Dissertations / Theses on the topic 'QoS'
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1
Islam, Mohammad Shahidul, and Syed Nasir Mehdi. "How Different QoS Mechanisms Affect VoIP QoS Metrics." Thesis, Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-15337.
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Voice over Internet Protocol (VoIP) has become a key technology of communication. Our work has been a practical implemenation of different scenarios to show that VoIP voice quality can be improved by adopting certain Quality of Service(QoS) measures such as classification, marking or queuing. It has been discussed that different QoS metrics like delay, packet loss and jitter could affect the voice quality of VoIP. To reduce the negative affects, one option is to implement certain QoS mechanisms with some set of configurations. For this purpose, Cisco IP phones have been configured in our topology with routers, switches, traffic generators, end stations and VoIP quality monitoring software called VQmanager. Tests have been divided into two sets. In one test a fixed bandwidth of 70 kbps is set while in the other test a random bandwidth is set with trafic generators unleashing packets of traffic. In both these tests further scenarios with configurations are worked out. They include no QoS, Auto Qos and Customized Qos mechanisms. Results have been indicative of top performance by the Customized QoS mechanism, in both sets of tests, followed by Auto QoS and no QoS mechanisms. It has been observed that a customized scenario could be a particular configuration to any organization’s needs and that will have the lowest delay, jitter and packet loss which are the main QoS metrics that impact the voice quality of VoIP. It can be fundamentally composed of classification of voice, data or web-traffic, marking and queuing depending upon the need of the organization. It is finally suggested to carry more tests in companies to get more data for analysis
2
Stensen, Julianne M. G. "Evaluating QoS and QoE Dimensions in Adaptive Video Streaming." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for telematikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18998.
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The focus of this thesis has been on Quality of Service (QoS) and Qualityof Experience (QoE) dimensions of adaptive video streaming. By carryingout a literature study reviewing the state of the art on QoS andQoE we have proposed several quality metrics applicable to adaptivevideo streaming, amongst them: initial buffering time, mean duration of arebuffering event, rebuffering frequency, quality transitions and bitrate. Perhapscounterintuitively, other research has found that a higher bitratedoes not always lead to a higher degree of QoE. If one look at bitrate inrelation to quality transitions it has been found that users could prefer astable video stream, with fewer quality transitions, at the cost of an overallhigher bitrate. We have conducted two case studies to see if this isconsidered by today’s adaptive video streaming technologies. The casestudies have been performed by means of measurements on the playersof Tv2 Sumo and Comoyo. We have exposed the players to packet lossand observed their behavior by using tools such as Wireshark. Our resultsindicate that neither player take the cost of quality transitions intoaccount in their rate adaptation logic, the players rather strive for a higherquality level. In both cases we have observed a relatively large numberof quality transitions throughout the various sessions. If we were to giveany recommendations to the Over-the-Top (OTT) service providers, wewould advise them to investigate the effects of quality transitions andconsider including a solution for handling potentially negative effects inthe rate adaptation logic of the player.
3
Gholamzadeh, Shirmohammadi Bamshad. "Relationships between Quality of experience and TCP flag ratios for web services." Thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1031.
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Context: Nowadays one of the most beneficial business in IT area is web services with huge amount of users. The key ofsuccess in these type of services is flexibility in terms of providing same quality of services (QoS) and ability of fasttroubleshooting when number of users increase rapidly. To achieve these targets, evaluation of the user satisfaction is highlyessential. Moreover it is required to link user dissatisfaction to QoS parameters in terms of troubleshooting. Objectives: The main aim the research is to find an intelligent method for evaluation of the user satisfaction. The method isproposed to estimate quality-of-experience (QoE) without asking users to send their feed back. Connecting to this aim, thesecond target is finding the definition of function in equations of QoS=function(QoE). And finally, comparison of theimpact of QoS parameters on mobile application users and web site users is the last objective. Methods: For this research a web-server for video sharing propose is designed. The users can use it via web site or anAndroid mobile application. The three main QoS parameters (Packet-loss, delay and throughput) are changed gradually. Theusers are asked to score the mobile application and web site at the same time. In parallel the traffic of web-server is capturedand analyzed. Then based on variations in mean opinion scores (MOS) and also changes in TCP flags, the proper patternsfor each of the QoS parameters is provided. In this part the QoE is linked to transport layer. For the second objective, theQoE is directly linked to QoS. On the other words the graphs with QoE as horizontal axis and one of the QoS parameters asvertical axis are provided. And finally based on the gradient of these trends, the amount of impact of QoS parameters onmobile application users and web site users is compared. Results: Based on the results of the research, decrement in SYN and FIN flags and increment in ACK is an alarm for downgoing user satisfaction. In this situation, the problem is belongs to packet-loss. Increasing in the percentage of SYN is alsoa signal for user dissatisfaction. In this case, the problem is result of delay. And finally if the web-server problem is aboutthroughput then, SYN, FIN and ACK has up going trends. In all of the cases the rest of TCP flags has not clear up going ordecreasing trend.The correlation between QoS and QoE is formulated. The trends of MOS relative to QoS parameters for mobile phone andlaptop are very similar in case of packet-loss. For throughput the mobile phone users are a little more sensitive. The mostsignificant difference between the MOS values for mobile application and web site is belongs to delay. The increment indelay has really big negative effect on mobile application users. Conclusion: The final method for user satisfaction evaluation is based on the way of variations in the TCP flags. Among allthe flags, SYN, FIN and ACK passed the criteria to make the patterns. Moreover the method indicate the problem isbelongs to which of the QoS parameters. The correlation between QoE and QoS is formulated. And finally according tothese formulas, two separate web-servers for mobile application and web site is recommended.
4
Chowdhury, Md Kamal Hossain. "Measuring Impact of QoS on QoE in Mobile Web Services." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90334.
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With the development of mobile web services, it is important to know for a service provider how Quality of Service (QoS) is related with the Quality of Experience (QoE) for the mobile users. Any change in the QoS could be reflected on the QoE. However, good QoS does not always provide good QoE. Thus, a proper combination of QoS and QoE results in a good user experience. Good understanding of QoS and QoE is necessary in order to achieve that. In addition, identifying the proper relationship between network level QoS and user-end QoE is extremely challenging task which requires the highest level of accuracy. In order to understand the relation between QoS and QoE in a web service, an Apache server was setup with Google Map Web Service. In the server side, QoS parameters- delay, jitter and service unavailability were introduced for an experiment. In the user end, QoE was examined by doing experiment with different mobiles. In this test, 18 different conditions were experienced by the user who marked their QoE. This experiment was designed to collect data from the user to examine the user QoE and network level QoS. The results show that without server end Apache QoS module the service might be unavailable in high delay and jitter. However, with the Apache QoS module the service is available in high delay and jitter even though it takes longer time to respond. For better QoE, the delay and jitter should be as low as possible. Moreover, better QoE is experienced in better mobile design. Good mobile receiver and resolution make the QoE higher. Lower quality mobile design cannot ensure good service even though the network level QoS is good.
5
Cushnie, John. "QoS charging for Internet access networks : the wireless QoS gateway." Thesis, Lancaster University, 2003. http://eprints.lancs.ac.uk/12300/.
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WANG, XIAODONG. "QoS ISSUES AND QoS CONSTRAINED DESIGN OF WIRELESS SENSOR NETWORKS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1144634884.
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Jonsson, Björn. "Bluetooth QoS Scheduler." Thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93114.
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Bluetooth is a low cost, short-range radio technology that enables electronic devices to communicate wirelessly via ad-hoc networks. Different kinds of applications may run over these networks, some of these applications with particular Quality of Service (QoS) requirements. One such application could for instance be an Audio application which need data frames to be delivered at regular interval to work properly. The communication over Bluetooth links is totally controlled by one of the participating nodes. Since this node controls the traffic and thereby controls the QoS within the network its communicating behaviour is of great importance for maintaining QoS reservations. A central part in maintaining QoS reservations is the scheduler, which prioritises between different tasks to be done such as which device that is allowed to transmit next. There is no standardised way to implement the Bluetooth scheduler. However, a Bluetooth scheduler should be able to handle QoS reservations, maintain fairness among the participating nodes, and utilise the available bandwidth efficiently. Furthermore a key requirement in Bluetooth is simplicity, therefore a Bluetooth scheduling algorithm should be of low complexity. This master thesis presents a new patented solution for an intra-piconet scheduling algorithm that is capable of maintaining QoS reservation, while being fair and also meet the low complexity requirement. This algorithm is presented in detail in the thesis and has been implemented in an ns2- based Bluetooth simulator. Simulations in this simulator are presented that verifies the scheduling algorithms functionality.Bluetooth är en standard för trådlös ad-hoc kommunikation. Denna standard definierar i antalet noder begränsade nätverk (piconet) som kan kopplas samman till större nätverk (scatternet). Många olika typer av applikationer kan tänkas använda dessa nätverk, vissa av dessa med speciella krav på Quality of Service (QoS). Ett exempel så en dylik applikation är ljudöverföringar som kräver att data överförs med jämna mellanrum för att kunna fungera tillfredställande. Kommunikationen över ett Bluetooth-piconet kontrolleras helt av en av de deltagande enheterna. Eftersom denna enhet kontrollerar trafiken kontrollerar den också upprätthållandet av QoS reservationerna. En central del i detta upprätthållande är schemaläggaren, som är den del i en Bluetoothenhet som prioriterar mellan olika saker som ska utföras. Ett exempel på en sådan prioritering kan vara vilken enhet i nätverket som ska få kommunicera härnäst. Bluetooth standarden beskriver inte hur denna schemaläggare ska implementeras. Grundläggande krav på en Bluetooth schemaläggare är att den ska kunna hantera och upprätthålla QoS reservationer samtidigt som den delar den befintliga kapaciteten på ett rättvist och effektivt sätt mellan de deltagande enheterna. Vidare bör den ha en låg komplexitet eftersom enkelhet är ett krav på alla delar i ett Bluetoothsystem. Detta examensarbete presenterar en ny patenterad algoritm för schemaläggning i begränsade Bluetoothnät som är kapabel att upprätthålla QoS-reservationer, samtidigt som den distribuerar den tillgängliga kapaciteten på ett rättvist sätt. Algoritmen möter också upp till kravet på låg komplexitet. Rapporten innehåller vidare simuleringar av algoritmens funktion, dessa har utförts i en ns2-baserad Bluetooth miljö och verifierar algoritmens funktionalitet.
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Lahdenperä, J. (Juho). "QoS 4G-verkoissa." Bachelor's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201711153110.
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Tutkielma on kirjallisuuskatsaus, jossa perehdytään nykyään käytettäviin Quality of Service (QoS) ratkaisuihin 4G-verkoissa. QoS on tärkeä niin käyttäjän, kuin palvelun tarjoajan näkökulmasta. QoS:n avulla varmistetaan kullekin verkon käyttäjälle riittävä palvelun taso. QoS:n tarkastelua tarvitaan myös erilaisten järjestelmien suunnittelussa, että ymmärretään mitä järjestelmältä vaaditaan. 4G-verkon QoS parametrit on standardisoitu ja laitteiden QoS-mekanismit ovat globaaleilla televiestintämarkkinoilla tärkeä kilpailutekijäThis thesis is a literature review, that orients to the concept of modern day Quality of Service solutions in 4G-networks. QoS is important from the users’ as well as the service provider’s point of view. QoS provides a level of service for each network user and it is also required in system design to know what is required from the system. QoS parameters of 4G network are standardized and the QoS mechanisms are an important competitive factor in the global telecommunications market
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Ickin, Selim. "Quality of Experience on Smartphones : Network, Application, and Energy Perspectives." Doctoral thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00615.
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Smartphones have become crucial enablers for users to exploit online services such as learning, leisure, communicating, and socializing. The user-perceived quality of applications and services is an important factor to consider, in order to achieve lean resource management, to prevent user churn and revenue depletion of service or network providers. This is often studied within the scope of Quality of Experience (QoE), which has attracted researchers both in academia and industry. The objective of this thesis is to study the most important factors influencing QoE on smartphones and synthesize solutions for intervention. The temporal impairments during a real-time energy-hungry video streaming are studied. The aim is to quantify the influence of temporal impairments on the user-perceived video QoE at the network and application level together with energy measurements, and also to propose solutions to reduce smartphone energy consumption without degrading the user’s QoE on the smartphone for both user-interactive, e.g., video, and non-interactive cases. QoE measurements on smartphones are performed throughout in-the-wild user studies. A set of quantitative Quality of Experience (QoE) assessment tools are implemented and deployed for automatic data logging at the network- and application-level. Online momentary survey, Experience Sampling Method (ESM) software, and Day Reconstruction Method (DRM) along weekly face-to-face user interviews are employed. The subjective QoE is obtained through qualitative feedback including Mean Opinion Score (MOS) as well as in-situ indications of poor experiences by users. Additionally, energy measurements on smartphones are conducted in controlled-lab environment with the Monsoon device. The QoE of smartphone applications and services perceived by users depends on many factors including anomalies in the network, application, and also the energy consumption. At the network-level, high packet delay variation causes long video freezes that eventually impact negatively the end-user perceived quality. The freezes can be quantified as large time gaps in-between the displayed pictures during a video stream at the application-level. We show that the inter-picture time in cellular-based video stream can be represented via two-state exponential ON/OFF models. We show models representing the non-linear relationship between the QoE and the mean inter-picture time. It is shown that energy measurements help to reveal the temporal impairments in video stream enabling energy consumption as a QoE indicator. Next, energy waste and saving during temporal impairments are identified. Additionally, other video streaming use cases, e.g., “download first and watch later”, are studied and appropriate energy-saving download scheduling mechanisms are recommended. The possibility for decreasing energy consumption when the smartphone screen is OFF, while maintaining QoE, is revealed. We first show exponential models to represent user’s interaction with smartphone, then propose a NyxEnergySaver software, to control the cellular network interface in a personalized manner to save smartphone energy. According to our findings, more than 30% smartphone energy can be saved without impacting the user-perceived QoE.
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Senol, Sinan. "Qoc And Qos Bargaining For Message Scheduling In Networked Control Systems." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614396/index.pdf.
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Networked Control Systems (NCS) are distributed control systems where the
sensor signals to the controllers and the control data to the actuators are enclosed
in messages and sent over a communication network. On the one hand, the
design of an NCS requires ensuring the stability of the control system and
achieving system response that is as close as possible to that of an ideal system
which demands network resources. On the other hand, these resources are
limited and have to be allocated efficiently to accommodate for future system
extensions as well as applications other than control purpose. Furthermore the
NCS design parameters for the control system messages and the message
transmission over the network are interdependent. In this thesis, we propose
&ldquoIntegrated NCS Design (INtERCEDE: Integrated NEtwoRked Control systEm DEsign)&rdquo
a novel algorithmic approach for the design of NCS which ensures the stability of the control system, brings system response to that of an ideal system v as close as desired and conserves network bandwidth at the same time. The core of INtERCEDE is a bargaining game approach which iteratively calculates the message parameters and network service parameters. Our experimental results demonstrate the operation of INtERCEDE and how it computes the optimal design parameters for the example NCS.
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Ksentini, Adlen. "Building the bridges between QoS and QoE for network control mechanisms." Habilitation à diriger des recherches, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00913872.
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Cette dernière décennie a connu une prolifération des réseaux d'accès sans fil, dominée par les réseaux locaux sans fil (ou Wireless Local Area Network - WLAN), les réseaux cellulaires 3GPP de troisième (3G) et quatrième génération (4G) et en moindre mesure les réseaux Digital Video Broadcast (DVB) pour la télévision numérique. Conjugué à l'apparition des téléphones intelligents (Smartphone) et des tablettes, les réseaux sans fil ont changé la façon dont les utilisateurs consomment les applications Internet, où on constate que l'accès aux plateformes vidéo (Youtube, vidéo à la demande, Télé sur IP) et aux réseaux sociaux à partir des réseaux sans fil et mobiles a explosé. L'accès massif à ces applications par le biais des réseaux sans fil introduit de nouveaux verrous, liés principalement à l'augmentation du trafic et l'aspect temps réel de certaines applications, où un certain niveau de Qualité de Service (QdS)/Qualité d'Expérience (QdE) doit être assuré. Par conséquent, un certain nombre de défis se posent : (i) aux opérateurs des réseaux sans fil et mobiles, pour lesquels il est nécessaire d'avoir des nouveaux mécanismes et protocoles réseaux pour éviter la congestion et garantir la QdS/QdE aux utilisateurs ; (ii) aux fournisseurs de contenus (service provider) qui doivent s'adapter au contexte de l'utilisateur (bande passante, terminal utilisé, résolution, etc.) lors de la création de contenus audiovisuels (audio et vidéo). Afin d'adresser les problématiques citées dans la section précédente, l'originalité de nos contributions se situe dans la proposition de protocoles et mécanismes de contrôle de réseau dits dynamiques ou adaptatifs. L'approche dynamique permet de s'adapter : (i) aux changements de l'état du réseau (niveau de charge/contention) ; (ii) aux changements de l'état du canal sans fil (dégradation/amélioration du canal physique) ; (iii) à l'augmentation ou la réduction du trafic d'une application ; (iv) à la dégradation de la qualité de service/expérience de l'utilisateur. De ce fait, nos travaux ont généralement considéré le réseau (ou l'application réseau) ainsi que la fonction ou le mécanisme à contrôler comme un système en boucle fermée, dont le but est de modifier (contrôler) l'état d'entrée (accepter ou refuser un nouveau flux, augmenter la durée de mise en veille d'une station, maitriser la congestion, etc.) du système et mesurer les paramètres en sortie (délais, QdE) pour les prendre en compte lors des prochaines décisions du mécanisme de contrôle. Ces mesures se font soit au niveau du réseau, terminal ou application. Nos contributions sont classées suivant la nature de la mesure utilisée. Une partie de nos travaux utilise des mesures centrées QdS/réseau (tel que l'intensité du trafic, la taille de la file d'attente, débit de la station, délai applicatif), et l'autre partie est centrée sur l'utilisateur (ou human-centric) à travers la mesure de la qualité d'expérience perçue par l'utilisateur.
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Fujikawa, Kenji. "A Study on QoS Guarantee, QoS Routing and Multicast on the Internet." 京都大学 (Kyoto University), 2000. http://hdl.handle.net/2433/151472.
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Tian, Min [Verfasser]. "QoS integration in Web services with the WS-QoS framework / Min Tian." Berlin : Freie Universität Berlin, 2005. http://d-nb.info/1021667587/34.
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Tamura, Gabriel. "QoS-CARE : a reliable system for preserving QoS contracts through dynamic reconfiguration." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10031/document.
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Le principal défi de cette thèse est de préserver de façon fiable la qualité de service (QoS) définie par contrats dans des systèmes logiciels à base de composants, ceci dans des conditions changeantes d'exécution du système. En réponse à ce défi, nous présentons deux contributions. La première est un modèle pour les applications logicielles à base de composants avec contrats de qualité de service et règles de reconfiguration définies par des graphes attribués typés. Ainsi, nous utilisons des modèles formels à l'exécution pour reconfigurer de manière fiable des applications logicielles de façon à préserver les contrats de QoS. Plus précisément, nous montrons la faisabilité d'exploiter des patrons de conception à l'exécution dans des boucles de reconfiguration tout en garantissant les niveaux de QoS attendues. Nous mettons en œuvre ce modèle formel par le biais d'une architecture à base de composants qui peut être utilisée comme une couche supplémentaire de la plateforme SCA, ceci afin de préserver les contrats de QoS.La seconde contribution est la caractérisation des propriétés d'adaptation pour évaluer les systèmes logiciels auto-adaptatifs de manière standardisée et comparable. De par leur nature, les mécanismes d'adaptation des systèmes logiciels auto-adaptatifs sont essentiellement des boucles de rétroaction telles que définies par la théorie du contrôle. Ainsi, pour les évaluer, il est nécessaire de ré-interpréter ces proprétés dans le domaine du logiciel. Nous définissons la fiabilité de la réalisation de notre modèle formel en termes de sous-ensemble des propriétés d'adaptation caractérisées, et nous montrons que ces propriétés sont garanties dans cette réalisationThe main challenge of this Thesis is to reliably preserve quality of service (QoS) contracts in component-based software systems under changing conditions of system execution. In response to this challenge, the presented contribution is twofold. The first is a model for component-based software applications, QoS contracts and reconfiguration rules as typed attributed graphs, and the definition of QoS-contracts semantics as state machines in which transitions are performed as software reconfigurations. Thus, we effectively use (formal) models at runtime to reliably reconfigure software applications for preserving its QoS contracts. More specifically, we show the feasibility of exploiting design patterns at runtime in reconfiguration loops to fulfill expected QoS levels associated to specific context conditions. We realize this formal model through a component-based architecture and implementation that can be used as an additional layer of SCA middleware stacks to preserve the QoS contracts of executed applications.The second contribution is the characterization of adaptation properties to evaluate self-adaptive software systems in a standardized and comparable way. By its own nature, the adaptation mechanisms of self-adaptive software systems are essentially feedback loops as defined in control theory. Thus, it results reasonable to evaluate them using the standard properties used to evaluate feedback loops, re-interpreting these properties for the software domain. We define the relibility of our formal model realization in terms of a subset of the characterized adaptation properties, and we show that these properties are guaranteed in this realization
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Horbach, Jan. "Dynamische Bandbreitenbeschränkung mit QoS." Master's thesis, Universitätsbibliothek Chemnitz, 2001. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200101001.
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Diese Diplomarbeit beschäftigt sich mit der
"schleichenden Abschaltung" begrenzter
Netzzugänge bei Überschreitung eines vorgegebenen
Datenvolumens und der Anwendung dieser Technologie
im Chemnitzer Studentennetz. Nutzer, die bestimmte
Transfervolumina überschreiten, werden
schrittweise einer immer schlechter bewerteten
Verkehrsklasse zugeordnet, wo ihnen weniger
Bandbreite zur Verfügung steht. Dazu werden die
Möglichkeiten, die der Linux-Kern hinsichtlich
Quality of Service bietet, genutzt.
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Roumani, Ali Mohamad. "QoS-based multicast routing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0034/MQ52943.pdf.
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Grift, Werner. "Visualizing Qos in networks." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/17356.
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Thesis (MSc)--University of Stellenbosch, 2006.ENGLISH ABSTRACT: Network simulations generate large volumes of data. This thesis presents an animated visualization system that utilizes the latest affordable Computer Graphics (CG) hardware to simplify the task of visualizing and analyzing these large volumes of data. The use of modern CG hardware allows us to create an interactive system which allows the user to interact with the data sets and extract the relevant data in real time. We also present an alternate approach to the network layout problem, using Self Organizing Maps to find an aesthetic layout for a network which is fundamental to a successful network visualization. We finally discuss the design and implementation of such an network visualization tool.
AFRIKAANSE OPSOMMING: Netwerk simulasies genereer groot volumes data. Hierdie tesis stel voor ’n geanimeerde visualiseringwat gebruik maak van die nuutste bekostigbare rekenaar grafika hardeware om die visualisering van groot volumes data te vergemaklik. Die gebruik van moderne rekenaar grafika hardeware stel ons in staat om sagteware te skep wat n gebruiker in staat stel om met die data te werk. Ons stel voor ’n alternatiewe benadering om die netwerk se uitleg daar te stel, met die hulp van tegnieke wat gebruik word in die studie van neurale netwerke. Ons bespreek dan die ontwerp en implementering van so ’n netwerk visualisering program.
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Kalina, Tomáš. "QoS v síti VŠE." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-164040.
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The diploma thesis is focused on analysis and deployment of Quality of Services (QoS) in a computer network of The University of Economics in Prague (VŠE). The thesis describes the main QoS technologies focusing on technology Diffserv and its deployment with using available network devices in computer network of VŠE. In thesis the needs of network services and protocols for quality of services with division into different classes of services according to priority are discussed. The thesis explains the benefits and drawbacks of deploying QoS in the environment of VŠE with regard to wired and wireless network. In the practical part recommendations are applied to the production network and subsequently the benefits of modification are evaluated.
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Horbach, Jan. "Dynamische Bandbreitenbeschränkung mit QoS." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10047781.
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Tondello, Gustavo Fortes. "Especificação semântica de QoS." Florianópolis, SC, 2008. http://repositorio.ufsc.br/xmlui/handle/123456789/91511.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da ComputaçãoMade available in DSpace on 2012-10-23T23:47:03Z (GMT). No. of bitstreams: 1 259451.pdf: 1464324 bytes, checksum: f73443a4cdf02c0e6aa0420528c89c98 (MD5)
Este trabalho apresenta a ontologia QoS-MO que permite a especificação de características e requisitos de QoS para Web Services Semânticos ou Componentes de Software e pode ser facilmente utilizada para estender a OWL-S ou outras ontologias de descrição funcional de Componentes. As especificações de QoS modeladas a partir da ontologia QoS-MO podem ser utilizadas no projeto, desenvolvimento, publicação e descoberta de Web Services ou Componentes de Software. Um mecanismo de busca semântica de Web Services ou Componentes de Software foi especificado, voltado para a descoberta de Componentes que atendam a um conjunto definido de restrições de QoS, utilizando a ontologia QoS-MO e a linguagem de consulta SPARQL. Um protótipo deste mecanismo foi desenvolvido, contando tanto com uma interface de programação como uma interface Web. Os testes realizados demonstraram que o mecanismo proposto é viável e apresenta um desempenho aceitável e que a ontologia definida é capaz de expressar características de QoS complexas. A comparação com mecanismos de descoberta de Web Services de propostas similares demonstrou que a abordagem QoS-MO é mais simples e eficiente, pois não depende de nenhum algoritmo complexo para sua execução, apenas de um mecanismo de inferência simples e da linguagem SPARQL.
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Bumbál, Miroslav. "QoS v IP síti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217998.
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Master 's thesis deals about computer networks, which constitutes a global communication structure and play a very important role in today's society. The rapid development of Internet, the emergence of new multimedia applications and their increasing use of calls to the efficient functioning of the creation of such governance mechanisms of transmission, which are able to secure the required parameters. The thesis deals about the issue of quality of service (QoS) in IP networks. It presents the basic characteristics and requirements of these networks for the transmission of sensitive data by the quality of services, deals with the QoS definition, and describes the essential parameters to be followed to achieve the required quality of service in practical deployment. In addition, lists the various principles and options to ensure QoS in computer networks. Generally, it represents the Cisco 1841 router features and options to ensure quality of service in the network based on these routers. Practical thesis part provides two types of model IP networks, which were designed in order to verify the impact of service quality in real practice. Of the known methods to ensure QoS, which include a mechanism of Integrated services, Differentiated services, it focus its content about the Differentiated Services and the implementation of these in proposed network model. The last part of the work presents the results obtained by the impact of quality of service for the applications and their assessment.
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Kavan, Radovan. "QoS v systému UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218026.
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This thesis treats of QoS (Quality of Service) in UMTS system. The term quality of service is frequently used, recently, however not only in computer networks, but also more and more in mobile networks also. Present system of 2nd generation (2G) GSM enables only limited exploitation of QoS function. System UMTS is a system of 3rd generation (3G) already and contains quality of service in greater measure which is ensured with number of algorithms and functions. Individual QoS functions enable effective utilization of radio interface, support maintenance of planned coverage and offer high spectral efficiency. Functions that cater to quality of service are called RRM functions (Radio Resource Management). There exist five basic functions in UMTS system that are Admission control (AC), Power control (PC), Load control (LC), Handover control (HC) and Packet scheduler (PS). These functions are responsible for control of network access, control of power, control of network load, control of handover and packet (bit rate) scheduling. Last three functions are usually collectively designated as Congestion control, control of network overload. UMTS layer model, differentiation of services, traffic classes and 3GPP concept are also discussed. In thesis the attention is piad to Admission control algorithm – control of network access – in the uplink direction and to different ways of load (in the cell) modeling. Individual approaches are simulated in MATLAB. A possibility of using algorithm in the real system is discussed in conclusion.
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MEDEIROS, Iago Lins de. "QoE and QoS-aware handover for vídeo transmission in heterogeneous vehicular networks." Universidade Federal do Pará, 2018. http://repositorio.ufpa.br/jspui/handle/2011/10043.
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Redes Veiculares (VANETs) oferecem uma ampla gama de serviços multimídia que vão desde alertas de segurança a vídeos de entretenimento e publicidade. Neste contexto, os usuários podem acessar o conteúdo através da comunicação Veículo-para-Infraestrutura (V2I), que pode considerar diferentes redes sem fio, tais como LTE, Wi-Fi, etc. No entanto, transmissão de vídeo em uma VANET com qualidade de Experiência (QoE) e Qualidade de Serviço (QoS) é uma tarefa desafiadora, devido à alta mobilidade do veículo que causa falhas de comunicação com a infraestrutura. Para mitigar tais fatores, esta dissertação de mestrado apresenta um algoritmo de handover que considera QoE, QoS e qualidade do canal em redes heterogêneas, chamado de handover ciente de Qualidade de Serviço, Experiência e Rádio (SER). O algoritmo proposto considera o Analytic Hierarchy Process (AHP) para ajustar o grau de importância de cada critério na escolha da esta¸cão rádio base apropriada que o nó móvel deve se conectar, permitindo uma decisão de handover mais eficiente para transmissão de vídeo com suporte a QoE. Resultados de simulação constatam que o handover SER entregou vídeos com QoE 15% melhor comparado aos algoritmos encontrados na literatura.
Vehicle Ad Hoc Networks (VANETs) offer a wide range of multimedia services ranging from safety and traffic warnings to entertainment and advertising videos. In this context, users can access content through vehicle-to-infrastructure (V2I) communication, which may consider different wireless networks, such as, LTE, Wi-Fi, etc. However, video streaming at a VANET with Quality of Experience (QoE) and Quality of Service (QoS) is a challenging task, due to the high vehicle’s mobility that causes communication failure with the infrastructure. To mitigate such factors, this master’s dissertation presents a handover algorithm that considers QoE, Quality of Service (QoS) and channel quality in heterogeneous networks, known as handover aware of Quality of Service, Experience and Radio (SER). The proposed algorithm considers the Analytic Hierarchy Process (AHP) to adjust the degree of importance of each criteria in choosing the appropriate radio base station that the mobile node must connect to, allowing a more efficient handover decision for video transmission with QoE support. Simulation results show that SER handover delivered videos with QoE 15 % better compared to the algorithms found in the literature.
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Batista, Caio Sergio de Vasconcelos. "Um monitor de metadados de QoS e QoC para plataformas de middleware." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17959.
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Previous issue date: 2014-02-06Context-aware applications are typically dynamic and use services provided by several sources, with different quality levels. Context information qualities are expressed in terms of Quality of Context (QoC) metadata, such as precision, correctness, refreshment, and resolution. On the other hand, service qualities are expressed via Quality of Services (QoS) metadata such as response time, availability and error rate. In order to assure that an application is using services and context information that meet its requirements, it is essential to continuously monitor the metadata. For this purpose, it is needed a QoS and QoC monitoring mechanism that meet the following requirements: (i) to support measurement and monitoring of QoS and QoC metadata; (ii) to support synchronous and asynchronous operation, thus enabling the application to periodically gather the monitored metadata and also to be asynchronously notified whenever a given metadata becomes available; (iii) to use ontologies to represent information in order to avoid ambiguous interpretation. This work presents QoMonitor, a module for QoS and QoC metadata monitoring that meets the abovementioned requirement. The architecture and implementation of QoMonitor are discussed. To support asynchronous communication QoMonitor uses two protocols: JMS and Light-PubSubHubbub. In order to illustrate QoMonitor in the development of ubiquitous application it was integrated to OpenCOPI (Open COntext Platform Integration), a Middleware platform that integrates several context provision middleware. To validate QoMonitor we used two applications as proofof- concept: an oil and gas monitoring application and a healthcare application. This work also presents a validation of QoMonitor in terms of performance both in synchronous and asynchronous requests
Aplica??es cientes de contexto s?o tipicamente din?micas e caracterizam-se por utilizar servi?os providos por v?rias fontes, com diferentes n?veis de qualidade. A qualidade de uma informa??o de contexto ? expressa atrav?s dos metadados de Qualidade de Contexto (QoC), como precis?o, corretude, atualidade, resolu??o. Por sua vez, a qualidade de um servi?o ? expressa atrav?s dos metadados de Qualidade de Servi?o (QoS), como tempo de resposta, taxa de erro, disponibilidade e tempo m?dio entre falhas. Para garantir que uma aplica??o est? utilizando servi?os e informa??es de contexto com n?veis de QoS e QoC que satisfa?am seus requisitos, ? essencial que elas estejam continuamente cientes desses metadados. Para tanto, ? necess?rio utilizar um mecanismo de monitoramento de QoS e QoC que atenda aos seguinte requisitos: (i) forne?a suporte a aferi??o e monitoramento de metadados de QoS e QoC; (ii) opere de forma s?ncrona como tamb?m de forma ass?ncrona, permitindo que a aplica??o especifique uma condi??o e o monitor informe quando ocorre algum evento que satisfa?a a condi??o;; (iii) use ontologias para representa??o da informa??o de forma a evitar interpreta??es amb?guas. Este trabalho prop?e o QoMonitor, um m?dulo para monitoramento de metadados de QoS e QoC que atende a tais requisitos. A arquitetura e a implementa??o do QoMonitor s?o discutidos. Para requisi??es ass?ncrona o QoMonitor usa dois protocolos: JMS e Light-PubSubHubbub. De forma a ilustrar o uso do QoMonitor no contexto do desenvolvimento de aplica??es ub?quas ele foi integrado ao OpenCOPI (Open COntext Platform Integration), uma plataforma integradora de diferentes Middleware de provis?o de contexto que fornecem servi?os e seus respectivos metadados. Para validar o uso do QoMonitor s?o utilizados duas aplica??es como provas de conceito que exploram as capacidades do monitor: uma aplica??o da ind?stria de petr?leo e g?s, e uma aplica??o de healthcare. Esse trabalho tamb?m apresenta uma avalia??o do QoMonitor em termos de desempenho tanto no contexto de requisi??es s?ncronas como ass?ncronas
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Odarchenko, R. S., and T. V. Dyka. "Research of applications for QOE and QOS analysis in cellular radio networks." Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/50644.
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1. The Alladin Nettest on computer. URL: https://appnapc.com/535471/ (Last accessed:
01.03.2021).
2. Quality of Experience (QoE) powered by EcoSGE. URL: https://www.rdp.ru/products/service-gateway-engine/qoe (Last accessed: 01.03.2021).In light of these trends, cellular network operators are becoming more and more interested in understanding how to scale their access networks and how to manage their customers' traffic to capture as many new customers as possible. In this scenario, the concept of experience quality (QoE) can become one of the main paradigms of quality management in cellular networks. Closely related to the subjective perception of the end user, QoE provides a broader understanding of the factors that affect the efficiency of systems, complementing traditional technology-oriented concepts such as quality of service (QoS).
У світлі цих тенденцій оператори стільникової мережі стають дедалі більше зацікавленими у розумінні того, як масштабувати свої мережі доступу та як управляти трафіком своїх клієнтів, щоб охопити якомога більше нових клієнтів. У цьому сценарії концепція якості досвіду (QoE) може стати однією з головних парадигм управління якістю в стільникових мережах. Тісно пов'язане із суб'єктивним сприйняттям кінцевого споживача, QoE забезпечує більш широке розуміння факторів, що впливають на ефективність систем, доповнюючи традиційні технологічно орієнтовані концепції, такі як якість обслуговування (QoS).
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Madhi, Kristi. "Impact of QoS and contextual parameters on QoE in a videoconferencing application." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-204918.
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This project will be based in an objective and as well as subjective study related to Quality of Experience in a video conference application, appear.in. Indeed the study puts emphasis on finding possible correlations between Quality of Service parameters, that in the study are represented by some of the most meaningful network parameters, and contextual parameters with Quality of Experience. To achieve this the study was based in two different scenarios using two test environments. One is based on having an all free test and the other conducted in a created test-bad for monitoring and altering network parameters to see how user respond to the changes. Both scenarios were accompanied by a survey that provided useful information about the subjective perception of different individuals that took part in the testing phase.The project is divided in two phases where we set up the required environments for the test and then we process results to find correlation between the above mentioned parameters.In the end of the project all the results and the conclusions are presented providing a clearer view for what was done. The project itself might represent a good foundation to be used in the future for other studies related to video conferencing application.
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Ghinea, Gheorghita. "Quality of perception : an essential facet of multimedia communications." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312428.
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ALBUQUERQUE, JÚNIOR Edivaldo Cavalcante de. "Wi-Flow: uma arquitetura baseada em SDN para o gerenciamento e mobilidade em redes Wi-Fi com suporte à autenticação 802.1x." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18587.
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As redes corporativas têm evoluído para um ambiente heterogêneo (rede sem fio e cabeada). Estas redes consideram a autenticação do usuário um elemento primordial para garantir níveis adequados de segurança no acesso aos serviços estratégicos da organização. Nas instituições de ensino e pesquisa, o sistema federado baseado na autenticação 802.1x chamado Eduroam (Education Roaming) permite que estudantes e pesquisadores obtenham conectividade sem fio utilizando as mesmas credenciais de suas instituições em qualquer lugar do mundo com suporte a este sistema. Contudo, a qualidade de serviço (QoS) percebida pelo usuário pode ser degradada quando da necessidade de mudança do ponto de acesso sem fio (handover) devido à mobilidade e necessidade de reautenticação de uma sessão em andamento. Apesar das inúmeras soluções existentes na literatura para o gerenciamento de mobilidade, o suporte à autenticação do usuário no processo de handover é um aspecto negligenciado. Esta dissertação propõe um arcabouço para o gerenciamento integrado de redes cabeadas e sem fio baseado em software de código aberto e de baixo custo. A proposta visa tornar o gerenciamento mais simples e centralizado utilizando o paradigma de redes definidas por software (SDN – Software Defined Networking) através do protocolo OpenFlow (OF). Via interface Web é possível obter informações da rede, gerenciar fluxos e controladores OF, criar slices de rede e aplicar políticas de QoS. No contexto do gerenciamento de mobilidade, a proposta implementa e avalia uma estratégia de cache de autenticação que otimiza a qualidade de experiência (QoE) durante o processo de handover e ambiente com autenticação 802.1x/Eduroam. A avaliação foi realizada num ambiente de experimentação e a proposta obteve como resultados os seguintes ganhos: 15,8% na vazão, 25% no atraso médio e 20,5% no PSNR em relação ao cenário de não utilização da proposta de cache de autenticação. Os resultados obtidos demonstram a aplicabilidade da proposta no gerenciamento mobilidade seguro, bem como sua eficácia no suporte aos requisitos de QoS/QoE para sessões de tráfego de vídeo de usuários móveis.
Corporate networks have evolved into a heterogeneous environment (wired and wireless networks). These networks consider user authentication as a key element to ensure adequate levels of security access to the organization's strategic services. In educational and research institutions, the federated system based on 802.1x authentication called Eduroam (Education Roaming) allows students and researchers to gain wireless connectivity using the same credentials of their institutions anywhere in the world that supports this system. However, the quality of service (QoS) perceived by the user can be degraded when they need to change the wireless access point (handover) due to mobility and re-authenticate a session in progress. Despite numerous existing solutions in the literature for mobility management, support for user authentication in the handover process is a neglected aspect. This dissertation proposes a framework for the integrated management of wired and wireless networks based on low cost and open source software. The proposal aims to make simpler and centralized management using the SDN (Software Defined Networking) paradigm via OpenFlow protocol (OF). Through web interface is possible to obtain information from the network, manage flows and OF controllers, create network slices, and apply QoS policies. In the mobility management context, this proposal implements and evaluates a strategy that improves the quality of experience (QoE) environment with 802.1x authentication / Eduroam. In the evaluated experimental environments, the proposed technique achieved gains up to 15.8% on throughput, 25% on average delay and 20.5% on PSNR in comparison to the baseline scenario without authentication cache. Thus, the obtained results demonstrate the applicability of the integrated network management, as well as its effectiveness in supporting of QoS / QoE requirements for video traffic sessions of the mobile users.
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Bakhsh, Helen Jameel H. "ATL-QoS : an adaptive trust-aware location-based framework for achieving QoS in MANETs." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/atlqos-an-adaptive-trustaware-locationbased-framework-for-achieving-qos-in-manets(d0c5f89e-5576-4a91-a601-aa4aca60e15a).html.
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Mobile ad hoc networks (MANETs) have gained increasing attention from industry for their potential applications. MANETs allow devices to communicate in areas with no pre-existing communication infrastructure. In MANETs, node mobility leads to dynamic changes in network topologies and fluctuations in network available bandwidth. The lack of infrastructural support means that communication nodes need to collaborate among themselves functioning as routers (intermediate nodes) for other nodes. This places additional processing and communication loads onto the communication nodes and opens up doors to more active attacks by intermediate nodes. It is also worth noting that mobile nodes are typically battery powered, and they are more restrictive in terms of storage space and processing capabilities than their wired counterpart. These MANET features indicate that achieving QoS in MANETs should be done in the most cost-effective manner. In this thesis, a novel Adaptive Trust-aware Location-based (ATL-QoS) framework is proposed. The ATL-QoS framework can harvest fluctuating available bandwidth in the underlying network to deliver high priority traffic in various network conditions. The novelty of the framework lies in that it uses single path and multiple path deliveries and packet duplication over multiple path, in an adaptive manner, in an attempt to increase high priority traffic delivery with minimum bandwidth overhead costs. The framework handles low and high priority traffic in a differential manner. To implement these ideas, two novel ATL-QoS components are designed: (1) a Trust-Aware Dynamic Location-based (improved version) (TADLV2) multiple path discovery protocol and (2) a path Selection, traffic Allocation, and path Verification (SAV) solution. The TADLV2 protocol is designed to discover multiple path between a pair of communication nodes with minimum bandwidth overheads, we first designed TADL protocol and then an improved version of TADL, TADLV2. The SAV solution is designed to increase high priority traffic delivery success. These ATL-QoS framework ideas are implemented and evaluated using the NS-2 simulation and compared against the most relevant protocol in the literature. The simulation study shows that ATL-QoS outperforms the relevant protocol in terms of reducing routing overheads and increasing packet delivery ratios. These enhancements making ATL-QoS more effective in providing QoS.
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SILVA, JUNIOR Reinaldo Boulhosa Ramos da. "Gerenciamento de mobilidade transparente com suporte integrado a QoS/QoE em redes heterogêneas." Universidade Federal do Pará, 2012. http://repositorio.ufpa.br/jspui/handle/2011/3000.
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Os avanços nas tecnologias de comunicação sem fio, a demanda por novas aplicações multimídia em tempo real, com requisitos de Qualidade de Serviço (QoS) e Qualidade de Experiência (QoE), e a proliferação de equipamentos móveis, originam o surgimento de soluções que permitem mobilidades horizontais e verticais em redes heterogêneas, de modo transparente. Esses dispositivos móveis apresentam múltiplas interfaces sem fio, onde os usuários se conectam para realizar tarefas e serviços variados no seu dia a dia, mediante a tecnologia de redes diferentes, proporcionando um cenário heterogêneo com diversas oportunidades de conectividade para os usuários móveis. Visando solucionar o problema de várias conexões, feitas por usuários móveis, em uma mesma rede Wi-Fi (Wireless Fidelity) e/ou WiMAX (Worldwide Interoperability for Microwave Access) com diferentes serviços executados, porém, utilizando incorretamente a rede, esta dissertação propõe uma técnica hierárquica de decisão de mobilidade transparente, baseada em uma função de custo, no padrão IEEE 802.21 e no mapeamento de classes de serviço para garantir QoS/QoE para usuários em períodos de mobilidade chamada de MIH2Q, onde essa política informa a melhor rede para ser utilizada, de acordo com o serviço utilizado pelo usuário móvel. A avaliação do impacto e os benefícios da proposta são feitas através de simulação no NS-2 (Network Simulator - version 2) e no evalvid, utilizando métricas de QoS e QoE para verificação dos resultados.
Advances in wireless communications technology, and the demands for new real-time multimedia applications that meet the Quality of Service (QoS) and Quality of Experience (QoE) requirements, together with the proliferation of mobile equipment, have given rise to new solutions that allow horizontal and vertical mobility in transparent heterogeneous networks. These mobile devices have multiple wireless interfaces where the users are connected so that they can carry out several tasks and services on a daily basis through the technology of different networks that allow a heterogeneous scenario with a wide range of connectivity opportunities for the mobile users. This dissertation sets out a fast decision hierarchical technique for transparent mobility based on cost function in the IEEE 802.21 Standard and class-of-service mapping, to ensure QoS/QoE for the users in periods of mobility called M1H2Q, during which this policy gives information about the best network that can be used for the service employed by the mobile user. It seeks to overcome the problem of having several connections being made by mobile users on the same Wireless Fidelity (wi-fi) network and/or WiMAX (Worldwide Interoperability for Microwave Access) with different services being executed, even though the network is not used correctly. The effects and benefits of the scheme were assessed through NS-2 simulation (Network Simulator- Version 2) and Evalvid, and the QoS and QoE metrics were used to check the results.
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Hao, Fang. "Scalability techniques in QoS networks." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/9175.
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Walsh, S. M. "Packet scheduling for wireless QOS." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487465.
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Since their arrival in the late 90's wireless packet schedulers have sought to seamlessly re-apply the concepts of fair queuing (FQ) algorithms (traditionally employed in wire-mediated communications) to provide fairness, throughput and delay gutUlUltees to individual sessions in the wireless environment. What has militated against a smooth transition in this regard is the presence of unpredictable bursty location-dependent channel errors due to fading on the wireless channel. The approach generally employed by wireless schedulers for minimizing the effects of channel errors is to use a compensation policy. Compensation has traditionally been applied in two -ways: (a) penalizing sessions that have utilized extra bandwidth gained from the loss ofanother session and (b) reserving a fraction ofthe system bandwidth. This dissertation presents a novel scheduling approach that employs multiple sources of compensation so that an emphasis is placed on allowing sessions to recover as quickly as possible from channel errors, while at the same time preserving the guarantees ofother sessions in the system. Two crucial factors are identified that influence how wireless packet scheduling should be performed namely the channel bandwidth and the traffic variation. In order to better understand the dynamics ofthese two driving forces, this dissertation quantifies and analyzes the behavior of each ofthese parameters in typical real-world worst-case scenarios. Through investigating the nature ofthese two aspects ofthe network, a number of conclusions are drawn on how certain wireless scheduling procedures should be implemented. In particular the recording of lost service and the application of compensation are significantly affected by the nature of these two system attributes. It is shown that wireless scheduling algorithms must incorporate far more system knowledge than what was traditionally required for the wired environment. This research proposes a novel traffic profile and priority based wireless fair queuing (TPP-WFQ) scheduling algorithm that is heavily reliant on system functions that perform; bandwidth management, weight adjustment, link adaptation, queue management, traffic classification and traffic monitoring. Several novel attributes are introduced with the TPP-WFQ algorithm, these include: (i) A novel lag/lead calculation model that makes use of knowledge of the traffic profile to accurately measure the amount of service lost and gained for different sessions when an error occurs. (ii) A novel compensation approach that adopts five sources ofcompensation. This allows for a fast recovery time which is the fundamental attribute that has motivated extensive research in the field of wireless scheduling. (iii) A classbased weight adjustment function that manages the weights for all sessions in the system when partial errors occur on channels due to link adaptation. (iv) A priority-based compensation approach that ensures that compensatory resources are prioritized according to the class oftraffic being compensated. This ensures that delay-sensitive sessions recover more quickly than delay-tolerant ones. Detailed simulations incorporating multiple worst-case scenarios illustrate that these areas of novelty enable TPP-WFQ to perform significantly better than selected high ranking schedulers presented in the literature at providing strong QoS to sessions in an error prone environment. In particular, we demonstrate that TPP-WFQ allows delay-sensitive real-time sessions to becom~ more resilient to poor channel conditions.
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Islam, Mohammad Kamrul. "QoS In Parallel Job Scheduling." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1218566682.
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Adepu, Sagarika. "Qos Aware Service Oriented Architecture." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc500032/.
Full textAbstract:
Service-oriented architecture enables web services to operate in a loosely-coupled setting and provides an environment for dynamic discovery and use of services over a network using standards such as WSDL, SOAP, and UDDI. Web service has both functional and non-functional characteristics. This thesis work proposes to add QoS descriptions (non-functional properties) to WSDL and compose various services to form a business process. This composition of web services also considers QoS properties along with functional properties and the composed services can again be published as a new Web Service and can be part of any other composition using Composed WSDL.
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Martins, José Carlos Ferreira da Silva. "QoS em servidores HTTP Apache." Master's thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/17549.
Full textAbstract:
Os serviços baseados na Internet têm registado um crescimento contínuo e acelerado nos
últimos anos, dependendo o seu sucesso, em larga medida, da qualidade de serviço prestada.
A sociedade moderna tornou-se fortemente dependente da Internet e dos vários serviços nela
disponibilizados.
Nesta dissertação é abordado o problema da qualidade de serviço em servidores HTTP, com
particular ênfase no servidor HTTP Apache. Neste trabalho, é definido e implementado
um sistema original de controlo em cadeia fechada de QoS, baseado nas metodologias da
teoria de controlo, demonstrando-se a sua robustez, estabilidade e capacidade para gerir
os recursos de forma dinâmica. Por fim, é comprovada a capacidade do sistema realizar a
diferenciação de serviço (DiffServ) entre duas classes de sítios: Premium e Outros. Esta
qualidade é comprovada para os objetivos erro nulo, rejeição de perturbações e seguimento
de referência; Abstract:
QoS for Apache HTTP server
Internet-based services have registered a continuous and rapid growth in recent years, depending
their success to a large extent on the provided quality of service. Modern society
has become heavily dependent on the Internet and the various services it provides.
This thesis addresses the issue of quality of service in HTTP servers, with particular emphasis
on the Apache HTTP server. In this work, a closed-loop system with QoS, based on
control theory methodologies, is defined and implemented. The proposed system robustness,
stability and ability to manage resources dynamically is shown. Finally, it is confirmed
the system’s ability to provide differentiated services (DiffServ) between two classes of sites:
Premium and Others. This quality is proven to the objectives regulatory control, disturbance
rejection and time-varying reference.
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Korkmaz, Turgay. "QoS routing in packet networks." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/289740.
Full textAbstract:
The current best-effort service of the Internet is not sufficient to meet the demands of emerging real-time network applications (e.g., video conferencing, Internet telephony). This has motivated the development of new networking technologies (e.g., Intserv, Diffserv, MPLS) that are geared towards providing quality-of-service (QoS) guarantees (e.g., bandwidth, delay, fitter, reliability) to prospective flows. Various aspects of these technologies are being extensively investigated in the research community. In this dissertation, we focus on the routing aspect, with the objective of providing scalable and computationally efficient solutions. The QoS routing problem involves two tasks: (a) capturing and disseminating the state information of the underlying network; and (b) using this information to compute resource-efficient constrained paths. In the presence of multiple constraints (QoS link parameters), these two tasks become notoriously challenging. We investigate several key issues in QoS routing and discuss how to integrate the provided solutions into evolving state-dependent and hierarchical routing protocols (e.g., PNNI and QoS-extended OSPF). First, we develop a hybrid mechanism based on both flooding and tree-based broadcasting for reliable and efficient dissemination of dynamic link-state parameters, such as bandwidth. Second, we present a scalable, source oriented state aggregation methodology for hierarchical networks. Third, we introduce several heuristics and approximation algorithms for path selection under multiple QoS constraints. Fourth, we consider the path selection problem under inaccurate (probabilistically modeled) state information, and provide a heuristic for a special yet important case of this problem, namely, routing under bandwidth and delay constraints. Finally, we evaluate the performance of the proposed methods through simulations.
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Adámek, David. "Implementace QoS v přístupové síti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217611.
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This diploma thesis deals with computer networks which play a key role in present society. More and more demands are placed on these networks (especially on quality of services and throughput) because of fast-growing developement of services such as voice and video real-time transmissions. All the packets in typical Ethernet networks are equal. Therefore it is sometimes impossible for the application to maintain required throughput speed of a network. For this case it is useful to take some mechanisms into the consideration. These mechanisms (sometimes called QoS) are able to distinguish different types of transmissions and traffic, analyze them and then prioritize them according to some pre-defined set of rules. The most famous mechanisms are Integrated Services and Differentiated Services. The implementation of Differentiated Services is the goal of this thesis.
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Fabricius, Marián. "Zajištění QoS v UMTS síti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218065.
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Diploma thesis deals with assign and distribution quality of service in mobile UMTS telecommunication networks. The project consists of two parts, theoretical and practical. Theoretical part of the project is focused to familiarize with functionality of the UMTS network with the main aspect at admission mechanism in radio part of the network as well as quality of service assign mechanisms according to service demands within core network of UMTS. Practical part of the project is given to simulation program OPNET Modeler and its capabilities in network design and testing various parameters of UMTS network with implementation quality of service mechanism. As the asset of diploma thesis becomes designed functional prototype of UMTS network with various options for individual settings user equipment as well as fixed mobile networks nodes.
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Kolmačka, Jan. "Zajištění QoS v bezdrátových sítích." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218563.
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The diploma thesis gives the overall information about the field of wireless networks of standards 802.11 and Quality of Service (QoS). The practical measurements describe the reactions of multimedia dataflows in the networks 802.11a/b/g/n. The individual standards, offered services, access methods and the network architecture are analyzed in the theoretical part. In the following part there is written about QoS and its basic parameters. Moreover, the standard 802.11e and the question of QoS in the wireless networks are explained in a detailed way. The first part of the practical measurement is focused on the networks 802.11b/g/n. All main network statistics are measured when using the wireless stations and routers. The projection and implementation of the wireless network in the Opnet Modeler is included in the next part. The individual simulations WLAN in the Opnet Modeler are comparing the networks 802.11a/b/g. The analysis of the key QoS statistics is undertaken; the measured data are clearly displayed in the charts and schemes. The interpreted results are concluded and justified.
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Figurny, Roman. "Podpora QoS v MANET sítích." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219468.
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The theoretical part of Master's thesis has been dealing with issues of MANET networks, issues of providing quality of services in MANET networks and analysis of various implementations of quality of services in these networks. At the start of the practical part of this thesis was described modified OLSR process model with support of quality of services. In simulation program OPNET Modeler was designed a topology of MANET network, firstly was run a simulation of this network without any support of quality of services and then was run a simulation with support of quality of services. The results of these simulations were analyzed, compared and graphically interpreted. In the next part of this thesis was designed a real MANET network with OLSR support. OLSR network communication was captured with the use of Wireshark. In the last part of this thesis was firstly described a meaning and functions of plugins in OLSR implementation and then was developed a plugin which is responsible for sending messages which contain a state of the links between nodes of MANET networks.
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Porwal, Rupesh. "Adaptive Selective Flooding Qos Routing." Thesis, Indian Institute of Science, 2002. https://etd.iisc.ac.in/handle/2005/3924.
Full textAbstract:
The routing strategy used in today's Internet is best-effort service, where all data packets are treated equally. This type of service is not suited for applications such as video conferencing, and video on demand, that requires the availability of certain resources (such as bandwidth) to be guaranteed for them to function properly. The routing in this context, called Quality-of-Service (QoS) Routing, is the problem of finding suitable paths that meet the application's resource requirements.
The majority of proposed QoS routing schemes operate by maintaining the global state of the network, and using this knowledge to compute the QoS route. However, all these schemes suffer from the inherent drawback of scalability, because of the need for each node to collect state information about the complete network. The other type of QoS routing schemes do not maintain network state information, but instead flood the network with QoS connection establishment requests. This type of scheme suffers from excessive message overhead during QoS connection establishment.
In this thesis, we present a new QoS routing algorithm that is a combination of the above-mentioned two schemes (i.e., global state and flooding based). The algorithm aims at minimizing the message overhead associated with these two schemes and still maintaining the positive aspects of both of them. The basic idea of the algorithm is: to reach to a destination, the path(s) will always pass through a specific set of intermediate nodes. The algorithm discovers such intermediate nodes (limited by a hop count threshold value needed to reach there). When a QoS connection request arrives at a node, it selects the feasible path leading to the intermediate node for the requested destination. The QoS connection establishment message (or routing message) is forwarded along this path. When the message arrives at the intermediate node, the further path is decided through same logic. To decide the path that leads to the intermediate node, the algorithm maintains the link state related to these intermediate nodes, and link state updates are restricted only with regard to these intermediate nodes. Because of this restriction in link state updation, one has less message overhead, compared to the global state based routing scheme. Further, the algorithm tries to group these intermediate nodes in such a way that the routing message need be sent to only one of the grouped intermediate nodes, and still makes sure that all the possible paths are covered. Therefore, one has a reduced message overhead because of grouping.
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Porwal, Rupesh. "Adaptive Selective Flooding Qos Routing." Thesis, Indian Institute of Science, 2002. http://hdl.handle.net/2005/51.
Full textAbstract:
The routing strategy used in today's Internet is best-effort service, where all data packets are treated equally. This type of service is not suited for applications such as video conferencing, and video on demand, that requires the availability of certain resources (such as bandwidth) to be guaranteed for them to function properly. The routing in this context, called Quality-of-Service (QoS) Routing, is the problem of finding suitable paths that meet the application's resource requirements.
The majority of proposed QoS routing schemes operate by maintaining the global state of the network, and using this knowledge to compute the QoS route. However, all these schemes suffer from the inherent drawback of scalability, because of the need for each node to collect state information about the complete network. The other type of QoS routing schemes do not maintain network state information, but instead flood the network with QoS connection establishment requests. This type of scheme suffers from excessive message overhead during QoS connection establishment.
In this thesis, we present a new QoS routing algorithm that is a combination of the above-mentioned two schemes (i.e., global state and flooding based). The algorithm aims at minimizing the message overhead associated with these two schemes and still maintaining the positive aspects of both of them. The basic idea of the algorithm is: to reach to a destination, the path(s) will always pass through a specific set of intermediate nodes. The algorithm discovers such intermediate nodes (limited by a hop count threshold value needed to reach there). When a QoS connection request arrives at a node, it selects the feasible path leading to the intermediate node for the requested destination. The QoS connection establishment message (or routing message) is forwarded along this path. When the message arrives at the intermediate node, the further path is decided through same logic. To decide the path that leads to the intermediate node, the algorithm maintains the link state related to these intermediate nodes, and link state updates are restricted only with regard to these intermediate nodes. Because of this restriction in link state updation, one has less message overhead, compared to the global state based routing scheme. Further, the algorithm tries to group these intermediate nodes in such a way that the routing message need be sent to only one of the grouped intermediate nodes, and still makes sure that all the possible paths are covered. Therefore, one has a reduced message overhead because of grouping.
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Dammak, Marwa. "Application du codage réseau aux plate-formes des jeux en ligne." Thesis, Cergy-Pontoise, 2018. http://www.theses.fr/2018CERG0961/document.
Full textAbstract:
L’application de jeu en ligne massivement multijoueurs fournit une grandepartie du trafic Internet global. Le trafic est généralement composé d’unepetite partie de données utiles encapsulé dans des segments TCP, entrainantun volume élevé d’entêtes transmis via le réseau. Cela implique: 1) la tailledes paquets est trop petite pour un routage efficace et; 2) la bande passanterequise par le serveur augmente. Par conséquent, il est nécessaire de trouverdes techniques de transmission et de routage plus efficaces afin de réduire levolume de trafic et augmenter l’efficacité du réseau permettant de prendre encharge le nombre croissant des joueurs. D’autre part, la qualité d’expérience(QoE) dans le contexte des jeux en ligne est fortement liée à la consistance.Cette consistance est influencée par la qualité de service (QoS) offerte parle réseau, principalement en termes de délai, de gigue et d’ordre de paquets.Par conséquent, une solution qui améliore ces paramètres aidera à satisfairedavantage de joueurs et à améliorer la qualité de service.L’objectif de cette thèse est de proposer des solutions pour améliorerla qualité d’expérience des jeux en ligne en augmentant la consistance devue, en réduisant les délais et en augmentant l’efficacité du réseau. Pour leproblème de consistance, nous proposons une topologie de réseau cyclique.Cette topologie ordonnée facilite la mise en place des procédures de gestionet de contrôle de la transmission pour imposer un ordre causal entre tousles joueurs. Concernant le délai et l’efficacité du réseau, certains ont proposé l’application de la technique du tunnel, compression et multiplexage(TCM). Cependant, les paquets transmis avec TCM sont plus grands queceux d’origine, ce qui nécessite plus de temps pour les transmettre et augmente le risque de saturation au niveau des fils d’attente. Nous proposonsl’utilisation de la technique de codage réseau (NC) qui permet d’augmenterle débit dans certaines conditions de topologies et de routage. Cette technique permet aux nœuds intermédiaires d’encoder les paquets qu’ils reçoivent plutôt que d’effectuer une simple fonction de stockage et de transfert. Celapeut réduire la charge de trafic, réduire les délais et augmenter l’efficacité duréseau.Dans cette thèse, nous proposons des modifications pour améliorer latechnique TCM et nous évaluons ses performances. De plus, nous proposonsd’ajouter le concept de partition des joueurs et de changer la topologie d’unarbre à une forêt. Nous étudions ensuite la topologie cyclique. Nous concevons un protocole de routage optimisé sur une topologie en cycle baséesur la technique de codage réseau. Puis, nous évaluons ses performances entermes de délai, de charge et d’ordre. Les résultats montrent que l’utilisationdu codage NC permet de réduire la charge et le nombre de paquets transmis, garantir un ordre de paquet par période et de réduire le délai. Eneffet, on peut gagner jusqu’à 14% de latence avec notre protocole par rapport à un protocole de routage optimisé sans codage réseau. Par la suite,nous proposons un scénario de mise en pratique de cette solution sur une infrastructure Device-to-Device. Nous validons les limites théoriques du délaien utilisant des simulations réseau et nous discutons ensuite des contraintespratiques qui s’imposent lors de l’implémentation dans un réseau réel. Finalement, nous proposons des solutions pour ces contraintesThe application of massively multiplayer online games provides a large partof the global internet traffic. The traffic is typically encapsulated in TCPsegments of small size information (the so called payload) resulting in a highvolume of headers transmitted through the network. This implies the following: 1) the packets’ size is too small for efficient routing and; 2) thebandwidth required by the server seems to be increasing. Therefore, it isnecessary to find more efficient transmission and routing techniques to reduce the traffic’s volume and to increase the network’s efficiency in orderto support the growing number of players. On the other hand, Quality ofExperience (QoE) in the context of online games is strongly influenced byconsistency. This consistency is influenced by the quality of service (QoS) offered by the network, mainly in terms of delay, jitter and order of the packets.As a result, a solution that enhances these parameters will help in satisfyingmore players and subsequently improving QoE.The goal of this thesis is to propose solutions to enhance the QoE of onlinegames by increasing the consistency of view, reducing the delay and increasing the efficiency of the network. For consistency, we propose a cyclic networktopology. This ordered topology facilitates the implementation of transmission management and control procedures to impose a causal order betweenall players. As for the delay and the efficiency problem, some have proposed the application of Tunneling, Compression and Multiplexing (TCM)technique. However, the transmitted packets with TCM are larger than theoriginal ones, which requires more delay to transmit them and increases therisk of congestion. We propose the use of the Network Coding technique(NC) which makes it possible to increase the bit rate of the network undercertain topological and routing conditions. This technique allows intermediate nodes to encode the data they receive rather than perform a simple”store and forward” function. It can reduce the traffic load, reduce the delay and increase the network’s efficiency.In this thesis, we propose some modifications to enhance the TCM technique and evaluate its performance. Besides, we propose to add the playerspartition approach and change the topology from a tree to a forest. Afterwards, we investigate the cyclic topology. We design an optimized routingprotocol over a cycle topology based on the network coding technique andevaluate its performance in terms of delay and order. The results show thatby using NC coding, one can gain up to 14% of latency over an optimizedrouting protocol for the cycle topology without the use of network coding.Afterwards, we propose a practical implementation scenario of this solutionover a device-to-device (D2D) infrastructure. We finally validate the theoretical limits of delay using network simulations and discuss a number ofpractical constraints
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Frikha, Ahmed. "On providing Qos and reliability for telecommunication networks : multi-domain Qos routing and multicast reliability." Rennes 1, 2012. http://www.theses.fr/2012REN1S067.
Full textAbstract:
Dans cette thèse, nous étudions deux problèmes majeurs dans les réseaux de télécommunications actuels. Tout d'abord, nous étudions le problème de la fourniture de la qualité de service (QoS) pour les nouvelles applications dans des réseaux multi-domaines. Précisément, le problème de calcul de chemins inter-domaine et multi-contrainte (ID-MCP) est profondément étudié dans la première partie de cette thèse. Dans la deuxième partie, nous étudions la fiabilité des communications dans les réseaux, qui est essentielle pour les services à contraintes strictes. Plus précisément, nous abordons le problème de la garantie de fiabilité des communications multicast. En effet les conséquences d'une panne d'un nœud ou d'un lien dans ce cas d'étude est grave puisque plusieurs destinations peuvent être déconnectées simultanément à la suite d'une seule panne. L'objectif de la première partie est de trouver des nouvelles approches qui permettent de résoudre le problème ID-MCP (inter-domain multi-constrained path computation problem), tout en respectant les politiques des opérateurs des réseaux, à savoir préserver la confidentialité des informations de routage et l'autonomie des domaines. Nous proposons trois nouveaux algorithmes basés sur les éléments de calcul de chemins (PCEs), algorithmes nommés respectivement: ID-PPPA, ID-MEFPA et HID-MCP. Les deux premiers algorithmes utilisent le pré-calcul qui permet de réduire le temps de calcul tout en maintenant un taux de succès élevé. Le troisième algorithme est basé sur un calcul hybride qui bénéficie à la fois des avantages du pré-calcul et du calcul à la demande. L'algorithme HID-MCP utilise des mécanismes de retour en arrière (crankback) pour améliorer le taux de succès global. Les performances de nos algorithmes proposés sont prouvées avec précision par des études analytiques et des simulations. L'objectif de la deuxième partie est de trouver des structures de protection des nœuds et des liens adaptées à la diffusion multicast. Comme le temps de restauration est un critère important dans le processus de reprise de routage (recovery), nous proposons l'étude de la protection des communications multicast au niveau de la couche optique DWDM. Une nouvelle génération de p-cycles adaptés à la structure de diffusion multicast et aux contraintes imposées par les réseaux tout-optiques, est proposée dans cette partie. Nous proposons également trois nouveaux algorithmes pour la protection des nœuds et des liens dans un trafic multicast dynamique, algorithmes nommés respectivement CCHN, NPCC et NPCC-SSC. Le premier algorithme utilise un ensemble de p-cycles candidats bien sélectionnés afin de réduire le temps de calcul et d'optimiser l'utilisation de la bande passante. Différentes approches pour la sélection des ensembles de p-cycles candidats sont étudiées. Le deuxième algorithme NPCC étend le concept de protection des nœuds avec les p-cycles pour une structure de diffusion multicast. Le troisième algorithme étend notre algorithme NPCC pour résoudre les contraintes imposées par les réseaux tout-optiques, telles que le nombre limité de commutateurs optiques capables de splitter un signal lumineux et la contrainte de continuité de la longueur d'onde. Les simulations prouvent que nos algorithmes peuvent assurer une bonne utilisation des ressources ainsi qu'une faible probabilité de blocage tout en réduisant le temps de calculIn this thesis, we study two major problems of today’s telecom networks. First, we study the problem of providing Quality of Service (QoS) guarantees for IP-based services in multi-domain networks. Precisely, the Inter-Domain Multi-Constrained Path (ID-MCP) computation problem is deeply investigated in the first part of this thesis. Second, we study networks reliability, which is essential for many services, namely mission-critical services. Specifically, we address the problem of ensuring reliable multicast communications. Indeed, the consequences of a node or link failure are dramatic in this case of study as multiple destinations could be disconnected simultaneously. The objective of the first part is to find new schemes that enable solving the ID-MCP problem while respecting the operators policies, namely preserving the routing information confidentiality and the autonomy of the domains. We propose three new algorithms based on the Path Computation Element (PCE) framework, named respectively : ID-PPPA, ID-MEFPA and HID-MCP. The first two algorithms employ a pre-computation scheme that allows the computational time to be reduced while maintaining a good acceptance rate of the requests. The third algorithm is based on a hybrid computation scheme that takes advantages from the pre-computation and the on-demand computation. The HID-MCP employs crankback mechanisms to improve the global success rate. Performances of our proposed algorithms are accurately proven through both analytical studies and simulations. The objective of the second part is to find node and link protection structures suitable for multicast diffusion. As the restoration time is a crucial criteria in the recovery process, we address the reliability of multicast communications at the DWDM optical layer. A new generation of p-cycles adapted for multicast diffusion structures as well as the constraints imposed by all-optical networks, is proposed in this part. We also proposed three new algorithms for node and link failure recovery in dynamic multicast traffic, named respectively CCHN, NPCC and NPCC-SSC. The first algorithm uses a set of well-selected candidate p-cycles in order to reduce the computational time and achieve a significant bandwidth saving. Different approaches for selecting the candidate p-cycle sets are investigated. The second algorithm, NPCC, extends the node protection concept of p-cycles for multicast traffic. The third algorithm extends our NPCC algorithm to deal with the constraints imposed by all-optical networks, such as sparse light-splitting and wavelength continuity constraints. Simulation results prove the efficiency of our algorithms in terms of resource utilization, blocking probability and the computational time
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Neto, Paulo Jorge Mendes Cardoso. "Arquitecturas IPTV." Master's thesis, Instituto Politécnico de Leiria, 2010. http://hdl.handle.net/10400.8/1355.
Full textAbstract:
Dissertação apresentado à Escola Superior de Tecnologia e Gestão do IPL para obtenção do grau de Mestre em Engenharia Informática - Computação Móvel, orientada pelo Professor Doutor Carlos Manuel da Silva Rabadão.Os operadores de telecomunicações de todo o Mundo estão a investir em novas formas de fornecer aos seus clientes serviços de TV + Voz + Internet, em redes IP unificadas, que proporcionam novas oportunidades de negócio, e serviços inovadores, onde o IPTV se encaixa na perfeição. Esta dissertação propõe um estudo na área de IPTV, com especial atenção nas arquitecturas de rede, codecs, protocolos, QoS/QoE, e redes wireless. O serviço de IPTV é extremamente sensível a perdas e atrasos de pacotes nas redes de cabo, mas nas redes wireless existem outras condicionantes que degradam o serviço ainda mais. Baseado neste estudo é testado o comportamento de live stream multicast (Live IPTV), nas redes wireless, que apresentam várias limitações quando operam com IP multicast. Os testes são realizados numa rede laboratorial, que é uma réplica dum segmento existente na rede wireless da freguesia da Memória, concelho de Leiria. São realizados testes com o mesmo vídeo codificado nas qualididades SD, HD e FHD.
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Bereketli, Alper. "On Qos Multicast Routing Routing Protocols." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606446/index.pdf.
Full textAbstract:
Multicasting is a technique used for distributing data packets from one or more sources to a set of receivers on interconnected networks. Currently developing network applications bring specific quality of service (QoS) requirements like bounded delay, minimum bandwidth, and maximum data loss rate. Providing the required quality of service addresses routing and resource reservation concepts. In this study, a literature survey is carried out on traditional and QoS multicast routing protocols, and the need for QoS routing protocols is investigated. QoS multicast routing protocols are classified and compared according to their multicast tree construction and resource reservation approaches. Two QoS protocols, QROUTE and QMBF, are selected, and their performances are experimentally compared using the network simulation tool Network Simulator-2 (ns-2). The objective of the simulations is to compare the QoS routing algorithms and their tree construction efficiencies. The first contribution of the thesis is the survey and classification of traditional and QoS multicast routing protocols. Another contribution is the ns-2 implementation of two QoS multicast routing protocols. The final contribution of the thesis is the performance evaluation of the recent protocols from a different perspective.
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Al-Dalati, Issam. "Enhanced QoS in Wireless Certified USB." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19966.
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Our study investigates the performance of the WUSB standards and compares it to the Wimedia Standard. To the best of our knowledge, no technical contributions exist in the open literature at present simulating WUSB and its performance. The study showed that WUSB can achieve better throughput when bursting is enabled at the maximum burst size and it provides more accurate timing control of device activity than using the standard facilities of the WiMedia MAC. Our study also addresses protocol extensions and improvement to the original WUSB standard to support better Quality of Service (QoS). First improvement enables a di erent reservation mechanism along with contention based access to support higher priority security and medical system monitoring applications. Second improvement enables the host device to use an adaptive packet loss technique to change the packet size dynamically during the data transmission to achieve packet loss less than 10%. Third improvement enables redundancy in the cluster by adding a backup host to prevent mobility failures and changes. This backup host is chosen by a prede ned cost weighting function.
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Zhong, Yu. "Global QoS management for multicasting applications." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26825.
Full textAbstract:
In a multicast network of a large number of receivers where transmission resources and end-systems are of high heterogeneity, the receivers require automatically selected heterogeneous QoS stream variants that meet their end-system requirements. In this thesis, we introduce a Receiver Satisfaction Driven (RSD) method that takes into account user preferences stored in user profiles in order to automatically select the stream variants that maximize the overall user satisfaction. In the case of a large number of receivers, the receivers may be partitioned into different user classes according to their bandwidth limit. Each class is allowed to send one or several representative group profiles, depending on the number of users in that group. The source processes the data from the group profiles and determines the optimal QoS parameters for a given number of stream variants. Our simulation results show that the streams variants generated based on representative group profiles give a reasonable satisfaction level for all receivers.
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Ikram, Imran. "Traffic Engineering with MPLS and QOS." Thesis, Blekinge Tekniska Högskola, Avdelningen för telekommunikationssystem, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1217.
Full textAbstract:
In the modern era there exist applications that require very high resources and generate a tremendous amount of traffic so they require considerable amount of bandwidth and QOS to operate and perform correctly. MPLS is a new and a fast technology that offers much remuneration both in terms of providing trouble-free and efficient security together with the high speed of switching. MPLS not only guarantees quality of service of IP networks but in addition to provides scope for traffic engineering it offers many enhanced features of IP networks as it does not replace IP routing, but works along with existing and future routing technologies to provide high-speed data forwarding between label-switched routers (LSRs) together with QOS. Many network carriers are facing the problem of how to accommodate such ever-growing demands for bandwidth. And the static nature of current routing algorithms, such as OSPF or IS-IS, the situation is going even worse since the traffic is concentrated on the "least cost" paths which causes the congestion for some links while leaving other links lightly loaded. Therefore, MPLS traffic engineering is proposed and by taking advantage of MPLS, traffic engineering can route the packets through explicit paths to optimize network resource utilization and traffic performance. MPLS provides a robust quality of service control feature in the internet. MPLS class of service feature can work in accordance with other quality of service architectures for IP networks.
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Xu, Tie. "Packet voice over non-QoS networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0007/MQ45259.pdf.
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