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Measurement of qualitative parameters in the access network
Kejík, Tomáš ; Slavíček, Karel (referee) ; Grenar, David (advisor)
The theme of this bachelor’s thesis is „Measuring of qualitative parameters in an access network.“ The aim of this paper is a characterization of multimedia broadcasts in access networks and the creation of a functional network generator. The theoretical part of the paper is dedicated to analyzing key broadcasting parameters, which affect the resulting quality of network broadcast. Furthermore, used network protocols that are given for network and multimedia broadcast are analyzed. Simulation is done by using of GNS3 software. After that, transferred data were measured. Side effects affecting the functionality of the resulting transmission were subsequently analyzed. Another part of the paper is the practical part, which is focused on creation of a network generator by using the Bash language and making a script to facilitate turning on the generator for different counts of clients. At the end of the paper, the broadcast parameters were evaluated.
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Representation of Solutions of Linear Discrete Systems with Delay
Morávková, Blanka ; Růžičková, Miroslava (referee) ; Khusainov, Denys (referee) ; Diblík, Josef (advisor)
Disertační práce se zabývá lineárními diskrétními systémy s konstantními maticemi a s jedním nebo dvěma zpožděními. Hlavním cílem je odvodit vzorce analyticky popisující řešení počátečních úloh. K tomu jsou definovány speciální maticové funkce zvané diskrétní maticové zpožděné exponenciály a je dokázána jejich základní vlastnost. Tyto speciální maticové funkce jsou základem analytických vzorců reprezentujících řešení počáteční úlohy. Nejprve je uvažována počáteční úloha s impulsy, které působí na řešení v některých předepsaných bodech, a jsou odvozeny vzorce popisující řešení této úlohy. V další části disertační práce jsou definovány dvě různé diskrétní maticové zpožděné exponenciály pro dvě zpoždění a jsou dokázány jejich základní vlastnosti. Tyto diskrétní maticové zpožděné exponenciály nám dávají možnost najít reprezentaci řešení lineárních systémů se dvěma zpožděními. Tato řešení jsou konstruována v poslední kapitole disertační práce, kde je řešení tohoto problému dáno pomocí dvou různých vzorců.
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Distance measurement between nodes in IP networks
Šimák, Jan ; Novotný, Vít (referee) ; Komosný, Dan (advisor)
This thesis deals with delay prediction issue between nodes on the Internet. Accurate delay prediction helps with choosing of the nearest internet neighbor and contributes to effective usage of network sources. Unnecessary network load is decreased due to algorithms of delay prediction (no need for many latency measuring). The thesis focuses theoretically on the three main algorithms using coordinate systems - GNP, Vivaldi, Lighthouses. Last one is at the same time the main subject of the thesis too. Algorithm Lighthouses is explored in detail theoretically and in practise too. In order to verify the accurate of delay prediction of Lighthouses algorithm the simulation application was developed. The application is able to compute node coordinates of synthetic network using Lighthouses algorithm. Description of simulation application and evaluation of simalution results are part of practice part of this thesis.
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Analysis of delay dependence of modern communication services and channels, QoS optimization
Rozman, Jiří ; Szőcs, Juraj (referee) ; Endrle, Pavel (advisor)
The main aim of this thesis is to familiarize with options of services using real-time data transfer in wireless networks. Theoretical part presents wireless network based on IEEE 802.11 standard and its practical use. Large part is focuses on 802.11e standart, that provides support for quality of service in wireless networks. Furthemore this thesis deals with transport and applicaton protocols supporting multimedia streaming over computer network. Second chapter is focused on analyzing real computer network with purpose in measuring parametrs influencing quality of service such as bandwith, delay, jitter and loss. Last part deals with the design of wireless network in OPNET Modeler enviroment with focus on simulating parameters that influence quality of service.
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Measuring of data communication parameters in computer networks
Šeda, Pavel ; Hošek, Jiří (referee) ; Skořepa, Michal (advisor)
Master‘s thesis is focused on basic characteristics of data transmissions in computer networks. In forepart I digestedly described basic characteristics computer networks, metods of their measurement and valuation. Computer networks type LAN as well as wireless computer networks Wifi, are mentioned. In second part I realized my own proposition of basic characteristics measurement. This proposition is used for SW applications development. Main goal of these applications is measurement of packet delay, packet jitter, paket loss and available bandwidth. I described details of SW applications and realized measurement of real computer networks in the end.
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QoS optimization and modern communication services delay analysis
Novák, Přemek ; Škorpil, Vladislav (referee) ; Endrle, Pavel (advisor)
This thesis consists of theoretical and practical parts. The theoretical part contains an analysis of the problems of wireless networkssolutions individual standards and methodologies to ensure quality of service. In the practical part using the OPNET Modeler, a number of different simulation models and their evaluation. It is a model of individual standards, support mobility and interference effects on quality of service.
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Geolocation of Internet nodes based on communication latency
Horák, Michael ; Balej, Jiří (referee) ; Komosný, Dan (advisor)
This thesis covers the topic of determination of geographical location of a host in internet network while utilizing measurement of the end to end delay and implementation of Constraint-Based Geolocation. Gradually I go through issue of the delay in computer networks and ways how to measure it. Next chapter describes a few ways to geolocate host in internet network with emphasis on the CBG method. Another chapter is dedicated to describing a way to project spherical coordinates to the two dimensional space, which has been used in implementation of geolocation method. Chapter about implementation builds upon the facts given in previous chapters while functions of the program written in the JAVA programing language are being explained. Two similar geolocation methods were implemented. By comparing the results gained by implementation, new method of geolocation is proposed and devised. It combines properities of both previous methods. There are results of the implemented methods and their comparation to the one of the source documents used in creation of this thesis in summary section.
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Quality of service support in unix-like operating system for communication in WiFi networks
Mizera, Josef ; Komosný, Dan (referee) ; Novotný, Vít (advisor)
Diploma thesis is focused on the supporting of Quality of Services in wireless networks, especially in the Linux operation systems. The topic is connected not only with OS, but also with the wireless standard, which supports QoS in wireless networks called IEEE 802.11e. QoS is needed especially for time-consuming data transfers in real time. The theoretical part deals with the theoretical analysis of the issue of the QoS support. There are described parameters, which occurred in quality of services support. This section also deals with the division of services that are used to transmit data across computer networks. It also describes the QoS support in wireless networks according 802.11e, its implementation and methods of accessing a medium with a without possibility of traffic. This part is followed by a description of QoS support in UNIX operating systems. The chapter describes how is the QoS support designed in these operating systems. There are also characterized concrete tools which are used for control the data flow in the operating systems using Linux. At the end the theoretical part deals with different types of queues and methods used in linux OS. In the practical part of the thesis, there are various designed topologies and scenarios to verify the functionality of QoS support in wireless networks using a Unix system. These chapters show the results of different tests at selected transmission data streams that are sensitive to transmission time. There is also verified cooperation of QoS support between devices operating on the network and data link layers. The output of this work is to design a laboratory exercise for the subject Network Architecture. This exercise is focused on familiarization with the QoS support functionality in wireless networks and in Unix-like operating systems. This chapter also describes the devices and programs that are needed to measure this task. The last part of the chapter describes the procedure for the preparation of the measuring station. For this laboratory task, there is an inserted manual in the annex.
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Simulation of data transmission latency between nodes in IP networks
Balej, Jiří ; Molnár, Karol (referee) ; Komosný, Dan (advisor)
This master thesis is focused on the delays incurred in data transmitting over IP networks. The top of the paper is devoted to points, where delay is invoked and causes of the latency. For individual sources of delay are are described the parameters that affect the usual size of latency. The next section describes the types of networks and their typical delay. In the paper are also discussed tools for measuring delay and determining the number of intermediate devices. The thesis contains results of measurements delay time in the real network. For these results are listed conclusions about the delay for one intermediate device. There is also said general ratio of crow-fly distance and calculated distance. The last part deals the simulation of delay in the NS2 program. The results of thesis are scripts that shows the relation of delay and the number of switches, routers, and the length of the path.
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