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Separating Wheat from Chaff: Winnowing Unintended Prefixes using Machine Learning
Get PDFIn this paper, we propose the use of prefix visibility at
the interdomain level as an early symptom of anomalous events in the Internet. We focus on detecting anomalies which, despite their significant impact on the routing system, remain concealed from state of the art tools. We design a machine learning system to winnow the prefixes with unintended limited visibility – symptomatic of anomalous events – from the prefixes with intended limited visibility – resulting from legitimate routing operations.
We train a winnowing algorithm with ground-truth data on 20,000 operational limited visibility prefixes (LVPs) already classified by the operators of the origin networks. The ground-truth was collected using the BGP Visibility Scanner, a tool we developed to provide operators with a multi-angle view on the efficacy of their routing policies. We build a dataset with the pre-classified prefixes
and the features describing their visibility status dynamics. We further use this dataset to derive a boosted decision tree which winnows unintended LVPs with an accuracy of 95%.TRUEpu
On the State of Interdomain Routing in Africa
Get PDFWith IP networking booming on the African continent, initiatives to promote BGP peering in the region emerge, and changes in the transit behavior of ISPs serving Africa are expected. However, there is little knowledge on the IP transit topology currently forming the African Internet. Enhancing the RIPE Atlas measurement infrastructure, we shed light on both v4 and v6 topologies interconnecting ISPs based on the continent. We deployed 21 RIPE Atlas probes in 15 ASes located in 11 African countries, and performed measurements among a total of 214 probes scattered throughout the con- tinent. Our results emphasize the dominance of ISPs based outside Africa for the provision of intra-continental paths, as well as the impact of this aspect on AS path length and end-to-end delay. They also reveal that South Africa is being adopted as a hub, thanks to its well connected infrastructure. We show a large variety of transit habits, depending on factors such as the language, the currency or the geographic location of the ISP. We finally highlight the emergence of new IXPs in Africa.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
Practical Interference Alignment in the Frequency Domain for OFDM-based Wireless Access Networks
Get PDFDOI: http://dx.doi.org/10.1109/WoWMoM.2014.6918922Interference alignment(IA)is often considered in the spatial domain in combination with MIMO systems.In contrast, aligning interference in the frequency domain among multiple subcarriers can also benefit single-antenna OFDM-based access networks. It allows for flexible operation on a per-subcarrier basis. We investigate the achievable by frequency IA in practice for a scenario with multiple access points and clients. Previous work is predominantly theoretical and focuses on idealized cases where all nodes have the same average signal-to-noiseratio(SNR). On the contrary, in practical networks, nodes typically have heterogeneous SNRs depending on channel conditions, which might have a significant impact on IA performance. We tackle this problem by designing mechanisms that adaptively choose which nodes shall perform IA on which subcarriers depending on current channel conditions. We implement and validate our approach on software-defined radios. To the best of our knowledge, this is the first practical implementation of IA in the frequency domain. Our measurements show that (1) frequency IA is feasible in practice, and (2) choosing appropriate nodes and subcarriers overcomes the main limitations due to heterogeneous SNRs. Our mechanisms enable IA in scenarios where it would be infeasible otherwise, achieving throughput gains close to the 33% theoretical maximum.TRUEpu
Segment Routing Use Cases
Get PDFSegment Routing (SR) leverages the source routing and tunneling paradigms. A node steers a packet through a controlled set of instructions, called segments, by prepending the packet with an SR header. A segment can represent any instruction, topological or service-based. SR allows to enforce a flow through any topological path and service chain while maintaining per-flow state only at the ingress node of the SR domain.
The Segment Routing architecture can be directly applied to the MPLS dataplane with no change on the forwarding plane. It requires minor extension to the existing link-state routing protocols. Segment Routing can also be applied to IPv6 with a new type of routing extension header.pu
Which Infrastructure for a better Internet in Africa ?
No full text27 participants were invited to this seminar and the full report has been edited by Crowcroft et al., published as part of the periodical Dagstuhl Reports (see http://www.dagstuhl.de/dagrep) and is available at http://dx.doi.org/10.4230/DagRep.4.11.78Reasons for low penetration and low quality of Internet access in Africa are numerous: high Internet access costs inherent to energy instability, transit costs, network operation costs, lack of infrastructure in rural areas, lack of content in Africa, as well as the preference of users for popular Google, Facebook or Youtube content mostly hosted outside Africa which lead to a constant loop (no local content no peering, no peering no local content). We review approaches to tackle this problem. We suggest a better energy provision to the industry (by Africans governments or private companies) which could be boosted by competition in this sector, an orientation of electrification politics towards solar energy storage and furniture, renewable energy, gas and nuclear centrals, as well as the establishment of a climate of fairness and cooperation/partnership by the regulations in the telecoms market. Most importantly, ISPs could increase peering to save on transit costs. They could also implement traffic engineering and efficient routing to keep local traffic local. Meanwhile, ISPs should invest in terrestrial optical fiber networks deployment or alternative technologies for the middle mile in order to reach more customers. Creation, development of local content and web content hosting should also be encouraged. Considerable efforts are currently being done on the continent to achieve these objectives but they need to be multiplied, as Africa is massive.FALSEpu
Design and practical deployment of a network-centric remotely piloted aircraft system
Get PDFRemotely piloted aircraft systems (RPASs) are gaining more are more relevance during the last decade since more applications are being enabled by lighter planes with increasing autonomy, higher ceilings, and more powerful transmission technologies. The integration of the RPAS as part of network-centric warfare would be a very important milestone to achieve because of the huge amount of information and capabilities that all these aircrafts can incorporate into the global scheme. This integration is easier for handheld (short-range) RPASs since their communications are typically based on digital transmission like WiFi or WiMAX, but it may not be as obvious for bigger RPASs (long-range, e.g., tactical or medium/high altitude systems) because their line of sight communications are frequently based on analog transmissions. This implies indirect integration into network-centric warfare by means of the ground control station (satellite communications, when available, may suffer notorious delay for certain applications). This article presents a recent practical experience, including flight test campaigns, deploying an all- IP communication architecture into one of the most relevant Spanish tactical RPASs, the SIVA, used by both the Spanish Army and the Spanish Air Force for the last 10 years. This deployment enables cost-effective integration of this RPAS (and its natural successor, the MILANO, a medium- altitude RPAS) into the network-centric warfare by means of direct TCP/IP transmissions over a long-range digital line of sight channel combined with satellite communications for beyond line of sight operations. The proposed design includes network-level security over the radio interfaces, automatic data link selection, support of remote video terminals, and access connectivity toward external IPv6 networks.pu
An Architecture for Software Defined Wireless Networking
Get PDFSoftware defined networking, characterized by a clear separation of the control and data planes, is being adopted as a novel paradigm for wired networking. With SDN, network operators can run their infrastructure more efficiently, supporting faster deployment of new services while enabling key features such as virtualization. In this article, we adopt an SDN-like approach applied to wireless mobile networks that will not only benefit from the same features as in the wired case, but will also leverage on the distinct features of mobile deployments to push improvements even further. We illustrate with a number of representative use cases the benefits of the adoption of the proposed architecture, which is detailed in terms of modules, interfaces, and high-level signaling. We also review the ongoing standardization efforts, and discuss the potential advantages and weaknesses, and the need for a coordinated approach.pu