance, and for needing significant engineering effort in order to port applications to them. We introduce Unikraft, a novel micro-library OS that (1) fully modularizes OS primitives so that it is easy to customize the unikernel and include only relevant components and (2) exposes a set of composable, performance-oriented APIs in order to make it easy for developers to obtain high performance. Our evaluation using off-the-shelf applications such as nginx, SQLite, and Redis shows that running them on Unikraft results in a 1.7x-2.7x performance improvement compared to Linux guests. In addition, Unikraft images for these apps are around 1MB, require less than 10MB of RAM to run, and boot in around 1ms on top of the VMM time (total boot time 3ms-40ms). Unikraft is a Linux Foundation open source project and can be found at www.unikraft.or

LISP-DHT: Towards a DHT to map identifiers onto locators

peer reviewe