Mobilūs Ad-Hoc tinklai yra labai naudingi įvairiose situacijose, tačiau jų realizacijose vis dar neišspręsta daug problemų ir viena iš didžiausių problemų yra saugumas. Maršrutizavimui reikalingi specialiai suprojektuoti maršruto protokolai ir jie yra gana gerai išvystyti, išskyrus saugumo sritį. Darbe aš labiausiai telkiau dėmesį į įvairias aktyvias atakas prieš ad hoc tinklą, vykdomas iškreipiant maršruto parinkimo procesą ir kompromituojant tinklo paslaugų prieinamumą, duomenų vientisumą ir konfidencialumą, o labiausiai į saugaus maršruto parinkimo protokolų, kurie gali būti naudojami siekiant išvengti šių pavojų, analizę. Naujos koncepcijos saugaus maršruto parinkimo protokolas siūlomas, kaip konkretaus atvejo - iš tiesų didelio kenkiančių mazgų kiekio tinkle sprendimas ir sukurtas nesaugaus ad hoc tinklo modelis, kuris naudojamas siekiant imituoti, gauti ir palyginti keleto saugaus maršruto parinkimo protokolų rodiklius. / Mobile Ad-Hoc networks are very useful in certain situations, but raise many challenges and one of the biggest is security. Specially designed routing protocols are required and they are quite well developed except for security area. In this thesis I concentrate on various active attacks on ad-hoc network during routing process, compromising network availability, data integrity and confidentiality and analyze some security aware protocols, that can be used to avoid these risks. New concept routing protocol is proposed, for coping with a specific scenario of really high level of malicious nodes on the network and insecure network model is created, which is used to simulate, get and compare performance metrics of some security aware routing protocols.

BBR is a congestion control recently proposed by Google, unlike the traditional congestion control which uses packet loss as the signal of congestion, BBR uses the estimation of bottleneck bandwidth to control the sending rate. However, recent work shows that BBR suffers from a variety of problems such as large queuing delays with multiple flows in the network. Most of the existing work in this area has so far focused on the performance analysis of BBR. Despite these efforts, there exists still a lack of understanding on how to improve the performance of BBR in different scenarios. In this paper, we first present the behaviour of the original BBR in the Network Simulator 3 (ns-3), then, we provide an improvement that carefully adjusts the pacing rate based on the RTT of the flow, finally, to validate our method, we run simulations varying different bottlenecks, latency, and numbers of flows in both small and large buffer size scenarios on ns-3 network simulator. The results show that our improvement can significantly reduce the queuing delay on the bottleneck at a very small cost of throughput in large buffer scenarios, and also achieve less than 0.1% retransmission rate in small buffer scenarios. / BBR är en typ av stockningskontroll som nyligen föreslagits av Google. Till skillnad från traditionell stockningskontroll som använder paketförlust som stockningssignal använder BBR en uppskattning av bandbredden i flaskhalsen mellan sändare och mottagare för att styra sändningshastigheten. Senare arbete visar dock att BBR lider av olika problem, såsom långa förseningar i paketköer med flera flöden i nätverket. Det mesta av det befintliga arbetet inom detta område har hittills fokuserat på att analysera BBR-prestanda. Trots dessa ansträngningar saknas det fortfarande förståelse för hur man kan förbättra BBR:s prestanda i olika scenarier. I den här rapporten presenterar vi först beteendet hos den ursprungliga BBR i nätverkssimulatorn ns-3. Därefter föreslår vi en förbättring som noggrant justerar sändningstakten enligt RTT (Round Trip Time) för flödet. Slutligen, för att validera vår metod, utför vi simuleringar som varierar olika flaskhalsar, fördröjningar och antal paketströmmar i små och stora buffertstorlekar i ns-3. Resultaten visar att vår förbättring avsevärt kan minska köfördröjningar i flaskhalsar för stora buffertstorlekar till en mycket låg kostnad i genomströmning, samt uppnå mindre än 0.1% omsändningshastighet i scenarier med små buffertstorlekar.

Tato práce zkoumá vhodnost a požadavky návrhu simulací pro simulátor NS-3 pro případ bezdrátových sítí používaných v měřící infrastruktuře společnosti Kamstrup. V práci je popsán simulátor NS-3 a je vytvořena základní implementace dvou protokolů. Wireless M-Bus jako příklad jednosměrného protokolu pro zařízení napájené z baterií. Simulace Wireless M-Bus je porovnána s daty naměřenými v reálném systému. NS-3 poskytuje flexibilní prostředí pro vývoj simulací různých síťových protokolů, včetně těch určených pro sítě inteligentních měřidel.

IP networks have become an increasingly protable option over traditional communication networks. Despite the advantages of VoIP compared to PSTN, it is not possible to replace one technology by the other instantly, due to the complexity involved. This implies a transition period in which the two technologies will coexist. In order to make this feasible, there must be a system for mapping E.164 numbers (used in the PSTN) to URIs (used in the IP network). In this context, the ENUM protocol is gaining prominence as the most promising solution. However, it is not very spread yet. In addition, there are technical issues and especially political and economic interests that need to be worked so that this protocol can be popularized. Regarding technical issues, there is a shortage of tools for the study of this protocol. Thus, this dissertation proposes a simulation platform that enables the study of the ENUM protocol. The project design of the simulator was based on experiments carried out in the laboratory, the proposition of mathematical models and, subsequently, implementation, integration and validation of the simulator. The results indicate that the simulation platform rightly describes the real system considered. The results also proved the success of the proposed modeling strategy. In addition, new modules were developed for the NS-3 simulation environment, oering new opportunities for researchers. / As redes IP têm se tornado uma opção cada vez mais vantajosa em relação às redes de comunicações tradicionais. Mesmo diante das vantagens oferecidas pela tecnologia VoIP em relação à PSTN, não é possível uma substituição instantânea de uma tecnologia pela outra devido à complexidade envolvida. Isto implica em um período de transição em que as duas tecnologias irão conviver. Para que isto seja realizável, é necessário que exista um sistema de mapeamento entre números E.164 (utilizados na PSTN) e URIs (utilizados na rede IP). É neste contexto que o protocolo ENUM vem ganhando destaque como a solução mais promissora. Entretanto, a sua disseminação ainda é baixa. Além disso, existem questões técnicas e, principalmente, interesses políticos e econômicos que precisam ser trabalhados para que este protocolo seja popularizado. Em relação às questões técnicas, existe uma escassez de ferramentas para o estudo deste protocolo. Neste sentido, esta dissertação apresenta uma proposta de plataforma de simulação que possibilite o estudo do protocolo ENUM. Dessa maneira, o projeto de concepção do simulador foi baseado na realização de testes em laboratório, na proposição de modelos matemáticos e, posteriormente, na implementação, integração e validação do simulador. Os resultados indicam que a plataforma de simulação descreve com delidade o sistema real considerado. Os resultados também comprovaram o sucesso da estratégia de modelagem proposta. Além disso, novos módulos foram desenvolvidos para o ambiente de simulação NS-3, oferecendo novas possibilidades para os pesquisadores da área. / Mestre em Ciências

Personal Rapid Transit systems have high demands on its reliability and security. Many of the fundamental functions needed by a PRT system can be provided by a wireless radio communication link. The goal of this thesis is to determine if the emerging radio standard for intelligent transportation systems is suitable for providing some of the needed functions. The emphasis of this work is to understand the features of the standard that are important for a PRT system and to verify them with simulation.

Small mobile devices with networking capabilities are becoming more and more readily available and used. These devices can be used to form mobile ad hoc networks to communicate, where no infrastructure for network communication exist or where it has been destroyed or is overloaded e.g. in a natural disaster such as a hurricane. Such networks are almost never fully connected, and are part of the category of delay/disruption-tolerant networks (DTN) and suffer from limited resources e.g. bandwidth, storage and limited energy supply. The Opportunistic DTN Routing With Window-aware Adaptive Replication (ORWAR) is a delaytolerant protocol intended to be used in disaster relief efforts or emergency operations were a DTN could be a fast way to establish communication. In these kinds of scenarios high success rate together with efficient usage of the networks resources are critical to the success of such operations. ORWAR has been implemented and simulated on a high-level simulator, with promising results. To make a better assessment about what ORWARs performance would be in a real world network, more realistic and detailed simulations are needed. This Master's Thesis describes the design, implementation and evaluation of ORWAR in the network simulator ns-3, which simulates networks down to physical layer. The contributions of this thesis is a extension to ns-3 giving it an framework with support for the bundle protocol and delay-tolerant routing protocols and an evaluation of the ORWAR performance using more detailed simulations. The simulations represent a city scenario in down-town Helsinki city, Finland, were pedestrians, cars and trams form a network to communicate. The simulations with a higher level of detail has added to insight about the protocol. The obtained results showed that the high-level simulation may be overly optimistic and hides implementation details. On the other hand, some assumptions were found to be too pessimistic. For example we have shown that ORWAR actually performs better than the high level simulations, with regard to partial transmissions and that the high-level simulations have rather optimistic assumptions regarding the latency.

This thesis is dealing with the problem of MTC (Machine Type Communication) devices accessing LTE (Long Term Evolution) network. First part of work contains theoretical description of MTC, LTE network and possibility of using QoS (Quality of Service) for this type of communication. Influence of simultaneous access of large number of MTC devices into LTE network is examined. A solution is proposed -- usage of MTCG. In simulation enviroment NS-3 (Network Simulator 3), two scenarios are created for simulation with and without MTCG. The results of these simulations are then compared.

Although smart meters are deployed in many countries, the data collection process from smart meters in Smart Grid (SG) still has some challenges related to consumer privacy that needs to be addressed. Referred to as Advanced Metering Infrastructure (AMI), the data collected and transmitted through the AMI can leak sensitive information about the consumers if it is sent as a plaintext. While many solutions have been proposed in the past, the deployment of these solutions in real-life was not possible since the actual AMIs were not accessible to researchers. Therefore, a lot of solutions relied on simulations which may not be able to capture the real performance of these solutions. In this thesis, two 802.11s wireless mesh-based SG AMI network testbeds are developed with Beaglebone Black and Raspberry Pi 3 boards to provide a baseline for the simulations. The Raspberry Pi 3 testbed is also configured to be remotely accessible.

This thesis deals with analysis and modelling of power line communications. The main aim is to examine the effects influencing transsmision of communication signals on powerline networks and theoretical capacity of the PLC channel using PLC framework created in NS-3. The introduction summarizes the theoretical knowledge in the area of data transmission over power line distribution network. Different types of noise and possibilities of calculation of theoretical transmission capacity are described as well. Several simple simulations are realized in practical part of this paper. These simulations explore the influence of the distance between the transmitter and receiver, length, impedance and number of branches between these nodes, affect of the type of modulation and noise on the transfer function as well as the capacity of the channel. There are also some simulations for large topology based on real position of electrometer. The main focus is to find positions of repeaters to ensure that some nodes of the topology can communicate.

This diploma thesis is analysis of routing protocols used in MANET networks focusing on protocols OLSR, AODV and HWMP. The work consists of a theoretical and practical part. The theoretical part describes the routing protokols, which are used in MANET networks and their applications to FANET networks. In practical part, there are describes of created mobility model in the NS-3, which are used for comparison routing protocols on the created scenarios of mobility according to the qualitative parameters of the networks.