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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Talk Half Listen To Half: An Energy-Efficient Neighbor Discovery Protocol in Wireless Sensor Networks

Ravelo Suarez, Raudel 07 September 2018 (has links)
Due to the combination of constrained power, low duty cycle, and high mobility, neighbor discovery is one of the most challenging problems in wireless sensor networks. Existing discovery designs can be divided into two types: pairwise-based and group-based. The former schemes suffer from high discovery delay, while the latter ones accelerate the discovery process but increase transmission package size or incur too much energy overhead, far from practical. Guided by the Talk More Listen Less (TMLL) principle (published in 2016), in which beacons are not necessarily placed in the wakeup slots, we propose two different versions of a group-based protocol we called Talk Half Listen Half (THLH). For the first time, a group-based protocol uses the Channel Occupancy Rate (COR), one of the fundamental novel components of the TMLL model, for performance improvements, in the same way, Duty Cycle (DC) was used in previous group-based protocols. Both versions of the protocol use low transmission overhead in comparison with previous group-based discoveries. After analyzing pros and cons of each approach, we arrived at the conclusion that both behave the best for networks where the average number of new neighbors per slot (β) is low, a metric that sets the bases for performance comparisons of any current/future work with variable COR usage. We also derived a formula that links this new metric with the worst case avg. COR usage of our proposed protocols. Finally, simulation results show that our protocol can improve the average discovery latency and worst case latency close to 50% given low β values.
2

Bezpečné objevování sousedů / Secure Neighbor Discovery Protocol

Bezdíček, Lukáš January 2014 (has links)
This report deals with designing and implementing of a complete SEND protocol for operating systems GNU/Linux. The first part of the document contains a description of ND and SEND protocols. The second part of the document defines security threats connected with unsecured ND. The third part of the report describes a design and implementation of SEND protocol named sendd . Conclusion of the document is dedicated to a summary of accomplished results and information about future development of this project.
3

Säker grannupptäck i IPv6 / Secure Neighbor Discovery in IPv6

Huss, Philip January 2011 (has links)
The IPv6 protocol offers with some new functions, one of them is auto configuration. With auto configuration it is possible for nodes, i.e. hosts and routers, for automatically associated with IPv6 addresses without manual configuration. Auto configuration it is another protocol as it uses Neighbor Discovery protocol (ND) messages (ND is mandatory in the IPv6 stack). The main purpose of ND is that nodes can discover other nodes on the local link, perform address resolution, check that addresses are unique, and check the reachability with active nodes. There are exactly the same vulnerabilities of IPv6 as IPv4 and is now exception, ND if not properly secured. IPsec is a standard security mechanism for IPv6 but it does not solve the problem of secure auto configuration due the bootstrapping problem. Therefore the Internet Engineering Task Force (IETF) introduced Secure Neighbor Discovery (SEND). SEND is a mechanism for authentication, message protection, and router authentication. One important element of SEND is the use of Cryptographically Generated Address (CGA) an important mechanism to prove that the sender of the ND message is the actual owner of the address it claims NDprotector is an open-source implementation of SEND served as the basis for the analysis presented in this report. This implementation was evaluated in a small lab environment against some attacks in order to establish if it can defend itself from these attacks. / IPv6 protokollet kom det ett par nya funktioner där en av dem är autokonfiguration. Autokonfiguration gör det möjligt för noder, d.v.s. hostar och routrar för att automatiskt bli tilldelade IPv6 adresser manuell konfigurering. För att autokonfiguration ska fungera så används Neighbor Discovery (ND) meddelanden som är ett obligatoriskt protokoll i IPv6- stacken. ND har till huvudsaklig uppgift att noder kan upptäcka andra noder på den lokala länken, utföra adressöversättningar, kolltrollera så att adresser är unika samt kontrollera tillgängligheten hos aktiva noder. Precis som IPv4 så har IPv6 en hel del sårbarheter och med ND så är det inget undantag då det inte är säkrat. IPsec som är en den standard säkerhets mekanism till IPv6 löser inte problemet på grund av bootstrapping problemet. Det var därför Internet Engineering Task Force (IETF) introducerade Secure Neighbor Discovery (SEND). SEND är en mekanism för autentisering, meddelande skydd och router autentisering. En viktig del av SEND är Cryptographilcally Generated Address (CGA), en teknik som används för att försäkra sig så att det är den sändaren av ND meddelandet som är den riktiga ägaren av den hävdade adressen. NDprotector är en öppen källkods implementation av SEND som jag har valt att ha som grund för denna rapport. Jag kommer att sätta upp NDprotector i en liten labbmiljö där jag kommer att utföra olika attacker samt se efter om det klarar att försvara sig emot attackerna.
4

Communication Algorithms for Wireless Ad Hoc Networks

Viqar, Saira 2012 August 1900 (has links)
In this dissertation we present deterministic algorithms for reliable and efficient communication in ad hoc networks. In the first part of this dissertation we give a specification for a reliable neighbor discovery layer for mobile ad hoc networks. We present two different algorithms that implement this layer with varying progress guarantees. In the second part of this dissertation we give an algorithm which allows nodes in a mobile wireless ad hoc network to communicate reliably and at the same time maintain local neighborhood information. In the last part of this dissertation we look at the distributed trigger counting problem in the wireless ad hoc network setting. We present a deterministic algorithm for this problem which is communication efficient in terms of the the maximum number of messages received by any processor in the system.
5

Amélioration des adresses CGA et du protocole SEND pour un meilleur support de la mobilité et de nouveaux services de sécurité / Improving CGA addresses and the SEND protocol for a better mobility support and new security services

Cheneau, Tony 07 January 2011 (has links)
A l'origine conçus pour protéger le protocole de Découverte de Voisins (Neighbor Discovery Protocol, NDP) en IPv6, les adresses générées de manière cryptographique (Cryptographically Generated Addresses, CGA) et le protocole SEND (Secure Neighbor Discovery) doivent maintenant s'adapter au contexte de mobilité et à ses nouvelles fonctionnalités. Cette mobilité revêt de nombreuses formes : mobilité du noeud (Mobile IPv6, MIPv6), mobilité des routeurs (Network Mobility, NEMO) ou encore mobilité gérée par le réseau (Proxy Mobile IPv6). De nombreux changements doivent être opérés dans le protocole SEND : les opérations cryptographiques doivent être allégées pour les terminaux à faible capacité de calcul, les incompatibilités entre le partage d'adresse dans les protocoles de mobilité et le mécanisme de protection d'adresses de SEND doivent être corrigés, etc. Dans une première partie de cette thèse, nous présentons le protocole de Découverte de Voisins, les adresses CGA et le protocole de sécurité SEND. Nous étudions leurs limitations et, afin d'améliorer les performances, nous proposons l'utilisation de la cryptographie basée sur les courbes elliptiques (ECC). À travers une série de tests, nous mesurons l'impact de notre proposition. Par la suite, nous modifions les spécifications du protocole SEND afin de supporter de nouveaux algorithmes crytpographiques. Dans une deuxième partie, nous résolvons les incompatibilités entre le protocole SEND et les protocoles de mobilité (par ex. MIPv6) et entre le protocole SEND et les adresses anycast. Dans une dernière partie, nous présentons plusieurs contributions basées sur une utilisation dérivée des adresses CGA et du protocole SEND. / Originally designed to protect the Neighbor Discovery Protocol (NDP) (part of the IPv6 protocol suite), the Cryptographically Generated Addresses (CGA) and the Secure Neighbor Discovery (SEND) now need to be adapted to the context of Mobility and extended to new functionalities. The term "Mobility" encompasses many aspects, among them : node mobility (Mobile IPv6, MIPv6), router mobility (Network Mobility, NEMO) and network-based mobility management (Proxy Mobile IPv6, PMIPv6). Numerous changes need to be operated on the SEND protocol in order to comply with the Mobility : the cryptographic operations need to be adapted to operate on low power mobile nodes, the incompatibilities between the address sharing model of the mobile protocol and the address protections offered by SEND need to be fixed, etc. Firstly, we present the Neighbor Discovery protocol, the CGA addresses and the SEND protocol. We study their limitations, and, in order to improve their performances, we propose to replace the signature algorithm used in SEND (RSA) by the elliptic curves cryptography (ECC). We then evaluate the performances of our proposal. Subsequently, we modify the SEND protocol to include a signature algorithm selection mechanism. Secondly, we solve incompatilities between the SEND protocol and the mobility protocols (e.g. MIPv6) and between the SEND protocol and the anycast addresses. Finally, we present our contributions containing a derivate use of the CGA addresses and the SEND protocol.
6

Mobility and Multi-channel Communications in Low-power Wireless Networks

Gonga, António January 2015 (has links)
The prospect of replacing existing fixed networks with cheap, flexible and evenmobile low-power wireless network has been a strong research driver in recent years.However, many challenges still exist: reliability is hampered by unstable and burstycommunication links; the wireless medium is getting congested by an increasingnumber of wireless devices; and life-times are limited due to difficulties in developingefficient duty-cycling mechanisms. These challenges inhibit the industry to fullyembrace and exploit the capabilities and business opportunities that low-powerwireless devices offer. In this thesis, we propose, design, implement, and evaluateprotocols and systems to increase flexibility and improve efficiency of low-powerwireless communications. First, we present MobiSense, a system architecture for energy-efficient communicationsin micro-mobility sensing scenarios. MobiSense is a hybrid architecturecombining a fixed infrastructure network and mobile sensor nodes. Simulations andexperimental results show that the system provides high throughput and reliabilitywith low-latency handoffs. Secondly, we investigate if and how multi-channel communication can mitigate theimpact of link dynamics on low-power wireless protocols. Our study is motivated bya curiosity to reconcile two opposing views: that link dynamics is best compensatedby either (i) adaptive routing, or (ii) multi-channel communication. We perform acomprehensive measurement campaign and evaluate performance both in the singlelink and over a multi-hop network. We study packet reception ratios, maximumburst losses, temporal correlation of losses and loss correlations across channels.The evaluation shows that multi-channel communication significantly reduces linkburstiness and packet losses. In multi-hop networks, multi-channel communicationsand adaptive routing achieves similar end-to-end reliability in dense topologies,while multi-channel communication outperforms adaptive routing in sparse networkswhere re-routing options are limited. Third, we address the problem of distributed information exchange in proximitybasednetworks. First, we consider randomized information exchange and assess thepotential of multi-channel epidemic discovery. We propose an epidemic neightbordiscoverymechanism that reduces discovery times considerably compared to singlechannelprotocols in large and dense networks. Then, the idea is extended todeterministic information exchange. We propose, design and evaluate an epidemicinformation dissemination mechanism with strong performance both in theory andpractice. Finally, we apply some of the concepts from epidemic discovery to the designof an asynchronous, sender-initiated multi-channel medium access protocol. Theprotocol combines a novel mechanism for rapid schedule learning that avoids perpacketchannel negotiations with the use of burst data transfer to provide efficientsupport of ’multiple contending unicast and parallel data flows. / De senaste åren har forskning inom trådlös kommunikation drivits av önskemåletom att kunna ersätta nuvarande trådbundna kommunikationslänkar med trådlösa lågenergialternativ.Dock kvarstår många utmaningar, såsom instabila och sporadiskalänkar, överbelastning på grund av en ökning i antal trådlösa enheter, hur maneffektivt kan växla duty-cycling mekanismen för att förlänga nätverkens livstid,med flera. Dessa utmaningar begränsar industrin från att ta till sig och utnyttjade fördelar som trådlösa lågenergialternativ kan medföra. I den här avhandlingenföreslår, designar, implementerar och utvärderar vi protokoll och system som kanförbättra de nuvarande trådlösa lågenergialternativen. Först presenterar vi MobiSense, en systemarkitektur för energibesparande kommunikationi mikro-mobila sensorscenarier. MobiSense är en hybridarkitektur somkombinerar ett fast infrastrukturnätverk med rörliga sensornoder. Simulerings- ochexperimentella resultat visar att systemet uppnår en högre överföringskapacitet ochtillförlitlighet samtidigt som överlämnandet mellan basstationer har låg latens. I den andra delen behandlar vi hur effekterna från länkdynamiken hos protokollför lågenergikommunikation kan minskas, och försöker förena idéerna hos två motståendesynsätt: (i) flerkanalskommunikation och (ii) adaptiv routing. Vi analyserarenkanals- och flerkanalskommunikation över en-stegslänkar i termer av andelenmottagna paket kontra andelen förlorade, den maximala sporadiska förlusten avpaket, tidskorrelation för förluster och förlustkorrelation mellan olika kanaler. Resultatenindikerar att flerkanalskommunikation med kanalhoppning kraftigt minskardet sporadiska uppträdandet hos länkarna och korrelationen mellan paketförluster.För flerstegsnätverk uppvisar flerkanalskommunikation och adaptiv routingliknande tillförlitlighet i täta topologier, medan flerkanalskommunikation har bättreprestanda än adaptiv routing i glesa nätverk med sporadiska länkar. I den tredje delen studeras distribuerat informationsutbyte i närhetsbaseradenätverk. Först betraktas det slumpmässiga fallet och vi fastställer potentialen hosflerkanalig indirekt utforskning av nätverket. Vi analyserar ett trestegs protokoll,som möjliggör en snabbare utforskning av nätverket. Sedan föreslår vi en ny algoritmför att upptäcka grannarna i ett flerkanalsnätverk, som kraftigt minskarutforskningstiden i jämförelse med ett enkanalsprotokoll. Vi utökar även problemettill det deterministiska fallet och föreslår en mekanism för informationsspridningsom påskyndar utforskningstiderna för deterministiska protokoll. Utvidgningen hartvå huvudförbättringar som leder till kraftigt ökad prestanda samtidigt som degaranterar att utforskningsprocessen är deterministisk. Till sist applicerar vi koncepten rörande indirekt utforskning för att designa,implementera och evaluera ett asynkront sändare-initierat flerkanals MAC protokollför trådlös lågenergikommunikation. Protokollet kombinerar en ny mekanism försnabbt lärande av tidsschemat, vilket undviker kanalförhandling för varje paket,med sporadisk dataöverföring. Detta möjliggör ett effektivt tillhandahållande avflera konkurrerande och parallella dataflöden. / <p>QC 20151204</p>
7

Efficient Location Verification, Neighbor Discovery and Routing in Ad Hoc Wireless Networks

Vora, Adnan Zoeb 07 October 2009 (has links)
No description available.
8

Techniques de conservation de l'énergie dans les réseaux de capteurs mobiles : découverte de voisinage et routage / Techniques of energy conservation in mobile sensor networks : neighbor discovery and routing

Sghaier, Nouha 22 November 2013 (has links)
Le challenge de la consommation d'énergie dans les réseaux de capteurs sans fil constitue un verrou technologique qui reste un problème ouvert encore aujourd'hui. Ces travaux de thèse s'inscrivent dans la problématique de la conservation de l'énergie dans les réseaux de capteurs et s'articulent autour de deux axes. Dans la première partie, nous abordons le dimensionnement des protocoles de découverte de voisinage. Nous proposons deux techniques de dimensionnement de ces protocoles qui visent à optimiser la consommation d'énergie des nœuds capteurs. La première technique, PPM-BM, consiste à dimensionner le protocole de découverte de voisins en fonction du niveau de batterie du nœud. La deuxième approche, ECoND, vise à ajuster la fréquence de découverte de voisins en fonction de la connectivité estimée à chaque instant. Cette technique tire profit des cycles temporels des modèles de mouvement des nœuds. La connectivité est estimée en se basant sur l'historique des rencontres. La découverte de voisins est ajustée en fonction du taux de connectivité estimé. Les résultats enregistrés mettent en évidence l'efficacité de ces deux techniques dans l'optimisation de la consommation d'énergie des nœuds sans affecter les performances de taux de livraison de messages et d'overhead. La deuxième partie de la thèse concerne l'optimisation des performances des réseaux de capteurs en termes de durée de vie. Nous reconsidérons dans cette partie certains protocoles de routage relevant du domaine des réseaux à connectivité intermittente et nous proposons le protocole EXLIOSE qui se base sur la capacité d'énergie résiduelle au niveau des nœuds pour assurer un équilibre énergétique, partager la charge et étendre à la fois la durée de vie des nœuds ainsi que celle du réseau / The challenge of energy consumption in wireless sensor networks is a key issue that remains an open problem. This thesis relates to the problem of energy conservation in sensor networks and is divided into two parts. In the first part, we discuss the design of neighbor discovery protocols. We propose two techniques for modulating these protocols in order to optimize the energy consumption of sensor nodes. The first technique, PPM-BM aims to modulate the neighbor discovery protocol based on the battery level of the node. The second approach ECoND aims to set up the frequency of neighbor discovery based on estimated connectivity. This technique takes advantage of the temporal cycles of nodes' movement patterns. Connectivity is estimated based on encounters' history. A neighbor discovery is set up based on the estimated rate of connectivity. The achieved results demonstrate the effectiveness of these techniques in optimizing the energy consumption of nodes while maintaining acceptable message delivery and overhead rates. In the second part of the thesis, we contribute to the optimization of the performance of sensor networks in terms of network lifetime. We review in this section some routing protocols for networks with intermittent connectivity and we propose EXLIOSE protocol which is based on residual energy to ensure energy-balancing, load sharing and network lifetime extending
9

MEMS-based Free Space Optical Networks

Atakora, Michael O. 23 May 2022 (has links)
No description available.
10

Analýza a demonstrace vybraných IPv6 útoků / An Analysis of Selected IPv6 Network Attacks

Pivarník, Jozef January 2013 (has links)
This master's thesis analyses and demonstrates selected IPv6 attacks including two Man-in-the-Middle attacks and one Denial of Service attack - Rogue Router Advertisement, Neighbor Cache Poisoning and Duplicate Address Detection DoS, respectively. In the first part the author presents necessary information related to the issue and provides detailed information on how to realize these attacks in practice using publicly available tools. The second part of the thesis presents various ways of mitigating presented attacks, analyses implementations of some of those countermeasures on Cisco and H3C devices and discussess their applicability.

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