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QoS assurance in wireless networks
Dvořák, Filip ; Vychodil, Petr (referee) ; Vymazal, Michal (advisor)
The bachelor´s work deals with wireless network WiFi and describes basic standards and their supplements. This work is divided into two parts - theoretical and practical. The first part of the work is applied to theoretic description of the best known standards IEEE 802.11 and detailed description of standard 802.11e. The second part of the work takes an interest in proposal and influence of service Wireless Multimedia in wireless network both in real world and in simulation program Opnet Modeler. Obtained results of the measurement are described and summarized in the conclusion.
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Wireless networks security analysis
Szőcs, Juraj ; Vychodil, Petr (referee) ; Vymazal, Michal (advisor)
This master’s thesis deals with analysis of security in wireless networks. There are desc- ribed various methods of security systems, such as WEP, TKIP and CCMP. There is also realization of attacks against the wireless network and there is analysis of security weaknesses. Then there are discussed possible defense mechanisms. Part of this work was also analysis of local security in certain areas and evaluation of their security.
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Wireless networks security and possible attacks on these networks
Vlček, Peter ; Vymazal, Michal (referee) ; Vychodil, Petr (advisor)
The first of the main objectives of this work was to examine and study the different types of attacks on wireless networks. This work is focused on the most commonly occurring types of attacks such as WEP/WPA/WPA2 cracking, a Man in the Middle attack (MIM), Dictionary attacks, MAC spoofing and finally Denial of Service attacks. Description of individual attacks is also accompanied by detailed instructions on how to carry out these attacks on the Windows platform. It is described how to detect various attacks and identified. It is then implemented software that is able to identify possible risk of selected types of attacks. This software belongs to a group of wireless intrusion prevention system (WIDS). It focuses on attacks WEP/WPA/WPA2 type of cracking, Dictionary attacks and MAC spoofing. For the implementation of defense against attack by a Man in the Middle (MIM) and Denial of Service attack would need special monitoring equipment.
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Potential application of neural networks in network elements
Babnič, Patrik ; Vymazal, Michal (referee) ; Vychodil, Petr (advisor)
The goal was to get acquainted with the problems of network elements to describe neural networks that can be used to manage such a feature. The theoretical part deals with the neural networks from their inception to the present. It focuses mainly on the network, witch can be used for management control. These are the two network: Hopfield network and Kohonen network. The practical part deals with the network element model and ist implementation. It contains a practical element model using a neural network, witch is controlled by a network element.
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Wireless and mobile UMTS networks simulation using QoS
Zapletal, Lukáš ; Vychodil, Petr (referee) ; Vymazal, Michal (advisor)
Diplomová práce je psána v angličtině a věnuje se standardu IEEE 802.11e, obsahujícím podporu kvality služeb a taky pojednává o kvalitě služeb QoS (Quality of Service) v systému UMTS. Rozebrány jsou hlavní teoretické pilíře daných mechanizmů a praktická část se zabývá simulacemi síťových modelů. Standard 802.11e objasňuje propojení vrstev na fyzické úrovni a zmiňuje metody přístupu k přenosovému médiu DCF, PCF, HCF, EDCA, HCCA. Dále přístupové kategorie a také odlišnosti v MAC podvrstvě, je rozebrána problematika při přenosu prioritních dat na základě identifikátorů. Vzpomenuta je taky struktura formátu rámce a techniky s rozprostřeným spektrem. Časové limity pro doručení prioritních dat a požadavky kladené na tyto data je možné snadno srovnat v tabulkách. Problematika kvality služeb je velice komplexní záležitost, nicméně jsou rozebrány základní klíčové parametry jako koncové zpoždění, jitter, zahazování dat, propustnost, velikost front a hodnota MOS. Zmíněny jsou i mechanizmy integrovaných RSVP a diferencovaných služeb pro zajištění QoS. U systému třetí generace UMTS je objasněna architektura a společná kooperace se systémem GSM. Vzájemné propojení obou sítí je zřejmé z obrázků. Zvýšený zájem je věnován vrstvovému modelu a funkcím RRM pro zajištění QoS. Objasněny jsou různé druhy předávání hovorů, tzv. Handover Control a funkce Admission Control. Rozebrány jsou jednotlivé třídy provozu Conversational, Streaming, Interactive a Background. Praktická část se odehrává v simulačním prostředí programu OPNET Modeler. Byly vytvořeny dva modely s různými scénáři pro srovnání zajištění QoS. Model objasňující princip standardu IEEE 802.11e obsahuje dvě bezdrátové sítě s přístupovými body a stanicemi, na kterých jsou sledovány simulace s různým zatížením přenášených dat. Pro porovnání výsledků je zkoumán rozdíl při použití metody HCF v síti s podporou QoS. Model UMTS sítě obsahuje základnové stanice Node B s možností vysílání do tří sektorů. Mobilní účastník pohybující se po trajektorii představuje princip funkce Softer Handover. Konfrontace mezi scénáři je zastoupena kompresí záhlaví pomocí funkce PDCP a rozlišení Type of Service. Obzvláště je sledováno chování prioritních dat hlasu a videa u obou sítí. Naměřená data zastupují grafy a průběhy výsledních charakteristik. Analýza diskutuje odlišnosti u sítě bez podpory a s podporou kvality služeb. Rozdíly jsou porovnány a vyhodnoceny dle metodiky QoS. Součástí práce je i řešení problémů při návrhu UMTS sítě a podány jsou taky užitečné tipy a návrhy na jejich odstranění. Projekty v simulačním softwaru jsou popsány dle postupu vyhotovení, avšak hloubka podrobností je potlačena. Detaily nejsou rozebírány, protože se očekává pokročilá znalost mechanizmů a jistá dávka zkušeností s programem.
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QoS assurance in wireless networks
Kolmačka, Jan ; Vychodil, Petr (referee) ; Vymazal, Michal (advisor)
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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Safety risks of current routers
Bubelíny, Peter ; Vymazal, Michal (referee) ; Vychodil, Petr (advisor)
The thesis aims to study and document the problem router security. It present the characteristic information about a router, functions, types and locations in a computer network. Because router is integrated part of network, next are described the most commonly types of attacks and generally available security technologies. The thesis also offers insight into the router as a safety device in the role of the throat network, part of the deeper security infrastructure or access point in wireless networks. Next are described the selected security technologies against some of already mentioned attacks and also are offered opportunities to improve safety router. The next are demonstrated DoS and brute-force attacks on router in ethernet network and attacks based on sniffing packets on router in wireless network. Finally, the results are presented.
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Software design support of burglar alarm system
Vymazal, Michal ; Pelka, Tomáš (referee) ; Burda, Karel (advisor)
This thesis deals with implementation of software support of alarm system design for security levels 1 and 2 based on web technologies. It was created intuitive and interactive graphical interface that allows to create high-quality alarm system design even for laymen. First of all the paper deals with standards and jurisdictions in the Czech Republic, according to which the alarm system design must be followed. In theoretical part there are described in detail characteristics of alarm systems and its components, proper functioning principles, installation principle, advantages and disadvantages of use, individual steps of alarm system design and proposed methodology of alarm system design for security level 1 and 2. In practical part there are described the technologies used for the implementation of this paper, structure of created webpage and detailed steps of alarm system design, as seen by user during creating. The result of this paper is a webpage, which is divided into two parts: theoretical and practical. The theoretical part provides information about the alarm system architecture, alarm system design and established methodology for the alarm system design for security level 1 and 2. In the practical part the user, on the basis of gained information and interactive help, can create high-quality alarm system design that meets all the conditions for reliable function in real traffic.
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Efficiency of Wireless Networks from Services View
Buchta, Marek ; Vymazal, Michal (referee) ; Škorpil, Vladislav (advisor)
Subject of this thesis was the issue of effectiveness of wireless networks from the perspective of services. Become acquainted with WiFi network standard IEEE 802.11 with protocols and principles of WiFi networks and services. It should be focused on the quality of service QoS. In teoretical part of this thesis are described problems considering wireless networks, layer model and types of nets used in WiFi. Standard IEEE 802.11 is analysed in details including supplements and used packets. Special attention is paid to the quality of service QoS. Next are discussed the principles and application services as VoIP, videoconferencing, video streaming and others in WiFi network. On the basis of obtained knowledge is designed extensive WiFi network with assured supply of services. For modelling and simulation of wireless network is used software development environment Opnet Modeler. Model of wireless network is used to optimize and analyse this wireless communication network. In thesis are also simulated properties of data which are sensitive to delay. In last part of thesis is created a laboratory work, which contains a submission of task, detailed theory, wiring diagram, instructions for elaboration, guidelines for simulation and example of elaboration of task. Work is about comparison of network with used 802.11b and 802.11e standard, and support of quality of service QoS.
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Intrusion Detection and Prevention Systems
Černý, Michal ; Vymazal, Michal (referee) ; Pust, Radim (advisor)
The detection and intrusion prevention systems could be realized as independent hardware or set in the software form on to the host. The primary purpose of these protective elements is the undesirable activity detection such as integrity intrusion of the files, invalid attempts while connecting to the remote service or acquisition of the local network data. The systems react to the event on the basis of the action that is defined by internal rules. We can include the caution sending or communication blocking among possible counteractions. The base principals of the detection and intrusion prevention systems are described in the dissertation. Various types of captured data analyses and processes of the inhere rules creation and further more caution formats are mentioned in the dissertation. There are also considered the alternatives of their location including advantages of selected situations. There is described the installation and setting up of particular elements of the realized network and security systems. In order to the verification of functionality and factor of the protection providing there was realized several selected types of attacks.
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