IMDEA Networks Institute Digital Repository
Not a member yet
1915 research outputs found
Sort by
ADD-PATH for Route Servers
No full textNetwork Working Group
Internet-Draft
Expires: August 11, 2014
http://tools.ietf.org/html/draft-francois-idr-rs-addpaths-00BGP speakers in Internet Exchange Points exchange routes with a large number of peers. To reduce the burden of maintaining many sessions, IXPs implement and administrate BGP route servers. Route servers announce to their clients the paths of multiple peers by using a single eBGP session. Route servers, however, are restricted to propagating a single path per NLRI per eBGP session. This constraint affects the path diversity received by clients, which could use paths that they would not have chosen, had they known all possible paths. To overcome this limitation, we propose in this draft the extension of ADD-PATH to eBGP peers in the context of route servers.pu
Graph-based Techniques for Topic Classification of Tweets in Spanish
Get PDFTopic classification of texts is one of the most interesting challenges in Natural Language Processing (NLP). Topic classifiers commonly use a bag-of-words approach, in which the classifier uses (and is trained with) selected terms from the input texts. In this work we present techniques based on graph similarity to classify short texts by topic. In our classifier we build graphs from the input texts, and then use properties of these graphs to classify them. We have tested the resulting algorithm by classifying Twitter messages in Spanish among a predefined set of topics, achieving more than 70% accuracy.pu
A First Implementation and Evaluation of the IEEE 802.11aa Group Addressed Transmission Service
Get PDFThe IEEE 802.11aa Task Group has recently standardized a set of mechanisms to efficiently support video multicasting, namely, the Group Addressed Transmission Service (GATS). In this article, we report the implementation of these mechanisms over commodity hardware, which we make publicly available, and conduct a study to assess their performance under a variety of real-life scenarios. To the best of our knowledge, this is the first experimental assessment of GATS, which is performed along three axes: we report their complexity in terms of lines of code, their effectiveness when delivering video traffic, and their efficiency when utilizing wireless resources. Our results provide key insights on the resulting trade-offs when using each mechanism, and paves the way for new enhancements to deliver video over 802.11 Wireless LANs.pu
Graceful Convergence in Link-State IP Networks: A Lightweight Algorithm Ensuring Minimal Operational Impact
Get PDFThe use of real-time multimedia or mission-critical applications over IP networks puts strong pressure on service providers to operate disruption-free networks. However, after any topological change, link-state Interior Gateway Protocols (IGPs), such as IS-IS or OSPF, enter a convergence phase during which transient forwarding loops may occur. Such loops increase the network latency and cause packet losses. In this paper, we propose and evaluate an efficient algorithm aimed at avoiding such traffic disruptions without modifying these IGPs. In case of an intentional modification of the weight of a link (e.g., to shut it down for maintenance operations or to perform traffic engineering), our algorithm iteratively changes this weight, splitting the modification into a sequence of loop-free transitions. The number of weight increments that need to be applied on the link to reach its target state is minimized in order to remain usable in existing networks. Analysis performed on inferred and real Internet service provider (ISP) topologies shows that few weight increments are required to handle most link shutdown events (less than two intermediate metrics for more than 85% of the links). The evaluation of our implementation also reveals that these minimal sequences can be computed in a reasonable time.pu
UC3M: inHome NAT detection
No full textFirst presentation of NATalyser. Project Leone (From global measurements to local management): http://leone-project.eu/.TRUEpu
A multiple stack architecture for intelligent vehicles
No full textDOI: http://dx.doi.org/10.1109/IVS.2014.6856604We present a general architecture for intelligent vehicles, especially collaborative driving applications. Intelligent vehicles are similar to communication networks as both types of systems interact with physical world using devices that are rapidly evolving, while intelligent vehicles are more complicated than communication network because they interact with the physical world in not only, one but several ways, and because many of the interactions have severe time constraints. The proposed architecture adopts multiple layered stack structures to address the issues. We also present a collaborative merge protocol as an instantiation of the proposed architecture, and discuss the advantage of the architecture in terms of the feasibility of model checking and conformance testing.TRUEpu
Micro Aerial Vehicle Networks: An Experimental Analysis of Challenges and Opportunities
Get PDFSeries on Ad Hoc And Sensor Networks of the IEEE Communication Magazine.The need for aerial networks is growing with the recent advance of micro aerial vehicles (MAVs), which enable a wide range of civilian applications. Our experimental analysis shows that wireless connectivity among MAVs is challenged by the mobility and heterogeneity of the nodes, light-weight antenna design, body blockage, constrained embedded resources, and limited battery power. Yet, the movement and location of MAVs are known and may be controlled to establish wireless links with best transmission opportunities in time and space. This special ecosystem undoubtedly requires a rethinking of wireless communications and calls for novel networking approaches. Supported by empirical results, we identify important research questions and introduce potential solutions and directions for investigation.pu
Routing in a Fleet of Micro Aerial Vehicles: First Experimental Insights
Get PDFMicro aerial vehicles (MAVs) have the potential to support civilian applications in large areas by providing an ad-hoc multi-hop wireless network. Yet, available network routing protocols have not been designed for the micro aerial use case and it is unclear how well they can cope in practice with the wireless link and topology dynamics posed by MAVs. To answer this question, we provide a first assessment of major ad-hoc routing protocols in a lab study. Further, we present measurement results for B.A.T.M.A.N. and greedy geographical routing in a small IEEE 802.11n MAV testbed and discuss potential directions for future research.TRUEpu
Understanding the Reachability of IPv6 Limited Visibility Prefixes
No full textThe main functionality of the Internet is to provide global connectivity for every node attached to it. In light of the IPv4 address space depletion, large networks are in the process of deploying IPv6. In this paper we perform an extensive analysis of how BGP route propagation affects global reachability of the active IPv6 address space in the context of this unique transition of the Internet infrastructure. We propose and validate a methodology for testing the reachability of an IPv6 address block active in the routing system. Leveraging the global visibility status of the IPv6 prefixes evaluated with the BGP Visibility Scanner, we then use this methodology to verify if the visibility status of the prefix impacts its reachability at the interdomain level. We perform active measurements using the RIPE Atlas platform. We test destinations with different BGP visibility degrees (i.e., limited visibility - LV, high visibility - HV and dark prefixes). We show that the IPv6 LV prefixes (v6LVPs) are generally reachable, mostly due to a less-specific HV covering prefix (v6HVP). However, this is not the case of the dark address space, which, by not having a covering v6HVP is largely unreachable. When talking about the results we present in this paper a better explanation of trace route and some basic concepts of BGP will be provided.FALSEpu
Demo: LabVIEW based framework for prototyping dense LTE networks
Get PDFhttp://dx.doi.org/10.1145/2643230.2643247In the demo, we illustrate the integration aspects of LTE testbed using LabVIEW SISO OFDM Physical layer and open source NS-3 LTE LENA stack. We leverage the NS-3 LENA module, which allows researchers to conduct simulations by emulating large network of base-stations, mobile devices and core network. However, the validity of results produced from such simulations is limited due to the physical layer model and may not accurately reflect the true behavior of densely-deployed LTE networks. Hence, we implemented selected LTE physical channels in LabVIEW to facilitate more realistic emulation of the LTE testbed and integrate it with MAC/higher layers of LENA protocol stack. The main goal of the testbed is to be able to show the artifacts caused in interference limited environment and demonstrate the performance of Enhanced Inter-cell Interference Coordination (eICIC) algorithms proposed by researchers in 3GPP. This demo shows preliminary results and we plan to use this testbed to showcase different aspects of Software Defined Networking (SDN) framework which is used to fine-tune different aspects of dense deployments within EU FP7 CROWD research project.TRUEpu