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Makarem, Nabil. "Performance evaluation and improvement of congestion control of the constrained application protocol for the Internet-of-things". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS289.
Pełny tekst źródłaThe Constrained Application Protocol (CoAP) is a lightweight core protocol designed by the Internet Engineering Task Force (IETF) used for communication between devices in the Internet of Things (IoT). In this research work, we propose new exact mathematical models to analyze the performance of CoAP in lossy IoT networks. This study provides insights about improving CoAP congestion control in such networks and highlights the properties -- including the limitations -- of CoAP. Besides, we show that the simple control mechanism reduces significantly CoAP performance especially in terms of bandwidth utilization since it prevents the protocol from acting efficiently during congestion periods. We then propose new improvements in order to enhance the trade-off between reliability and goodput while keeping the algorithms reasonably simple for constrained devices. First, we optimize further the estimation procedure of the retransmission timeout in order to enhance congestion detection. Timeouts are the only indicator used in CoAP to detect losses, and losses are used as a strong indicator to detect congestion. Second, we replace the backoff algorithm by "real" congestion control algorithms inspired from the well-known Additive Increase Multiplicative Decrease technique and a recent measurement-based congestion control called BBR. Our analysis using both our simulator and Contiki/Cooja environment show that the rate-based approach outperforms the backoff-based approach. Moreover, all the results show that our algorithms achieve a much better tradeoff between goodput, reliability and overhead
Stanica, Razvan. "Contrôle de Congestion dans les Réseaux Véhiculaires". Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0130/document.
Pełny tekst źródłaThe equipment of vehicles with wireless communication devices in order to improve road safety is a major component of a future intelligent transportation system. The success and availability of IEEE 802.11-based products make this technology the main competitor for the Medium Access Control (MAC) layer used in vehicle-to-vehicle communication. The IEEE 802.11p amendment has been specially designed in this special context of wireless access in vehicular environments. However, as all the other approaches based on Carrier Sense Multiple Access (CSMA), this protocol presents scalability problems, which leads to poor performance in high density scenarios, quite frequent in the case of a vehicular ad hoc network (VANET). This thesis studies the congestion control problem in the context of safety vehicular communications, with a special focus on the back-off mechanism and the carrier sense function. First of all, a number of important characteristics presented by the safety messages are discovered and understood by the means of an analytical framework. Second, the lessons learned from the analytical study are put into practice with the design of two adaptive mechanisms (one for the contention window and the other one for the carrier sense threshold) that take into account the local vehicular density. These mechanisms remain simple, but highly efficient, while also being straightforward to integrate in IEEE 802.11 devices. Finally, by taking into account the most important properties of a safety VANET, a new CSMA-based MAC protocol is proposed. This new access method, named Safety Range CSMA (SR-CSMA), relies on the idea that collisions can not be avoided in a high density network. However, by increasing the number of simultaneous transmissions between geographically distant nodes, SR-CSMA manages to better protect the immediate neighborhood, the most important area for safety applications
Rozhnova, Natalya. "Congestion control for Content-Centric Networking". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066132/document.
Pełny tekst źródłaThe network resources are shared between a large number of users. It may potentially create a risk for buffer overflow and performance degradation. That is why congestion control is critical to guarantee network performance. Congestion control schemes have been widely studied in the past but only recently in the context of CCN (Content-Centric Networking).This thesis explores the congestion control risk of CCN, identifies the bottlenecks and proposes strategies to circumvent them. We have designed our original hop-by-hop Interest shaping mechanism (HoBHIS) that nicely exploits the flow balance enforced in CCN between Interest and Chunk packets. It monitors active conversations sharing the transmission buffer of a CCN node face in order to dynamically adjust their Interest sending rate and enforce the Chunk queue length to converge to a defined objective. This mechanism is implemented in each CCN node. Then, we extended HoBHIS in order to address several important concerns that might occur in CCN. We proposed a Tolerance mechanism that controls the Clients sending rate as well as prevents the loss of Interest packets. We demonstrated the efficiency of our mechanisms through mathematical proofs and simulations performed in ndnSIM.Our results have been published in international conferences. The work has generated interest from the networking community. Particularly, "Cisco Systems" invited us to join their project on developing Named-Data Networking (NDN) traffic control mechanism. As one of the important results of this collaboration is a research article that got a SIGCOMM ICN workshop’13 “Best paper award”. This paper is also presented as a part of the dissertation
Rozhnova, Natalya. "Congestion control for Content-Centric Networking". Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066132.
Pełny tekst źródłaThe network resources are shared between a large number of users. It may potentially create a risk for buffer overflow and performance degradation. That is why congestion control is critical to guarantee network performance. Congestion control schemes have been widely studied in the past but only recently in the context of CCN (Content-Centric Networking).This thesis explores the congestion control risk of CCN, identifies the bottlenecks and proposes strategies to circumvent them. We have designed our original hop-by-hop Interest shaping mechanism (HoBHIS) that nicely exploits the flow balance enforced in CCN between Interest and Chunk packets. It monitors active conversations sharing the transmission buffer of a CCN node face in order to dynamically adjust their Interest sending rate and enforce the Chunk queue length to converge to a defined objective. This mechanism is implemented in each CCN node. Then, we extended HoBHIS in order to address several important concerns that might occur in CCN. We proposed a Tolerance mechanism that controls the Clients sending rate as well as prevents the loss of Interest packets. We demonstrated the efficiency of our mechanisms through mathematical proofs and simulations performed in ndnSIM.Our results have been published in international conferences. The work has generated interest from the networking community. Particularly, "Cisco Systems" invited us to join their project on developing Named-Data Networking (NDN) traffic control mechanism. As one of the important results of this collaboration is a research article that got a SIGCOMM ICN workshop’13 “Best paper award”. This paper is also presented as a part of the dissertation
Barakat, Chadi. "Evaluation des performances du contrôle de congestion dans l'Internet". Nice, 2001. http://www.theses.fr/2001NICE5622.
Pełny tekst źródłaWe study in this thesis the performance of the congestion control mechanisms of the TCP protocol. These mechanisms are very important for the stability of the Internet given the huge amount of the TCP traffic. For the purpose of our study we develop some analytical models. Our models are divided into two main groups : the end-to-end models and the network-specific models. The objective of the end-to-end models is to come up with simple expressions of the throughput of a long-life TCP connection. We try to keep our models as general as possible so that they cover the different ways with which the network drops the packets of the TCP connection. Using techniques from the theory of stochastic processes, we find explicit expressions for TCP throughput that we validate via measurements over the Internet. Concerning the network-specific models, our objective is to study the performance of TCP in challenging environments. We focus on the three environments considered in the literature as the most challenging for TCP : the large bandwidth-delay product environment, the asymmetric-bandwidth environment, and the wireless environment. For each environment, we propose an analytical model as well as some mechanisms and guidelines to improve the performance of TCP transfers. The different results of our second group of models are validated via ns simulations. The thesis also contains a presentation of the different works on TCP congestion control mechanisms since their introduction into the internet
Legout, Arnaud. "Contrôle de congestion multipoint pour les réseaux best effort". Nice, 2000. http://www.theses.fr/2000NICE5451.
Pełny tekst źródłaLenoir, Nathalie. "Une approche economique de la congestion aerienne". Toulouse 1, 1995. http://www.theses.fr/1995TOU10012.
Pełny tekst źródłaOur work takes place in the context of a general body of work conducted on airline liberalization in europe. Some aspects of the liberalization policy, like the free acces to the market for all airlines, and the possibility of competition on short and medium haul flights are jeopardized by the limits on the infrastructure's capacities. The aeronautic infrastructure consists of the airports and the air trafic control system. In europe, they are both becoming rapidly congested, with no short term solution to the problem. Therefore, it is important to optimize the way the existing capactties are used. Since those capacities are managed in a monopolistic fashion, and are subjected to very high peak demands, in the first part we examine the economic theories relevant to regulation and peak load pricing. In the second part, we study the allocation of airport capacity. Although we mention the possibility of peak load pricing, we focus more specifically on the allocation through airport, which are the chosen solution in the usa and in europe. After reviewing the americain experience with slots, we concentrate on the europeen case and conclude by emphasizing the difficulty of restoring the social optimum. In the third part, we deal with the air trafic control, and review the caracteristics of supply and demand. An analysis of traffic in france shows that the role of small aviation is generally under-estimated. Also, a study of current taxes shows that they have a negative impact on congestion, resulting in delays, which we then estimate with econometric techniques. Finally, several economic solutions to the congestion problem are mentioned and evaluated. Peak load pricing is an awkward solution because of the geographic dimension of flights. We recommend instead a priority pricing system
Dracinschi, Anca. "Contrôle de congestion dans Internet : un mécanisme unifié pour prévenir la congestion des flots unicast et multicast". Paris 6, 2000. http://www.theses.fr/2000PA066145.
Pełny tekst źródłaSanhaji, Ali. "Nouveaux paradigmes de contrôle de congestion dans un réseau d'opérateur". Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/17304/1/sanhaji.pdf.
Pełny tekst źródłaChatté, Fabien. "Contribution au contrôle de congestion dans les protocoles de transport". Compiègne, 2004. http://www.theses.fr/2004COMP1514.
Pełny tekst źródłaLn this PhD thesis manuscript, we begin by presenting a panorama of different congestion control techniques implemented in unicast transport protocols. Next, we present a study in which we try to define the validity limits of the fluid approximation of a packets switched network. After, we describe and justify the development (in the continuous time domain) of a controller, which is used to compensate the sending rate of network sources in order to avoid congestions. Once the controller developed, we discretize it in order to implement it in a transport protocol. To objectively compare our congestion control mechanism to the existing ones, we define a comparison methodology. This methodology allows to evaluate performance of congestion control mechanisms. At the end, we compare the performance of our protocol with those of several existing transport protocols. This comparison allows us to analyse in several cases, the behaviour of the tested protocols
Raffarin, Marianne. "Le contrôle aérien en France : congestion et mécanismes de prix". Paris 1, 2002. http://www.theses.fr/2002PA010056.
Pełny tekst źródłaBoukhatem, Nadia. "L'approche multi-agents pour un contrôle de congestion adaptatif de réseaux atm". Versailles-St Quentin en Yvelines, 1998. http://www.theses.fr/1998VERS0021.
Pełny tekst źródłaViéron, Jérôme. "Codage scalable et contrôle de congestion pour transmission vidéo sur réseaux hétérogène". Rennes 1, 2003. https://hal.archives-ouvertes.fr/tel-01131930.
Pełny tekst źródłaBellache-Sayah, Thiwiza. "Contrôle dynamique des communications dans un environnement v2v et v2i". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV011/document.
Pełny tekst źródłaCooperative intelligent transport systems allow vehicles to communicate with each other as well as with the infrastructure in order to ensure the availability of information more reliably on vehicles, their positions and road conditions. This exchange of relevant information improves road safety, reduces traffic incidents and ensures efficient mobility of vehicles. IEEE 802.11p is standardized as the default technology for vehicle communications. In this context, the European ETSI standard addresses in particular road safety applications. To do this, it standardizes several types of messages such as CAM (Cooperative Awareness Message) and DENM (Decentralized Event Notification Message). CAMs are single-hop broadcast messages, sent by each vehicle containing information on its position, speed, direction, etc., in order to ensure lucid cooperation between other road users (including vehicles). The DENMs are sent when there is a detection of an event on the road, as in the case of an accident, traffic jams, etc. If necessary, multi-hop communication, using standardized routing algorithms, is implemented to disseminate these messages beyond the scope of the transmitter. The weakness of 802.11p lies in congestion of the radio channel due to the limited bandwidth (5.9 GHz). In order to compensate for this, ETSI proposed a framework for congestion control called DCC (Distributed Congestion Control). This allows the exchange of information, in particular the state of the radio channel, between the layers of the protocol stack. Thus, each communication protocol controls its own parameters to avoid congestion of the channel. In addition, many DCC congestion control approaches exist for CAM messages such as the control of the CAM generation period on the Facilities layer. Transmission power or data rate on the Access layer, etc. On the other hand, little works have been done on DENMs. In this regard, we proposed a DCC approach on the GeoNetworking layer which controls the routing parameters based on the state of the radio channel. An evaluation of the dual-DCC, namely CAM on Facilities and DENM on GeoNet, demonstrated the effectiveness of the proposed approach. In addition, some applications such as managing a fleet of vehicles require a localized control center that communicates with the fleet. For this type of exchange, a hybrid communication (IP and Geo) is necessary. Moreover, to ensure the fluidity of communication, the management of mobility is paramount. While remaining within the framework of the Mobile IP architecture, we propose our approach of addressing which constitutes a routable IP address with a geonetworking address, which makes it possible to deal with the problem of accessibility of vehicles moving on the road from of an entity on the Internet. Unlike Mobile IP, our approach reduces the overhead of signaling. This is done by partitioning the road into routing area (RA) in such a way that the access to the Internet is via a RSU-FA gateway that controls the RA. Each RA regroups a number of RSUs
Lucas, Vincent. "Contrôle de congestion équitable pour le multicast et interface avec le niveau applicatif". Phd thesis, Université de Strasbourg, 2010. http://tel.archives-ouvertes.fr/tel-00523422.
Pełny tekst źródłaChakroun, Omar. "Techniques de contrôle de congestion et de dissémination d'informations dans les réseaux véhiculaires". Thèse, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/5893.
Pełny tekst źródłaZiegler, Thomas. "Optimisation de l'équité et de l'efficacité du contrôle de la congestion dans l'Internet". Paris 6, 2000. http://www.theses.fr/2000PA066575.
Pełny tekst źródłaRouhana, Nicolas. "Architectures de contrôle de qualité de service". Paris 6, 2001. http://www.theses.fr/2001PA066368.
Pełny tekst źródłaTesta, Claudio. "Le contrôle de congestion dans les applications Pair-à-Pair : le cas de LEDBAT". Thesis, Paris, ENST, 2012. http://www.theses.fr/2012ENST0066/document.
Pełny tekst źródłaIn the last years, Internet delays are considerably growing, causing a performance deterioration of interactive applications. This phenomenon is getting worse with the increasing popularity of bandwidth-intensive applications, as video streaming, remote backup and P2P systems. The cause of these delays has been identified with the excess buffering inside the network, called “bufferbloat”. Research efforts in this direction head toward active queue management techniques and end-to-end congestion control. In this context, we investigated LEDBAT, a low-priority delay-based transport protocol introduced by BitTorrent. This protocol is designed to transfer large amount of data without affecting the delay experienced by other applications or users. First we analysed transport-level performance of LEDBAT using experimental measurement, simulation and analytical model. Specifically, we evaluated LEDBAT as is, comparing its performance to standard TCP or to other low priority protocols. We then identified a later-comer advantage and we proposed fLEDBAT, which re-introduces intra-protocol fairness maintaining the original LEDBAT objectives. Finally we studied the impact of the LEDBAT protocol on BitTorrent performance. Through simulations and real network experiments, we analysed how BitTorrent impacts on the buffer occupancy of the access node. BitTorrent performance was evaluated in terms of completion time, the main metric to assess the user quality of experience. Results showed that LEDBAT decreases the completion time with respect to standard TCP and significantly reduces the buffer occupancy, that translates in lower delays experienced by competing interactive applications
Testa, Claudio. "Le contrôle de congestion dans les applications Pair-à-Pair : le cas de LEDBAT". Electronic Thesis or Diss., Paris, ENST, 2012. http://www.theses.fr/2012ENST0066.
Pełny tekst źródłaIn the last years, Internet delays are considerably growing, causing a performance deterioration of interactive applications. This phenomenon is getting worse with the increasing popularity of bandwidth-intensive applications, as video streaming, remote backup and P2P systems. The cause of these delays has been identified with the excess buffering inside the network, called “bufferbloat”. Research efforts in this direction head toward active queue management techniques and end-to-end congestion control. In this context, we investigated LEDBAT, a low-priority delay-based transport protocol introduced by BitTorrent. This protocol is designed to transfer large amount of data without affecting the delay experienced by other applications or users. First we analysed transport-level performance of LEDBAT using experimental measurement, simulation and analytical model. Specifically, we evaluated LEDBAT as is, comparing its performance to standard TCP or to other low priority protocols. We then identified a later-comer advantage and we proposed fLEDBAT, which re-introduces intra-protocol fairness maintaining the original LEDBAT objectives. Finally we studied the impact of the LEDBAT protocol on BitTorrent performance. Through simulations and real network experiments, we analysed how BitTorrent impacts on the buffer occupancy of the access node. BitTorrent performance was evaluated in terms of completion time, the main metric to assess the user quality of experience. Results showed that LEDBAT decreases the completion time with respect to standard TCP and significantly reduces the buffer occupancy, that translates in lower delays experienced by competing interactive applications
Fraval, Nicolas. "Composants à cristaux liquides nématiques adressés par électrodes résistives en polymère conducteur et applications". Télécom Bretagne, 2010. http://www.theses.fr/2010TELB0146.
Pełny tekst źródłaThis work talks about the technological association of two materials which have remarkable electric and optical properties, liquid crystals (LC) and transparent conducting polymer PEDOT-PSS, applied to two different optical functions. LC Electrically tunable waveplates with quadripolar structures allows to modify the birefringence thanks to a fine control of the electric field orientation. This electrical addressing is made possible thanks to the use of high impedances inter-electrodes layers (~ 1 MΩ/) made with PEDOT-PSS which homogenize the electric field distribution in the cell. This structure guarantees an increase in the variation of optical path difference (~16 π at 633 nm) and shorter response times (20 µs) than classical nematic cells and higher pupils dimensions than the existing multipolar cells (100 x 500 µm). These performances are useful for applications which require high phase variations. The miniature needs for autofocus arouses a growing industrial interest as optoelectronics is democratized. LC lenses with modal control of the electric field represent the best solution, because of their low cost, quality and performances but remained limited to large pupils (> 5 mm) because of the lake of satisfying materials. The uses of PEDOT-PSS layers with very high impedance (10 MΩ/) has allowed us to overcome this restriction in order to carry out lenses without lower limits of pupils dimensions (D = 1,2,5 and 10 mm). The uniformity obtained for the surface distribution of the layer resistance enabled us to improve the properties of focusing (f = 2 cm to infinity). Thus the two applications developed in this work show the importance and the complementarity of these two key materials, LC and PEDOT-PSS, in the development of new electro-optical devices and open a broad field of applications
Silveira, Filho Fernando Jorge. "Unsupervised diagnosis of network traffic anomalies". Paris 6, 2010. http://www.theses.fr/2010PA066243.
Pełny tekst źródłaTrang, Si Quoc Viet. "FLOWER, an innovative Fuzzy LOWer-than-best-EffoRt transport protocol". Thesis, Toulouse, ISAE, 2015. http://www.theses.fr/2015ESAE0029/document.
Pełny tekst źródłaIn this thesis, we look at the possibility to deploy a Lower-than-Best-Effort(LBE) service over long delay links such as satellite links. The objective isto provide a second priority class dedicated to background or signalingtraffic. In the context of long delay links, an LBE service might also help tooptimize the use of the link capacity. In addition, an LBE service can enablea low-cost or even free Internet access in remote communities via satellitecommunication. There exists two possible deployment level of an LBE approach: either at MAClayer or at transport layer. In this thesis, we are interested in anend-to-end approach and thusspecifically focus on the transport layersolutions. We first propose to study LEDBAT (Low Extra Delay BackgroundTransport) because of its potential. Indeed, LEDBAT has been standardized byIETF and is widely deployed within the official BitTorrent client.Unfortunately, the tuning of LEDBAT parameters is revealed to highly depend onthe network conditions. In the worst case scenario, LEDBAT flows can starveother traffic such as commercial traffic performing over a satellite link.LEDBAT also suffers from an intra-unfairness issue, called the latecomeradvantage. All these reasons often prevent operators to allow the use of suchprotocol over wireless and long-delay link as a misconfiguration can overloadthe link capacity. Therefore, we design FLOWER, a new delay-based transportprotocol, as an alternative to LEDBAT. By using a fuzzy controller to modulatethe sending rate, FLOWER aims to solve LEDBAT issues while fulfilling the roleof an LBE protocol. Our simulation results show that FLOWER can carry LBEtraffic not only in the long delay context, but in a wide range of networkconditions where LEDBAT usually fails
Prabhu, Balakrishna J. "Chaînes de Markov et processus de décision markoviens pour le contrôle de congestion et de puissance". Phd thesis, Université de Nice Sophia-Antipolis, 2005. http://tel.archives-ouvertes.fr/tel-00328111.
Pełny tekst źródłaLochin, Emmanuel. "Transport des données et gestion de la congestion dans l'Internet de demain : du contrôle à l'anarchie". Habilitation à diriger des recherches, Institut National Polytechnique de Toulouse - INPT, 2011. http://tel.archives-ouvertes.fr/tel-00680719.
Pełny tekst źródłaAbdulmalak, Abdo. "Contrôle de congestion dans les réseaux locaux ATM : conception et validation de l'algorithme "Adaptive Leaky Bucket"". Toulouse 3, 1995. http://www.theses.fr/1995TOU30071.
Pełny tekst źródłaFortat, Vivien. "Coordination of individual choices and congestion in networks : experimental studies". Rennes 1, 2011. http://www.theses.fr/2011REN1G005.
Pełny tekst źródłaToday, networks are necessary to our society; we need them to provide access to fundamental needs like energy, transportation, natural resources or information. The main problem for those networks is that they might have to face congestion, resulting in a decrease of the users’ quality or even a failure of the network. In this thesis, several experimental studies will be presented. In the first chapter, the literature related to the topic is presented. In chapter two, we built a theoretical model of market entry game where congestion cost increases at a higher rate when the flow of entrants grows (snowball effect). We find no significant difference between the aggregated entry rates in our snowball game compared to usual MEG. For our third chapter, we have conducted an experiment aiming to analyze how agents coordinate their usage of a limited resource. Several ways to make users face congestion were tested. It appeared that on all treatments, players were unable to successfully coordinate on Nash equilibrium. We also observed that providing more precise information did not help to increase cooperation. Offering two pricing systems including a safe one increased average consumption while excluding biggest consumers in case of congestion significantly reduce average group consumption and also limited extreme value of consumption (low or high). In the fourth chapter, we studied how a regulator can influence social norm by implementing different policies. This experiment was conducted in Japan and France. We find that creating socially optimum social norm required to give enough incentive to cooperate to agents, but also required a strong impact on agents’ beliefs
Arouk, Osama. "Cellular-based machine-to-machine : congestion control and power management". Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S112/document.
Pełny tekst źródłaThe current and next generation wireless cellular networks (5G) have to deal with not only communications between people (known as Human-to-Human - H2H), but also with a massive deployment of Machine-Type-Communication (MTC). MTC, or alternatively Machine-to-Machine (M2M), can be viewed as devices connected among them without any human intervention. M2M can be considered as the cornerstone of Internet-of-Things (IoT) vision. It attracts a lot of attention, since it can be considered as a new opportunity and business market. Nowadays, there is a vast number of MTC applications, covering a large number of fields. Some of these applications are Healthcare, Intelligent Transport System (ITS), smart metering and smart grids, public safety (PS), forming the so-called smart city. Deploying this type of applications in the current cellular mobile networks, especially Long Term Evolution (LTE) and LTE-Advanced (LTE-A), cannot be achieved before overcoming the accompanied challenges. Indeed, caused by the existence of a myriad of MTC devices, Radio Access Network (RAN) and Core Network (CN) congestion and system overload is one of these challenging issues. As the MTC devices are using non-rechargeable batteries, power consumption is also a challenge. In this thesis, we study the congestion and power consumption problems in the context of LTE and LTE-A networks featuring M2M communications. Regarding the congestion and system overload, the focus will be on the RAN part since it can be considered as the first defense line on the network. The contributions of the thesis are organized on the following axes: 1) Propose a general algorithm to predict the incoming traffic, so that the congestion in the network can be easily remedied, 2) Study and propose a general analytical model of the Random Access Channel (RACH) procedure. The model can help to evaluate the congestion control methods targeting the RAN part, 3) Depth study and propose methods improving the performance of Group Paging (GP) method, one of the methods approved by 3GPP to control the congestion
El, Fawal Ahmad Hani. "Machine-to-machine communication congestion mechanism". Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2018. http://www.theses.fr/2018ENTA0010/document.
Pełny tekst źródłaThis Ph.D. work aims to study the Machine-to-Machine (M2M) congestion overload problem and the mutual impact among M2M and Human-to-Human (H2H) traffics in IoT (Internet of Things) environments specifically during disaster events. M2M devices with their expected exponential booming in the near future, will be one of the significant factors to influence all mobile networks. Inevitably, the expected huge number of M2M devices causes saturation problems, and leads to remarkable impacts on both M2M and H2H traffics, services and applications. To study the M2M and H2H mutual influences, we create a new platform model based on Continuous-Time Markov Chain (CTMC) to simulate, analyze and measure radio access strategies due to the limitations of existing Long Term Evolution-Advanced (LTE-A) simulators (i.e, SimuLTE) in term of massive M2M devices, parameter flexibility and statistical tools. Additionally, during disaster events, a fast bandwidth depletion of the limited bandwidth assigned to M2M devices in Long Term Evolution for Machines (LTE-M) and Narrow Band for IoT (NB-IoT) networks is expected due to the high arrival request of M2M device network access. To address this problem, we propose a new approach named Adaptive eNodeB (A-eNB) for both LTE-M and NB-IoT networks. The A-eNB can solve gradually the overload problem, while keeping the H2H traffic Quality of Service (QoS) not to be affected badly. The network adaptation is provided through a dynamic LTE-M resource reservation aiming to increase the number of M2M connections accessing the LTE-M/NB-IoT network and to decrease the impact on H2H traffic
Yang, Furong. "Towards Efficient Transport Mechanisms in Mobile Internet : Measurement and Optimization". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS341.
Pełny tekst źródłaThe transport performance in Mobile Internet is crucial to user experience and directly affects the revenue of providers for Internet applications. This dissertation focuses on network access and congestion control, two key factors affecting transport performance, and conducts research from three aspects: network access measurement, single-path congestion control, and multipath congestion control. For network access measurement, we conduct a measurement study across four cities to analyze the characteristics of the connectivity based on provider-managed WiFi in mobile scenarios. For single-path congestion control, we propose an enhanced BBRv2 algorithm based on delay information to improve the performance of BBRv2 in mobile scenarios. For multipath congestion control, we propose a multipath congestion control algorithm (CCA) selection mechanism, which leverages machine learning to dynamically select suitable CCAs for subflows to improve the performance of multipath transport
Corbel, Romuald. "Évolution des protocoles de transport du point de vue de l'équité". Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2019. http://www.theses.fr/2019IMTA0160.
Pełny tekst źródłaThis thesis is in the context of measuring congestion on the network and the evolution of transport protocols. Changes are continually being made to meet the needs of users and new services. Congestion is one of the most critical issues because it has an impact on the performance of Internet networks, hence the need for congestion control algorithms to prevent or remove it. Today, no algorithm perfectly meets the expected requirements, and a lot of research is underway. Nevertheless, these new algorithms can affect network fainress since the behaviour of the transport protocol can change radically depending on the congestion control algorithm used in the endpoints. In addition, in recent years, transport protocols have undergone major changes. A recent significant exampleis Quick UDP Internet Connections (QUIC), a protocol introduced by Google, which aims to replace two widely used transport and security protocols, Transmission Control Protocol (TCP) and Transport Layer Security (TLS). QUIC is implemented in user applications (rather than in the operatingsystem kernel). It is designed to be resistant to ossification and therefore more versatile. This makes content providers, such as Google, hegemonic about the data rate of their users. Due to the progressive development of congestion control algorithms and the evolving nature of transport protocols, new challenges arise in fairness management. This is why, in this thesis, we focused on the development of a test platform to measure network fairness based on the flow rate of the different flows. In addition, in order to characterize fairness as perceived by a user, we focused on determining an impartial procedure for assessing fainress during an entire session of a transport flow (called Session Fairness Assessment(SFA) and Weighted Session Fairness Assessment(WSFA)). Based on these elements, we specifically analyzed the fairness of the protocols when TCP and QUIC flows coexist on a fixed and mobile network. In our fairness assessments, weidentified the impact of aspects of QUIC implementation such as: emulating multiple TCP connections, limiting the size of congestion windows and using the hystart option. The results show that these mechanisms have a strong influence on fairness on both fixed and mobile networks. Indeed,a wrong setting of the default parameters of these mechanisms or the activation of the hystart option can affect the performance of transport protocols and therefore fainress. With regard to the evaluation of congestion control algorithms, the results show that the fainress between two different algorithms depends on the network configuration. This conclusion demonstrates that a measurement procedure, such as the one presented in this thesis, is relevant to conducting the fairness assessment. In this thesis we can conclude that the lack of standardization, for example of emulating multiple TCP connections in QUIC, leads us to question more broadly how QUIC’s design philosophy takes fairness into account. In addition, the results obtained on the evaluation of the fainress of congestion control algorithms allow us to question the fainress evaluation of several contributions when it is not tested in enough network configurations
LARRIEU, Nicolas. "Contrôle de congestion et gestion du trafic à partir de mesures pour l'optimisation de la QdS dans l'internet". Phd thesis, INSA de Toulouse, 2005. http://tel.archives-ouvertes.fr/tel-00009745.
Pełny tekst źródłaAriba, Yassine. "Sur la stabilité des systèmes à retards variant dans le temps : théorie et application au contrôle de congestion d'un routeur". Phd thesis, Université Paul Sabatier - Toulouse III, 2009. http://tel.archives-ouvertes.fr/tel-00442454.
Pełny tekst źródłaLarrieu, Nicolas. "Contrôle de congestion et gestion du trafic à partir de mesures pour l'optimisation de la qualité de service dans l'Internet". Toulouse, INSA, 2005. http://www.theses.fr/2005ISAT0007.
Pełny tekst źródłaInternet monitoring has only been used for research, engineering and design of Internet networks since few years (since the beginning of years 2000), but it is more and more popular and spreads rapidly. It deals with studying, characterizing, analyzing and modeling traffic on the different Internet links in order to understand network behaviors when facing traffics which are largely unknown at this time. In particular, guarantying QoS for the Internet is currently one of the most challenging issues. This thesis aims at designing new communication protocols and architectures able to reduce the traffic LRD in order to optimize the use of communication resources. Then, new protocol and architectural mechanisms could be perfectly suited to users’ needs and traffic constraints. Thus, this PhD work deals with a new approach for the Internet, aiming at improving traffic management, QoS and more generally network services. This approach, called Measurement Based Networking (MBN), is built on the use of active and passive monitoring techniques to evaluate in real time different network parameters and analyze its traffic in order to react very quickly and accurately to specific events arising in the network (for instance, congestion events). We will illustrate, in particular, the MBN approach by designing a new measurement based congestion control mechanism (MBCC) which will be evaluated thanks to NS-2 simulations. We will show, in particular, how this new mechanism can improve traffic characteristics as well as Internet QoS, despite the complexity and variability of current Internet traffics
Medina, Ruiz Hamlet. "TCP and network coding : equilibrium and dynamic properties". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112165.
Pełny tekst źródłaCommunication networks today share the same fundamental principle of operation: information is delivered to their destination by nodes intermediate in a store-and-forward manner.Network coding (NC) is a technique that allows intermediate nodes to send out packets that are linear combinations of previously received information. The main benefits of NC are the potential throughput improvements and a high degree of robustness, which is translated into loss resilience. These benefits have motivated deployment efforts for practical applications of NC, e.g., incorporating NC into congestion control schemes such as TCP-Reno to get a TCP-NC congestion protocol. In TCP-NC, TCP-Reno throughput is improved by sending a fixed amount of redundant packets, which mask part of the losses due, e.g., to channel transmission errors. In this thesis, we first analyze the dynamics of TCP-NC with random early detection (RED) as active queue management (AQM) using tools from convex optimization and feedback control. We study the network equilibrium point and the stability properties of TCP-Reno when NC is incorporated into the TCP/IP protocol stack. The existence and uniqueness of an equilibrium point is proved, and characterized in terms of average throughput, loss rate, and queue length. Our study also shows that TCP-NC/RED becomes unstable when delay or link capacities increases, but also, when the amount of redundant packets added by NC increases. Using a continuous-time model and neglecting feedback delays, we prove that TCP-NC is globally stable. We provide a sufficient condition for local stability when feedback delays are present. The fairness of TCP-NC with respect to TCP-Reno-like protocols is also studied. Second, we propose an algorithm to dynamically adjust the amount of redundant linear combinations of packets transmitted by NC. In TCP-NC with adaptive redundancy (TCP-NCAR), the redundancy is adjusted using a loss differentiation scheme, which estimates the amount of losses due to channel transmission errors and due to congestion. Simulation results show that TCP-NCAR outperforms TCP-NC in terms of throughput. Finally, we analyze the equilibrium and stability properties of TCP-NCAR/RED. The existence and uniqueness of an equilibrium point is characterized experimentally. The TCP-NCAR/RED dynamics are modeled using a continuous-time model. Theoretical and simulation results show that TCP-NCAR tracks the optimal value for the redundancy for small values of the packet loss rate. Moreover, simulations of the linearized model around equilibrium show that TCP-NCAR increases the size of the TCP-Reno stability region. We show that this is due to the compensator effect of the redundancy adaptation dynamics to TCP-Reno. These characteristics of TCP-NCAR allow the congestion window adaptation mechanism of TCP-Reno to react in a smooth way to channel losses, avoiding some unnecessary rate reductions, and increasing the local stability of TCP-Reno
Zhong, Zhenzhe. "Cross-layer congestion control and quality of services in mobile networks". Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT022.
Pełny tekst źródłaThe mobile network is a hybrid network with Radio Access part and the fixed backhaul core network. The congestion control algorithms(CCA) designed for a specific type of system may not work as well in the other kind of network, especially the network with hybrid feature device like the mobile edge network. Generally, the bottleneck in a mobile network is the Radio access part. However, this is not always the case since multiple radio base stations or packet delivery network gateway can be sharing the same bottleneck in the packet delivery backhaul. In this thesis, we start from a cross-layer method and address the issue with a ubiquitous solution. The first algorithm we analysed is called CQIC, which get the PHY layer of UE involved in the congestion control design. An improvement from 3G CQIC to LTE scenario is proposed named DCIC. This algorithm uses the Downlink Control Indicator(DCI) instead of Channel Quality Indicator(CQI) to save the computation power on UE and take the scheduling result of eNB into consideration. Further, we evaluated current BBR algorithm, which focuses on the data centre network, in the mobile scenario. Most conventional CCA does not take the uplink BW degradation and other features in the cellular system into consideration in its bandwidth estimation method. Based on the review, we proposed the five tradeoff objectives to guide the CCA design in a mobile hybrid type of network: Bandwidth Utilisation, Delay (where loss is the extreme expression of delay), Fairness, Simplicity and Genericity. Based on the tradeoffs and goals, we proposed CDBE, a TCP clientside driven bandwidth estimation(CDBE) and report feedback loop. The client-side BW estimation method takes only little computation capability in the second version, compared to its first version and the DCIC. Cooperate with the enhanced server-side state transition CDBE can achieve a fair share of BW in both fixed packet core network or mobile network with a lower cost of RTT compared to conventional CCAs. No extra middlebox or edge computing unit/applications is required in CDBE architecture
Zhang, Xiaofei. "Contrôle de transmission multi-chemin et gestion de mobilité pour protocoles de transport multihoming". Paris 6, 2012. http://www.theses.fr/2012PA066130.
Pełny tekst źródłaMost of mobile devices today are equipped with multiple network interfaces that could be connected to different network and obtain multiple IP addresses. In this dissertation, we investigate the multihoming problems at transport layer to improve the end-to-end performance in wireless networks. Moreover, the coordination between multihoming and mobility management is studied which permit us to propose a cooperative mobility management for an environment Post-IP. Firstly, we propose a cross-layer solution for performance optimization with the Concurrent Multipath Transfer (CMT) extension of SCTP in wireless networks. Two parameters, Frame Error Rate (FER) at the link layer and Round Trip Time (RTT) at the transport layer are used to evaluate the path conditions. The simulation results show that our proposal improves the goodput. Secondly, we focus on the heterogeneous wireless links. We chose Kalman filter for the estimation of path conditions. The simulation results show that our proposal reduces the reordering degree and increases the total goodput. Finally, a cooperative mobility management architecture is proposed for Post-IP. Multihoming and end-to-end features are analyzed to present the proposal of Multihoming-based Cooperative Mobility Management (MCMM). The cooperative mobility management optimizes the handover delay in the heterogeneous access networks. The MCMM is implemented in C++ under Linux with a test-bed. The experimental results show that the handover delay can be reduced by sending update messages over the interface of the fastest path
Zeng, Xuan. "Vers une mobilité transparente dans le réseau ICN : connectivité, sécurité, et fiabilité". Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS046.
Pełny tekst źródłaWith the proliferation of mobile devices, mobility becomes a requirement and a compelling feature for 5G. However, despite tremendous efforts in the last 2 decades to enable mobility in IP network, the solutions are mostly anchor-based and inefficient. In this context, Information-Centric networking (ICN) is proposed. While ICN has some native support of mobility, other architectural challenges remain unsolved to achieve seamless mobility. The thesis explores 3 main challenges of such and contributes novel solutions. First, to solve producer mobility, MapMe, a micro mobility management protocol supporting latency sensitive traffic is proposed. MAP-Me is anchorless and preserves key ICN benefits. Simulation results show that MAP-Me outperforms existing work in user performance while retaining low network overheads in various network conditions. Second, we investigate security in producer mobility. We focus on prefix hijacking attack, which is a basis of several attacks. To prevent prefix hijacking, we propose a light-weight and distributed prefix attestation protocol based on hash-chaining. First results show significant improvement in verification overhead. It is resistant to replay-based prefix hijacking. Finally, additional transport-layer mechanisms are needed in mobile ICN. To this aim, we investigate alleviating the adverse effect of wireless/mobility loss on congestion control. We propose WLDR and MLDR for in-network loss detection and recovery to facilitate congestion control. Simulation results show a significant reduction in flow completion time (up to 20%)
Luu, Thanh Tra. "Etude et mise en oeuvre d'une signalisation IP universelle". Paris, ENST, 2006. http://www.theses.fr/2006ENST0046.
Pełny tekst źródłaThe future generation of the Internet requires a powerful control plane wherein the signaling plays a key role in enabling information exchanges between the network elements to provide the existing and future network services. The thesis develops a generic IP signaling protocol, referred to as GISP, which provides common functionalities required by most IP signaling protocols including state management, transport and security services. The GISP implements a soft-state approach to manage the signaling states established within the network elements. In particular, a new soft-state management mechanism is proposed to significantly reduce the signaling traffic as well as the CPU resource consumption allowing the GISP to meet scalability in the number of signaling sessions. The GISP supports the signaling messages transport between the network elements. A variety of transport services have been specifically developed for GISP such as message bundling, message fragmentation, path MTU discovery, partially reliable transport and congestion control. These services have been designed to provide performance, flexibility and robustness for the generic signaling protocol. Finally, the GISP provides security services to protect the message transport as well as the network from vicious attacks. A GISP implementation has been realized in the context of the thesis to experience the GISP functionalities and evaluate its performance aspects
Zeng, Xuan. "Vers une mobilité transparente dans le réseau ICN : connectivité, sécurité, et fiabilité". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS046/document.
Pełny tekst źródłaWith the proliferation of mobile devices, mobility becomes a requirement and a compelling feature for 5G. However, despite tremendous efforts in the last 2 decades to enable mobility in IP network, the solutions are mostly anchor-based and inefficient. In this context, Information-Centric networking (ICN) is proposed. While ICN has some native support of mobility, other architectural challenges remain unsolved to achieve seamless mobility. The thesis explores 3 main challenges of such and contributes novel solutions. First, to solve producer mobility, MapMe, a micro mobility management protocol supporting latency sensitive traffic is proposed. MAP-Me is anchorless and preserves key ICN benefits. Simulation results show that MAP-Me outperforms existing work in user performance while retaining low network overheads in various network conditions. Second, we investigate security in producer mobility. We focus on prefix hijacking attack, which is a basis of several attacks. To prevent prefix hijacking, we propose a light-weight and distributed prefix attestation protocol based on hash-chaining. First results show significant improvement in verification overhead. It is resistant to replay-based prefix hijacking. Finally, additional transport-layer mechanisms are needed in mobile ICN. To this aim, we investigate alleviating the adverse effect of wireless/mobility loss on congestion control. We propose WLDR and MLDR for in-network loss detection and recovery to facilitate congestion control. Simulation results show a significant reduction in flow completion time (up to 20%)
Achir, Nadjib. "Distribution de la vidéo multi-objets dans les réseaux hétérogènes". Paris 6, 2003. http://www.theses.fr/2003PA066499.
Pełny tekst źródłaJaber, Mohamad. "Internet traffic profiling identification". Nice, 2011. http://www.theses.fr/2011NICE4085.
Pełny tekst źródłaThe evolution of the Internet in the last few year has been characterized by dramatic changes in the way users behave, interact and utilize the network. This was accompanied by the introduction of new categories of applications such as network games and peer-to-peer services. One of the most important challenges for network administrators and ISPs is then becoming the identification of Internet traffic applications in order to protect their resources from unwanted traffic and to prioritize some major applications. Statistical methods are preferred to port-based ones and deep packet inspection since they donât rely on the port number and they also work for encrypted traffic. Theses methods combine the statistical analysis of the application packet flow parameters, such as packet size and inter-packet time, with machine learning techniques. However, the majority of these statistical methods cannot identify flows early and require reaching the end of flows before taking any decision which is considered as too late for network administrators ; indeed they do not provide means to stop an Internet flow or to give it a special quality of service early in its lifetime. Another important challenge for network administrators is to detect and diagnose key network changes as a long-term congestion, a rerouting, a link failure or any other even causing a shift in network delays. In the literature there is a huge amount of anomaly detection methods but most of them require exhaustive measurements to function properly. Reducing the load of network-wide monitoring is always a vital need for network administrators. In this thesis we present several contributions around Internet traffic identification and network-wide anomaly detection. In the first part we present three methods we have developed in order to identify accurately and on the fly the Internet traffic. The first method is a new online iterative probabilistic method that identifies applications quickly and accurately by only using the size of the first N packets. The second method enhances the first one with the inter-packet time in order to identify Internet traffic, this has required the introduction of a model to isolate the noise due to network conditions and to extract the time generated by the applications themselves. Our third method is a new online method for traffic classification that combines the statistical and host-based approaches in order to construct a robust and precise method for early Internet traffic identification. We use the packet size as the main feature for the classification and we benefit from the traffic profile of the host (i. E. Which application and how much) to decide in favour of this or that application. In the second part of this thesis, we aboard the problem of network-wide anomaly detection. We start by making a study about the stability of Internet coordinate systems (especially Vivaldi). In a first stage we confirm the fact that Vivaldi coordinates are most of the time correlated with each other pointing to a stable cluster of nodes seen from inside the network. In a second stage, we present a new clustering algorithm based on the data mining Hierarchical Grouping method to identify this cluster of stable nodes. Finally, we highlight the utility of such finding with and application that tracks changes in network delays. By changing artificially the network delays in different scenarios, we show that these changes are easily reflected by this body of stable nodes, hence allowing to obtain a global picture about the stability of the underlying network without the need for exhaustive delay measurements
Valenti, Silvio. "La gestion du trafic P2P dans les réseaux modernes : mesure, identification et contrôle". Phd thesis, Télécom ParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-00645263.
Pełny tekst źródłaValenti, Silvio. "La gestion du trafic P2P dans les réseaux modernes : mesure, identification et contrôle". Phd thesis, Paris, Télécom ParisTech, 2011. https://pastel.hal.science/pastel-00645263.
Pełny tekst źródłaDue to the large diffusion of P2P applications and especially P2P live-streaming, P2P traffic occupies an extremely large portion of overall Internet traffic. In this context, this thesis proposes new instruments to measure, identify and control P2P traffic. Regarding traffic classification, since traditional techniques have a hard time identifying P2P traffic, we propose a new behavioral classifier, Abacus, tailored for P2P live-streaming. Our experiments prove that Abacus, though based on simple counts of packets and bytes exchanged by a host, represents a lightweight and accurate solution for identifying P2P applications. Second, since the huge volume of traffic obliges operators to employ either flow-level monitors (e. G. NetFlow) or packet sampling to cut down the amount of measurement data, we evaluate the impact of data reduction on traffic characterization and classification. We show that Abacus can be adapted to this kind of data, suffering only a minor loss in accuracy and statistical classification remains possible if training and validation data are sampled at the same rate, in spite of the distortion introduced by packet sampling. Finally, we study a new transport protocol for P2P traffic, LEDBAT (Low Extra Delay Background Transport Protocol), the congestion control algorithm of the official BitTorrent client. This delay-based algorithm aims to provide an efficient, lower-than-best-effort service. Though faithful to its goals, the original design of LEDBAT appears affected by a latecomer advantage: we identify the main cause of the unfairness and propose effectives correction that restore the fairness
Vergnol, Arnaud. "Intégration dans le réseau électrique et le marché de l’électricité de production décentralisée d’origine renouvelable : gestion des congestions locales". Thesis, Ecole centrale de Lille, 2010. http://www.theses.fr/2010ECLI0014/document.
Pełny tekst źródłaDevelopment of wind generation is a mean towards global warming reduction. However, in some parts of the electrical grid, the massive integration of renewable generation can lead to congestion problems. These congestions are related to the impossibility for the power grid to transport the generation. Nowadays, congestion management methods are based on day(s)-ahead computation of generation restriction which leads to important production losses for renewables. Based on this context, it’s therefore important to develop a methodology which is optimal, reliable and non-discriminatory for renewable.In this work, the proposed congestion management method is based on corrective actions. These actions are computed in real-time using regulation loops and Petri net-based algorithms. A stability study proved that gain margins are sufficient to assure the stability of the corrective actions. The algorithm allows an optimal selection of the generators than will participate in the congestion management. This selection is based on their cost and efficiency for congestion alleviation. Simulation results using the software EUROSTAG have shown the efficiency of the method and its adaptability to different generator types. Furthermore, general conclusions on congestions costs according to different regulations on the renewable generation were obtained
Vergnol, Arnaud. "Intégration dans le réseau électrique et le marché de l'électricité de production décentralisée d'origine renouvelable : gestion des congestions locales". Phd thesis, Ecole Centrale de Lille, 2010. http://tel.archives-ouvertes.fr/tel-00586084.
Pełny tekst źródłaBitam, Melha. "Modélisation et étude de comportement d'une ligne de communication TCP/IP". Phd thesis, Université Joseph Fourier (Grenoble), 2005. http://tel.archives-ouvertes.fr/tel-00092564.
Pełny tekst źródładiversifié aussi bien pour les industriels, les banques, la recherche, pour des particuliers et récemment
dans la médecine et la commande à distance. A cette forte utilisation des réseaux
viennent s'ajouter des contraintes de performances, de sécurité et de qualité de service que les
fournisseurs de service se doivent de respecter. L'étude des performances des réseaux ainsi que
leur modélisation exacte est donc un pas important pour la connaissance des influences des
différents liens des lignes de transmission sur les données qui les traversent. Afin d'évaluer l'in-
fluence des réseaux de communication dans la transmission des données, nous proposons de
modéliser puis d'étudier une ligne de transmission TCP/IP soumise aux protocoles de contrôle
de congestion et plongée dans un environnement Internet. L'outil de modélisation utilisé est les
RdP hybrides. Un modèle a été établi à base duquel toutes les dynamiques peuvent être observées
à tous les niveaux d'une communication (charge des buffers, baisse des vitesses à l'entrée
des routeurs, séparation des flux par les routeurs, priorités, stockage des données, retards, pertes,
etc.). Ce modèle détaillé nous a aussi permis de visualiser directement l'effet des changements
de paramètres de la ligne et des protocoles sur l'évolution de la transmission sur la ligne : Un
large panel de simulations a donc été effectué afin de visualiser ces différentes performances.
Enfin, un travail d'amélioration du temps de détection des pertes sur une ligne a été effectué.
Khan, Mohammad Irfan. "Multi-Service Resource Orchestration for Vehicular Safety Communications". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS639.
Pełny tekst źródłaWireless channel congestion control and decentralized resource allocation for 802.11p based V2X communication have been widely investigated for a single Cooperative Awareness service, considering mostly homogenous communication requirement per vehicle. Future connected vehicles will be based on multiple V2X services, with heterogenous number of services and communication needs, which existing resource allocation mechanisms does not address. In this thesis, we analyze several decentralized congestion control and channel resource allocation protocols standardized in Europe for initial V2X deployment. We present issues with the existing approach, in particular the inefficient channel capacity utilization, problematic cross layer coordination, inability to balance resources among multiple V2X safety services and distributed resource allocation for asymmetric number of services per vehicle. We propose improvements to the shortcomings, considering the requirements of future V2X scenarios. We demonstrate the limitations of classifying V2X services using static priority for Quality of Service and propose dynamic prioritization. We design a resource orchestrator at the Service Layer to improve cross layer coordination and dynamically distribute the limited channel resource among multiple services of a vehicle. Furthermore, we present a mechanism to decentrally orchestrate channel resource among a mixed distribution of vehicles with diverse channel usage requirements under channel congestion. Analytical and simulation-based results show the validity of our proposed approach, and the V2X application performance improvement it renders, compared to existing standardized protocols
Janczukowicz, Ewa Czeslawa. "QoS management for WebRTC : loose coupling strategies". Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2017. http://www.theses.fr/2017IMTA0010/document.
Pełny tekst źródłaThe number of real-time Over-The-Top (OTT) communication services has increased in the recent years. OTT solutions use the best-effort Internet delivery and rely on mechanisms built into the endpoints to adapt to underlying network fluctuations. Nevertheless, it is questionable if this approach is enough to provide acceptable quality of communication regardless the network conditions. Therefore, can network assistance be used to improve the quality of OTT real-time communication services?To address this question, we study OTT solutions with a focus on WebRTC. We identify three loose coupling strategies that leverage network mechanisms for improving OTT communication services quality.We verify the pertinence of these coupling strategies in the context of traffic management. We identify two approaches of traffic management solutions adapted to WebRTC traffic: 1) aiming at assuring lower queuing delays regardless the traffic or 2) isolating the sensitive traffic. We study the impact of identified traffic management solutions on WebRTC for wireline access networks (uplink, ADSL and fiber). The obtained results show that current Internet engineering practices are not well adapted to the WebRTC traffic, but are optimized for TCP traffic. Furthermore, the proposed solutions ensure more fairness between WebRTC and TCP flows and consequently enable avoiding WebRTC traffic starvation and improve the overall quality of the communication.In the final analysis, the evaluated traffic management solutions are positioned in the context of identified coupling strategies. Based on this assessment, we provide recommendations of improving WebRTC quality with the assistance of NSP
Girardet, Brunilde. "Trafic aérien : détermination optimale et globale des trajectoires d'avion en présence de vent". Thesis, Toulouse, INSA, 2014. http://www.theses.fr/2014ISAT0027/document.
Pełny tekst źródłaIn the context of the future Air Traffic Management system (ATM), one objective is to reduce the environmental impact of air traffic. With respect to this criterion, the “freeroute” concept, introduced in the mid 1990’s, is well suited to improve over nowadays airspace based ATM. Aircraft will no longer be restricted to fly along airways and may fly along fuel-optimal routes. The objective of this thesis is to introduce a novel pretactical trajectory planning methodology which aims at minimizing airspace congestion while taking into account weather conditions so as to minimize also fuel consumption.The development of the method was divided in two steps. The first step is dedicated to compute a time-optimal route for one aircraft taking into account wind conditions. This optimization is based on an adaptation of the Ordered Upwind Method on the sphere.The second step introduces a hybrid algorithm, based on simulated annealing and on the deterministic algorithm developed in the first step, in order to minimize congestion. Thus the algorithm combines the ability to reach a globally-optimal solution with a local-search procedure that speeds up the convergence