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Laboratory of Quality of Service
Eltahir Ahmadon, Ahmed ; Kolka, Zdeněk (referee) ; Polívka, Michal (advisor)
The Bachelor's work, you are reading, deals with the issue of VoIP calling and measurement its quality. In the following paragraphs the discussion will be about the basics of networking protocols such as TCP, UPD, IP and SIP, after that a preliminary introduction to QoS issues - ways of measuring voice quality for instance MOS and E-Model. Importance of implementing QoS for VoIP, and QoS parameters used in the proposed services (will be called "mechanisms"), such as Best effort service, Integrated and Differentiated services. Based on these fundamentals points with designed laboratory for quality of service. The laboratory will be aimed at testing the quality of codecs with regard to bandwidth, jitter, delay and packet loss. The solution lies in the fact that, which codecs are actually suitable for the service.
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A system for monitoring the quality of connectivity
Vyskočil, Vladimír ; Peterka, Jiří (advisor) ; Děcký, Martin (referee)
The aim of the theses is to design a methodology for centralized monitoring of data traffic in an ISP network that would detect individual connection with connectivity problems, and evaluate these problems. The methodology should at least evaluate packet loss and latency between a centrally located monitoring point and endpoints at user premises. A further goal is to implement this methodology, test it and evaluate the results.
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Measurement of transfer speeds and delays in computer networks
Bárdossy, Adrián ; Kubánková, Anna (referee) ; Jeřábek, Jan (advisor)
Bachelor thesis is interested in measurement of transfer rate and latency in computer networks. In the first part of thesis is defined, which motodics of measurement we know, various RFC and their specifications, also various parameters about measurement in computer networks like bit rate, capacity of channel, latency. In the second part are prepared users interfaces and softwares for applying the measurement of thesd parameters. In the last part is application of these softwares and creating and testing methodic of network measurement.
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Measurement of influence of network impairments on VoIP call quality
Zelenay, Martin ; Krkoš, Radko (referee) ; Šilhavý, Pavel (advisor)
This work explores, analyzes and rates influence of network impairments on VoIP traffic. It describes how voice over IP is carried according to standards. There are described concepts and basics of VoIP networks with orientation on facts necessary to understand analyzed actions and measurements in theoretical part. In practical part, there is described realization of tests according to instructions with orientation on initial checking of devices and rating models and then measurement of influence of network impairments on quality of calls with use of these devices and Opensource PBX Asterisk.
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Laboratory of Quality of Service
Eltahir Ahmadon, Ahmed ; Kolka, Zdeněk (referee) ; Polívka, Michal (advisor)
Abstrakt Bakalářská práce se zabývá problematiku IP telefonie, emulace sítě a kvalitou službou (QoS). Kapitol 2 pojednává o model TCP/IP a OSI, síťových protokolech (IP, TCP, UDP) a o protokolu SIP. Kapitole 3 se zabývá problematikou QoS, definicí QoS, QoS ve službách s reálným časem, parametry a způsoby změření kvality hlasu – subjektivními a objektivními testy. Na základě získaných poznatků byla navržena laboratoř kvality služby. Laboratoř je zaměřena na testování kodeků z hlediska kvality přenášeného zvuku, s ohledem na šířku pásma a ztrátovost paketů. Laboratoř kvality služby byla navržena tak, aby byly splněny požadavky na subjektivní testy uvedené v kapitole 3. 4. Návrh laboratoře Schéma navržené laboratoř je zachyceno na obr. 4.1. Návrh je složen ze čtyř hlavních částí – Dvou softwarových IP telefonů (XLite), síťového emulátoru (WANem Wide Area Network emulator), a SIP ústředny (3CX Phone System pro Windows od 3CX Ltd). Sestavování spojení prbíhá podle stejného schématu viz obr. 4.1. Oba koncové uzly jsou připojeny přes emulátor WANem. Počítač, na kterém je emulátor instalován má dvě síťová rozhraní. PC1, resp. PC2 s WANem tvoří lokální síť 1 (LAN1), resp. lokální síť 2 (LAN2). Pakety prochází z jednoho uzlu do druhého přes WANem. WANem emuluje chování skutečné WAN sítě, umožňuje provádět v laboratorním prostředí testy na síti s přesně definovanými parametry. Návrh celé laboratoře je virtualizován. Je využita platform VirtualBox od Oracle. Podrobně je návrh popsán v kapitolách 4.1 a 4.2. QoS měření Během měření byly dva parametry sítě proměnné, resp. přesně určené nastavením WANemu – šířka pásma a ztrátovost. Protože testování probíhalo v místnosti, ve které se nachází elektronická zařízení a jiné zdroje ruchů, byla metoda ACR daná doporučením ITU-T P.800 upravena viz kapitola 4.3.1 Testovanému subjektu byly testovací nahrávky přehrávány do sluchátek. Dle ITU-T Rec. P.800 doporučuje několik metod hodnocení kvality služby – MOSLQ, MOSLE, MOSLP, ACR a CCR. K praktickému ověření funkčnosti navržené laboratoře byla vybrána modifikována verze ACR (M-ACR). Použité náhravky obsahují tři věty, mezi něž jsou vloženy mezery (volný interval – bez zvuku). Výsledky subjektivních testů jsou shrnuty v tab. 4-1 až tab. 4-10. MOS byl vypočítán pomocí rovnice (3. 1), jehož výsledky shrnuty v tab. 4. 11. Závěr Navrhovaná laboratoř byla úspěšně otestována, návrh splnil očekávání. S využitím navržené laboratoře proběhly subjektivní testy kodeku G.711 na 10 osobách.
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Open-Source Software Tools for Network Diagnostics
Loffay, Pavol ; Ráb, Jaroslav (referee) ; Matoušek, Petr (advisor)
The aim of this work is to make a research of existing open source tools, which are concerned with the diagnosis of the network transmission in the form of measuring of throughput and other basic parameters. The work is devoted to the construction of methodics for testing and comparing devices between themselves. The result of the work is recommendation to an ordinary customer the right application for measuring of given network transmission parameter.
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Extension of Behavioral Analysis of Network Traffic Focusing on Attack Detection
Teknős, Martin ; Zbořil, František (referee) ; Homoliak, Ivan (advisor)
This thesis is focused on network behavior analysis (NBA) designed to detect network attacks. The goal of the thesis is to increase detection accuracy of obfuscated network attacks. Methods and techniques used to detect network attacks and network traffic classification were presented first. Intrusion detection systems (IDS) in terms of their functionality and possible attacks on them are described next. This work also describes principles of selected attacks against IDS. Further, obfuscation methods which can be used to overcome NBA are suggested. The tool for automatic exploitation, attack obfuscation and collection of this network communication was designed and implemented. This tool was used for execution of network attacks. A dataset for experiments was obtained from collected network communications. Finally, achieved results emphasized requirement of training NBA models by obfuscated malicious network traffic.
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Diagnostic tool for RTP sessions
Sirotný, Miroslav ; Komosný, Dan (referee) ; Šimek, Milan (advisor)
This work was divided into two parts. In the first part are worked out protocols RTP and RTCP with theory. In this part I show to what these protocols are used. The second part is dedicated to proposal of application for the diagnosis of transmission parameters RTP / RTCP relations. Programs like Tcpdump win, Wireshrak, IP / TV Viewer and the Java programming language with development setting NetBeans 5.5.1. were used while creating the application. In this part we focused mainly at two important parameters like Jitter and Packet Loss.Functionality applications. Finally, we have verifed the function of the application on Multicast Network with running IPTV.
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Optimalization and analysis of communication services latency dependencies
Zikmund, Lukáš ; Škorpil, Vladislav (referee) ; Endrle, Pavel (advisor)
This master’s thesis is focused on ensuring of Quality of Service (QoS) in wireless network for standards IEEE 802.11 a/b/g/n. First part of this thesis is focused on the theory of this issue. It covers methods of data transfer in computer networks and individual transfer parameters especially on parameters needed to ensure quality of service. It also describes standards for wireless data transmission and protocols for real time data transmission. The second part is devoted to OPNET modeler and to simulations created on this program. Simulations are focused on real-time data transfer and compare the standards in terms of delay and jitter.
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Mobile IP in MANETs
Raška, Martin ; Hošek, Jiří (referee) ; Skořepa, Michal (advisor)
This thesis discuss about the problem with mobility of stations in IP networks, concretely protocol Mobile IP and about the problems with this protocol in MANET networks, with the scope on Motorola MESH. First part is about design integration of protocol Mobile IP in this networks with usage Tropos 5210 MetroMesh routers and Cisco components (router, switch) to design and configure wireless MESH network, than connect this network with Cisco components and try to implement Mobile IP into this network. Second part is about design and configure wireless network from Cisco Wireless Access Points and about succesfully implementation of Mobile IP protocol into this network. In the last part is some tests of the function and quality of this topology.
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