Avsikten med detta arbete har varit att undersöka huruvida någon prestandaskillnad föreligger mellan nätverksnodernas vidarebefordring av prioriterad trafik i en nätverksmiljö med Quality of service-funktioner (QoS) implementerade och nätverksnodernas arbete i samma nätverksmiljö med separata, virtuella nätverk uppsatta med hjälp av Virtual routing and forwarding (VRF). Målet var att resultatet ska ha möjlighet att väga in när för- och nackdelar mellan olika sätt att separera nätverkstrafik jämförs ur prestandasynpunkt. Rapporten beskriver arbetet med samt resultatet av ett empiriskt experiment som kontrollerade VRF:ers påverkan på QoS-funktioner. Ett fysiskt nätverk sattes upp för att kontrollera hur QoS påverkades av logisk separering av experimentmiljöns nätverk på lager tre med hjälp av VRF. I detta nätverk utfördes även ett kontrollexperiment utan logisk separation för att skapa en baseline samt ett experiment där separering utfördes med hjälp av accesslistor. För varje experimentfas skickades en videoström genom experimentmiljön för att mäta End to end delay, Packet loss och Jitter, samt webbside requests för att upp mäta Round trip time. Detta testförfarande utfördes tre gånger per experimentfas.   I experimenten kunde ingen Packet loss uppmätas vilket tyder på att QoS fungerade som avsett, även med VRF. Vissa förändringar för nätverksnoderna behövde genomföras beroende på teknik, vilket gjorde att det blev svårt att dra en slutsats av resultaten för End to end delay, Jitter och Round trip time.

In the Internet of today there is a demand for both high bandwidth and low delays. Bandwidth-heavy applications such as large downloads or video streaming compete with more delay-sensitive applications; web-browsing, VoIP and video games. These applications represent a growing share of Internet traffic. Buffers are an essential part of network equipment. They prevent packet loss and help maintain hight throughput. As bandwidths have increased so have the buffer sizes. In some cases way to much. This, and the fact that Active Queue Management (AQM) is seldom implemented, has given rise to a phenomenon called Bufferbloat. Bufferbloat is manifested at the bottleneck of the network path by large flows creating standing queues that choke out smaller, and usually delay-sensitive, flows. Since the bottleneck is often located at the consumer edge, this is where the focus of this thesis lies. This work evaluates three different AQM solutions that lower delays without requiring complicated configuration; CoDel, FQ_CoDel and PIE. FQ_CoDel had the best performance in the tests, with the lowest consistent delays and high throughput. This thesis recommends that AQM is implemented at the network edge, preferably FQ_CoDel.

The demand of wireless spectrum is increasing very fast as the field of telecommunication is advancing rapidly. The spectrum was underutilized because of fixed spectrum assignment policy and this valuable spectrum can be utilized efficiently by cognitive radio technology. In this thesis we have studied spectrum selection problems in cognitive radio network. Channel sharing and channel contention problems arise when multiple secondary users tend to select same channel. The thesis work is focused on spectrum selection issue with the aim to minimize the overall system time and to solve the problem of channel contention and channel sharing. The overall system time of secondary connection is an important performance measure to provide quality of service for secondary users in cognitive radio network. We studied two spectrum selection schemes that considerably reduce the overall system time and resolve the problems of channel sharing and channel contention. An analytical model associated with Preemptive Resume Priority (PRP) M/G/1 queuing model has been provided to evaluate the studied spectrum selection scheme. This model also analyzes the effect of multiple handoffs due to arrival of primary users. According to this scheme, the traffic load is distributed among multiple channels to balance the traffic load. Secondary users select the operating channels based on the spectrum selection algorithm. They can intelligently adopt better channel selection scheme by considering traffic statistics and overall transmission time. All simulation scenarios are developed in MATLAB. Based on our result we can conclude that both channel selection schemes considerably reduce the overall transmission time of secondary users in cognitive radio network. The overall transmission time increase with the rise of arrival rate of secondary user. The probability based channel selection scheme perform better with lower arrival rate and sensing based channel selection scheme perform better with higher arrival rate of secondary users. These channel selection schemes help distribute the traffic load of secondary users evenly among multiple channels. Hence, increase the channel utilization and resolve the channel contention problem.

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.

Abstract The current Internet infrastructure must be architected to handle future media-rich, and content rich applications. The success of applications such as video-on-demand, multicast and content distribution depends on Quality of Service and bandwidth guarantees. Over the years, the Internet has encompassed many changes in traffic profiles and applications, in bandwidths and utilization, but the future Internet infrastructure necessitates a very different architecture supporting Quality of Service (QoS). A satellite, distinguished by features such as global coverage, bandwidth flexibility, broadcast, multicast, and reliability, is an excellent candidate to provide broadband integrated Internet access. The aim of this thesis is to explore suitability of satellite technologies for broadband Internet services with significant emphasis on the question of defining, assessing, and developing QoS models for satellite ATM and IP broadband networks with and without onboard processing. For the satellite Internet, Transmission Control Protocol (TCP) performance is degraded due to long propagation delays, link errors, and bandwidth asymmetry. In this thesis, for satellite ATM, fundamental questions such as buffer requirements, TCP/ATM efficiency, fairness, and multiple access are addressed through extensive simulations in a quantitative way. Buffer designs for TCP over satellite ATM Unspecified Bit Rate (UBR) service are performed. A buffer size equal to half the round trip delay-bandwidth product of the TCP connections provides high efficiency for TCP over satellite UBR. An extensive TCP analysis via simulation study for various TCP mechanisms and end system policies show that for satellite environment end system policies are more important than switch drop policies in terms of efficiency and fairness for World Wide Web traffic. A bandwidth allocation scheme is proposed and analytical model for supporting voice and video service over a broadband satellite network is developed. The study results demonstrate that non-contiguous allocation can afford higher gain in uplink utilizations. In this thesis, for the first time, Integrated Services and Differentiated Services based QoS architectures for broadband satellite IP networks are proposed and analyzed. In multimedia applications where User Datagram Protocol (UDP) is used along with TCP, a fair excess bandwidth allocation is not possible because TCP is congestion sensitive whereas UDP is congestion insensitive. An extensive simulation model is developed to study the effect of precedence levels for reserved rate utilization and fairness with different buffer management policies. The simulation results indicate that three levels of precedence are required for better utilization. Multiprotocol Label Switching (MPLS) over Satellite network has been proposed and a simulation model developed to study the throughput performance impacts for TCP and UDP. The traffic engineering of MPLS facilitates efficient and reliable network design to optimize the utilization of network resources and enhance the network QoS. A novel Code Division Multiple Access based Spread ALOHA single code multiple access scheme for broadband satellite return channel is proposed as an alternative to Multifrequency-Time Division Multiple Access based Digital Video Broadcasting-Return Channel via Satellite protocol. It is shown through Monte Carlo simulations that throughput for Spread ALOHA One Long Code equivalent to packet length, is better than Spread ALOHA One Code in which spreading sequence repeats every symbol. The reduction of throughput due to multi-user interference for different number of users is shown. Further research on QoS architectures, performance models for TCP enhancements, interworking functions, interoperability, and standardization efforts is included.

Video streaming through IP networks has risen rapidly over the recent years, and will continue to do so over the coming years. In addition to this, new technologies such as Virtual Reality and robotics will lead to many new applications that will put high pressure on the networks. To combat these challenges, networks need to be application sensitive, and be able to provide Quality of Service (QoS) based on requirement. Network paradigms like Software Defined Networking (SDN) enables the network to be directly programmable, and could thus solve the challenge. In this thesis, the objective is to research if SDN can provide High QoS. Methods are developed to achieve High QoS with SDN. A combination of Differentiated Services Code Point (DSCP) values and DSCP remarking with Meters are used enable High QoS and together they can give bandwidth guarantee. As a result of the thesis, a solid theoretical method is provided for achieving QoS, tests are performed and show that QoS can be implemented in SDN, but it is unable to implement High QoS due to the lack of implementation for Meters with DSCP remarking.

As the vision of the Internet of Things (IoT) becomes a reality, thousands of devices will beconnected to IoT platforms in smart cities and regions. These devices will actively send dataupdates to cloud-based platforms, as part of smart applications in domains like healthcare, trafficand pollution monitoring. Therefore, it is important to study the ability of modern IoT systemsto handle high rates of data updates coming from devices. In this work we evaluated the per-formance of components of the Internet of Things Services Enablement Architecture of theEuropean initiative FIWARE. We developed a testbed that is able to inject data updates usingMQTT and the CoAP-based Lightweight M2M protocols, simulating large scale IoT deploy-ments. Our extensive tests considered the vertical and horizontal scalability of the componentsof the platform. Our results found the limits of the components when handling the load, and thescaling strategies that should be targeted by implementers. We found that vertical scaling is notan effective strategy in comparison to the gains achieved by horizontally scaling the databaselayer. We reflect about the load testing methodology for IoT systems, the scalability needs ofdifferent layers and conclude with future challenges in this topic.

Les réseaux de capteurs sans fil (RCSFs) ont suscité un grand intérêt scientifique durant cette dernière décennie. Un des grands défis des RCSFs est d'assurer une communication avec la Qualité de Service (QoS) exigée par l'application tout en prenant en considération les contraintes intrinsèques des capteurs. Un autre défi est relatif à la génération des trafics hétérogènes avec des priorités diverses, ce qui impose des contraintes supplémentaires aux différents protocoles de communication. Dans cette thèse, nous nous intéressons aux protocoles de routage dédiés aux RCSFs. Dans un premier temps, nous proposons des améliorations de deux protocoles appartenant à deux catégories différentes de routage. L'objectif est de surmonter les contraintes liées aux caractéristiques des capteurs sans fil et d'assurer de meilleure performance. Dans un deuxième temps, nous proposons une solution pour remédier à la vulnérabilité de la technique des chemins multiples aussi bien dans le cas d'une seule source ou que dans le cas de plusieurs sources. Ainsi, nous avons proposé un protocole de routage à chemins multiples, capable de créer des chemins tout en évitant l'effet du rayon de détection de porteuse. Ce protocole nommé « Carrier Sense Aware Multipath Geographic Routing (CSA-MGR) », satisfait la QoS exigée par les RCSFs. Comme application directe de notre solution, nous avons étudié un scénario d'irrigation par goutte-à-goutte en utilisant les RCSFs. Principalement, nous nous sommes intéressés au cas d'un dysfonctionnement de système, tel que la rupture des tuyaux d'irrigation ou bien le blocage des émetteurs. Ainsi, nous distinguons deux niveaux de priorité pour les informations transmises par le réseau, et en utilisant le protocole CSA-MGR, nous concevons un routage selon la priorité exigée. Notre travail a été validé avec NS2 et TOSSIM ainsi par une implémentation réelle sur des noeuds capteurs TelosB. Les résultats des simulations numériques et des tests expérimentaux montrent l'apport de nos contributions par rapport aux solutions existantes. / Wireless Sensor Networks (WSNs) have aroused great scientific interest during the last decade. One of the greatest challenge of WSNs is to ensure communication with the Quality of Service (QoS) required by the application while taking into account the inherent constraints of the sensor nodes. Another challenge is related to the generation of heterogeneous traffic with different priorities, which imposes additional constraints on different communication protocols. In this thesis, we are interested specifically to routing protocols dedicated to WSNs. First, we propose improvements of protocols based on combinatorial optimization techniques and those based on nodes geographic positions to overcome the related constraints of WSNs. Secondly, we propose a solution to address the vulnerability of the multiple paths technique, whether for the case of a single source or several sources in the network. Thus, our main contribution is to provide a multi-path routing protocol, able to creating paths while avoiding the carrier sense range effect. This protocol denoted "Carrier Sense Aware Multipath Geographic Routing (CSA-MGR)" meets the QoS required by WSNs. As direct application of our solution, we studied a drip irrigation scenario using WSNs. Mainly, we studied the case where a system dysfunctioning occurs, such as irrigation pipe rupture or the emitters blocking. Also, we distinguish two priority levels for the data transmitted over the network, and based on the CSA-MGR, we design routing according to the required priority. Our work in this thesis has been validated through NS2 and TOSSIM simulators and also through a real implementation over the TelosB motes. The results of numerical simulations and experimental results show the advantage of our contributions compared to existing solutions.

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Intelligent Transportation Systems (ITS) are gaining momentum among researchers. ITS encompasses several technologies, including wireless communications, sensor networks, data and voice communication, real-time driving assistant systems, etc. These states of the art technologies are expected to pave the way for a plethora of vehicular network applications. In fact, recently we have witnessed a growing interest in Vehicular Networks from both the research community and industry. Several potential applications of Vehicular Networks are envisioned such as road safety and security, traffic monitoring and driving comfort, just to mention a few. It is critical that the existence of convenience or driving comfort services do not negatively affect the performance of safety services. In essence, the dissemination of safety services or the discovery of convenience applications requires the communication among service providers and service requesters through constrained bandwidth resources. Therefore, service discovery techniques for vehicular networks must efficiently use the available common resources. In this thesis, we focus on the design of bandwidth-efficient and scalable service discovery protocols for Vehicular Networks. Three types of service discovery architectures are introduced: infrastructure-less, infrastructure-based, and hybrid architectures. Our proposed algorithms are network layer based where service discovery messages are integrated into the routing messages for a lightweight discovery. Moreover, our protocols use the channel diversity for efficient service discovery. We describe our algorithms and discuss their implementation. Finally, we present the main results of the extensive set of simulation experiments that have been used in order to evaluate their performance.