2,024 research outputs found

    IPv4 address sharing mechanism classification and tradeoff analysis

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    The growth of the Internet has made IPv4 addresses a scarce resource. Due to slow IPv6 deployment, IANA-level IPv4 address exhaustion was reached before the world could transition to an IPv6-only Internet. The continuing need for IPv4 reachability will only be supported by IPv4 address sharing. This paper reviews ISP-level address sharing mechanisms, which allow Internet service providers to connect multiple customers who share a single IPv4 address. Some mechanisms come with severe and unpredicted consequences, and all of them come with tradeoffs. We propose a novel classification, which we apply to existing mechanisms such as NAT444 and DS-Lite and proposals such as 4rd, MAP, etc. Our tradeoff analysis reveals insights into many problems including: abuse attribution, performance degradation, address and port usage efficiency, direct intercustomer communication, and availability

    Traversing NAT: A Problem

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    This quasi-experimental before-and-after study measured and analyzed the impacts of adding security to a new bi-directional Network Address Translation (NAT). Literature revolves around various types of NAT, their advantages and disadvantages, their security models, and networking technologies’ adoption. The study of the newly created secure bi-directional model of NAT showed statistically significant changes in the variables than another model using port forwarding. Future research of how data will traverse networks is crucial in an ever-changing world of technology

    Priority-Based Bandwidth Management in Virtualized Software-Defined Networks

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    In Industrial Internet of Things (IoT) applications, when the network size increases and different types of flows share the bandwidth, the demand for flexible and efficient management of the communication network is compelling. In these scenarios, under varying workload and flow priorities, the combined use of Software-Defined Networking (SDN) and Network Virtualization (NV) is a promising solution, as such techniques allow to reduce the network management complexity. This work presents the PrioSDN Resource Manager (PrioSDN_RM), a resource management mechanism based on admission control for virtualized SDN-based networks. The proposed combination imposes bounds on the resource utilization for the virtual slices, which therefore share the network links, while maintaining isolation from each other. The presented approach exploits a priority-based runtime bandwidth distribution mechanism to dynamically react to load changes (e.g., due to alarms). The paper describes the design of the approach and provides experimental results obtained on a real testbed

    A Multi-perspective Analysis of Carrier-Grade NAT Deployment

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    As ISPs face IPv4 address scarcity they increasingly turn to network address translation (NAT) to accommodate the address needs of their customers. Recently, ISPs have moved beyond employing NATs only directly at individual customers and instead begun deploying Carrier-Grade NATs (CGNs) to apply address translation to many independent and disparate endpoints spanning physical locations, a phenomenon that so far has received little in the way of empirical assessment. In this work we present a broad and systematic study of the deployment and behavior of these middleboxes. We develop a methodology to detect the existence of hosts behind CGNs by extracting non-routable IP addresses from peer lists we obtain by crawling the BitTorrent DHT. We complement this approach with improvements to our Netalyzr troubleshooting service, enabling us to determine a range of indicators of CGN presence as well as detailed insights into key properties of CGNs. Combining the two data sources we illustrate the scope of CGN deployment on today's Internet, and report on characteristics of commonly deployed CGNs and their effect on end users

    Analysis of security impact of making mShield an IPv4 to IPv6 converter box

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    NAT64/DNS64 in the Networks with DNSSEC

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    Zvyšuj?c? se pod?l resolverů a aplikac? použ?vaj?c? DNS-over-HTTPSvede k vyš?mu pod?lu klientů použ?vaj?c?ch DNS resolvery třet?chstran. Kvůli tomu ovšem selhává nejpouž?vanějš? NAT64 detekčn?metoda RFC7050[1], což vede u klientů použ?vaj?c?ch přechodovémechanismy NAT64/DNS64 nebo 464XLAT k neschopnosti tytopřechodové mechanismy správně detekovat, a t?m k nedostupnostiobsahu dostupného pouze po IPv4. C?lem této práce je navrhnoutnovou detekčn? metodu postavenou na DNS, která bude pracovati s resolvery třet?ch stran, a bude schopná využ?t zabezpečen? DNSdat pomoc? technologie DNSSEC. Práce popisuje aktuálně standardizovanémetody, protokoly na kterých závis?, jejich omezen?a interakce s ostatn?mi metodami. Navrhovaná metoda použ?vá SRVzáznamy k přenosu informace o použitém NAT64 prefixu v globáln?mDNS stromu. Protože navržená metoda použ?vá již standardizovanéprotokoly a typy záznamů, je snadno nasaditelná bez nutnostimodifikovat jak DNS server, tak s?t'ovou infrastrukturu. Protožemetoda použ?vá k distribuci informace o použitém prefixu globáln?DNS strom, umožňuje to metodě použ?t k zabezpečen? technologiiDNSSEC. To této metodě dává lepš? bezpečnostn? vlastnosti nežjaké vykazuj? předchoz? metody. Tato práce vytvář? standardizačn?bázi pro standardizaci v rámci IETF.The rising number of DNS-over-HTTPS capable resolvers and applicationsresults in the higher use of third-party DNS resolvers byclients. Because of that, the currently most deployed method of theNAT64 prefix detection, the RFC7050[1], fails to detect the NAT64prefix. As a result, clients using either NAT64/DNS64 or 464XLATtransition mechanisms fail to detect the NAT64 prefix properly,making the IPv4-only resources inaccessible. The aim of this thesisis to develop a new DNS-based detection method that would workwith foreign DNS and utilize added security by the DNS securityextension, the DNSSEC. The thesis describes current methods ofthe NAT64 prefix detection, their underlying protocols, and theirlimitations in their coexistence with other network protocols. Thedeveloped method uses the SRV record type to transmit the NAT64prefix in the global DNS tree. Because the proposed method usesalready existing protocols and record types, the method is easilydeployable without any modification of the server or the transportinfrastructure. Due to the global DNS tree usage, the developedmethod can utilize the security provided by the DNSSEC and thereforeshows better security characteristics than previous methods.This thesis forms the basis for standardization effort in the IETF.

    The Virtual Bus: A Network Architecture Designed to Support Modular-Redundant Distributed Periodic Real-Time Control Systems

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    The Virtual Bus network architecture uses physical layer switching and a combination of space- and time-division multiplexing to link segments of a partial mesh network together on schedule to temporarily form contention-free multi-hop, multi-drop simplex signalling paths, or 'virtual buses'. Network resources are scheduled and routed by a dynamic distributed resource allocation mechanism with self-forming and self-healing characteristics. Multiple virtual buses can coexist simultaneously in a single network, as the resources allocated to each bus are orthogonal in either space or time. The Virtual Bus architecture achieves deterministic delivery times for time-sensitive traffic over multi-hop partial mesh networks by employing true line-speed switching; delays of around 15ns at each switching point are demonstrated experimentally, and further reductions in switching delays are shown to be achievable. Virtual buses are inherently multicast, with delivery skew across multiple destinations proportional to the difference in equivalent physical length to each destination. The Virtual Bus architecture is not a purely theoretical concept; a small research platform has been constructed for development, testing and demonstration purposes
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