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Nozzilla: A Peer-to-Peer IPTV Distribution Service for an IMS-based NGN
Get PDFBest Paper AwardDuring the last years next generation networks
(NGNs) have gained attention, as an increasing number of
network operators moved toward triple-play services: telephony, Internet and IPTV. Unfortunately, from the service provider perspective, IPTV usually comes at a high cost in terms of equipment and/or necessary bandwidth. In this paper we propose Nozzilla, a peer-to-peer like video streaming service for an NGN based on the IP Multimedia Subsystem (IMS), which can be used by third-party IPTV service providers as a cost effective alternative
to IP multicast or content distribution networks. The service uses the residential gateways (NGN customer premises equipment) to create a streaming overlay using the remaining or a fixed amount of network bandwidth. Nozzilla takes advantage of the QoS and resource reservation enabled by a NGN to support multipledescription streaming that improves the perceived quality during temporary failures.TRUEpu
Speeding IPv6 Address Autoconfiguration for VANETs through Caching
Get PDFGeoSAC is a mechanism that enables IPv6 address autoconfigur ation in vehicular networks based on geographic routing. It is built using one of the most know networking stack
in the field of VANET, the one proposed by the car-to-car conso rtium. GeoSAC adapts the existing IPv6 stateless address autoconfiguration prot ocol to VANETs. In this thesis
we analytically model GeoSAC in order to evaluate its perfomance, especially in terms of configuration times. Then we propose an optimization for this protocol using router advertisement caching which has also been modeled. We validate both the model we proposed by means of simulation. Simulation results show that our optimization significantly improves the performance in terms of configuration time but also for si gnalling overhead.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
Failure Detection and Locator Pair Exploration Protocol for IPv6 Multihoming
No full textRFC 5534 specifies a protocol for detecting and repairing broken connectivity. It is used within Shim6, a mechanism to allow networks, including small ones such as home networks, to be connected to multiple internet service providers at the same time (multihoming), switching dynamically from one to the other if the connection over one ISP stops working. Shim6 is related to efforts to make internet routing more scalable as it avoids the existing multihoming mechanism where the routing system takes on additional work. draft-van-beijnum-shim6-shim6to4 is a proposed extension to Shim6 that would also work with IPv4 to some degree.This document specifies how the level 3 multihoming Shim6 protocol (Shim6) detects failures between two communicating nodes. It also specifies an exploration protocol for switching to another pair of interfaces and/or addresses between the same nodes if a failure occurs and an operational pair can be found.Network Working GroupIETFpu
A Control Theoretic Approach for Throughput Optimization in IEEE 802.11e EDCA WLANs
Get PDFTheMAC layer of the 802.11 standard, based on the CSMA/CA mechanism, specifies a set of parameters to control the aggressiveness of stations when trying to access the channel. However, these parameters are statically set independently of the conditions of the WLAN (e.g. the number of contending stations), leading to poor performance for most scenarios.
To overcome this limitation previous work proposes to
adapt the value of one of those parameters, namely the
CW, based on an estimation of the conditions of the
WLAN. However, these approaches suffer from two major drawbacks: i) they require extending the capabilities
of standard devices or ii) are based on heuristics.
In this paper we propose a control theoretic approach
to adapt the CW to the conditions of the WLAN, based on an analytical model of its operation, that is fully compliant with the 802.11e standard. We use a Proportional Integrator controller in order to drive the WLAN to its optimal point of operation and perform a theoretic analysis to determine its configuration. We show by means of an exhaustive performance evaluation that our algorithm maximizes the total throughput of the WLAN and substantially outperforms previous standard-compliant proposals.TRUEpu
Network Traffic Reduction in Six Degree-of-Freedom Haptic Telementoring Systems
Get PDFThis paper introduces a haptic data reduction and
transmission technique to reduce the packet rate in six Degreeof-Freedom (6-DoF) haptic-enabled telementoring systems. The
presented method relies on the limitations of human haptic
perception (i.e. the Just Noticeable Differences) with respect
to a user’s hand position and orientation in order to reduce
the number of packets transmitted without compromising
transparency. A haptic prediction model is exploited to further
reduce the amount of haptic packets transmitted, and to
improve the reconstruction of data samples on the receiver
side. Several distance metrics are also discussed to evaluate
the acuity of human haptic perception when data reduction
is performed in 6-DoF settings. Psychophysical experiments
validate the effectiveness of the suggested algorithm as great
haptic data reduction is achieved (up to 96%), while preserving
the overall quality of the telementoring environment.TRUEpu
A CARMEN mesh experience: deployment and results
Get PDFWhen there is no wired connectivity, wireless mesh networks
(WMNs) can provide Internet access with lower cost
and greater flexibility than traditional approaches. This has motivated the design of new protocols and algorithms for
WMNs, and recently the deployment of experimental prototypes.
In this paper we add to these previous works with
the performance evaluation of a first CARMEN deployment,
with the following distinguishing features: i) it is an indoor deployment, ii) it is used by real users to connect to the Internet, and iii) it is built using off-the-shelf hardware. The results show that mesh technology can provide users with a satisfactory Internet experience, and motives further research along this line.TRUEpu
Router buffer sizing
No full textAt the summer 2009 IETF meeting in Stockholm, there were discussions about establishing a HOMEGATE working group that would create specifications or recommendations about home gateways that are used to connect home users to the internet. One issue relevant to HOMEGATE and also to the LEDBAT working group is the delay caused by buffering packets in home gateways. A short presentation highlighted this issue as a means to initiate work on limiting
the harmful effects.IETFpu
FLaCoSt: A Novel Peer to Peer Architecture for Video Streaming in a Next Generation Network
Get PDFThis paper proposes a peer-to-peer video streaming
delivery system within the framework of Next Generation
Networks using Application Level Multicast. Increased efficiency and reliability is achieved in two ways. First, the system uses path diversity by splitting the video traffic in several stripes and distributing each stripe via different multicast trees. Second, the proposed architecture lies within a Next Generation Network framework that enables network resource reservations with different classes of service. Therefore, the video stripes can receive different priorities making possible the usage of Layered Coding techniques such as Multi-Description Coding and Scalable Video Coding. The peer-topeer
protocol takes advantage of the multipath delivery and
resources reservation by optimising the searches for a parent in the multicast tree, thus minimising the service access time and service interruptions. These ideas can be improved using always-on central devices like Residential Gateways as peer nodes.TRUEpu
Knowledge management in biomedical libraries: A semantic web approach
Get PDFIn recent years, technological advances in highthroughput
techniques and efficient data gathering methods, coupled with a world-wide effort in computational biology, have resulted in an enormous amount of life science data available in repositories devoted to biomedical literature.
These repositories lack the ability to attain an effective and accurate search. Using semantic technologies as the key for interoperation enables searching and processing of biomedical literature in a more efficient way. However, emerging semantic applications take for granted specific knowledge that biomedical researchers may not have. This paper presents design principles for easy-to-use biomedical
semantic applications by means of ontology-based annotations
and faceted search. The proposed approach is backed with a usable prototype that shows the breakthroughs of adding these principles to a biomedical digital library where identifying and searching information are critical aspects for non-semantic Web experts.TRUEpu