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Increasing the efficiency of the handover in real network environment
Michalec, Richard ; Sobotka, Jiří (referee) ; Vajsar, Pavel (advisor)
The aim of this work is to study methods of handover used in WiMAX and WLAN networks, next suggest the posibility of simulation methods for WLAN handover in the simulation environment OPNET Modeler. This work is focused primarily on obtaining the information about neighboring AP and subsequent selection of a new AP using such information. The work describes in detail each processes solutions that are used to implement newscanning methods
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Design of Communication system among Moving Vehicles
Klampár, Marián ; Polívka, Michal (referee) ; Škorpil, Vladislav (advisor)
The purpose of this thesis is to show up possibilities of inter-vehicle communication and to introduce new approaches in communication for the purpose of enhancing the security and the fluency of vehicle transportation. This thesis also highlights vulnerabilities in communication. The main goal is the analysis of existing technology and the design of protocol for data transfer with focus on minimizing handover time of informations. Part of the design is a simulation of communication based on acquired information.
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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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Security Protection efficiency improvement for Wireless Networks
Marušek, Michal ; Burda, Karel (referee) ; Škorpil, Vladislav (advisor)
Nowadays every wireless radio-communication services encompass huge type of technology used for transfer video, voice or data. Wireless communication is the most expanded branch and many companies are using this technology because of low cost and simply management. The biggest advantage is easy connection to shared wireless medium and allows users of network to move around whole covered area. The most expanded types of wireless networks are called Wireless LAN (WLAN). With rising number of WLANs is rising chance to attack shared wireless medium by hacker and many sensitive information can be stolen or modified. To avoid this chance was created the first security protocol used in WLAN called WEP. Its goal was protect data transmitted trough WLAN as strong as were protected in wired networks. Unfortunately WEP was hiding a big weakness which can be used in a crack of WLAN in a minute with the aid of special software. Example of this kid of software can be Airsnort constructed to monitor shared medium and captured every packet transferred trough this medium. Based on statistical method Airsnort can obtain hidden password in a few minutes. The second type of this software can be Aircrack-ng, which can crack hidden password without any user connected to WLAN. Aircrack-ng uses active techniques to generate network load and can obtain password more effectively and faster. The result of both cases was successful and protection of WLAN was completely cracked. Later was created new security protocol called WPA, which had to fix the cryptography weakness of previous WEP. WPA was only temporary security protocol, during standard 802.11 was developing which had to offer highest security and integrity protection of transferred data trough WLAN. For this reasons was created new version of WPA called WPA2 which satisfy requirements of standard 802.11i. Both protocols WPA/WPA2 contain weakness, which can crash security of WLAN. This crack is based on authentication PSK. Attacker during authentication is using information from four-way handshake between user of WLAN and access point. Based on this information attacker can crack password with the aid of password list attack which took approximately 30 minutes. Based on previous result is important to chose strong password contains alphanumeric string or special strings with satisfy length.
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Implementation of Quality of Service into Wireless Networks
Kaman, Štěpán ; Růčka, Lukáš (referee) ; Škorpil, Vladislav (advisor)
Wireless networks are currently the frequent access connection to the local network or the Internet. Until 2005 there was no support in the 802.11 standard priority data and the use of multimedia services in these networks is problematic. Thesis deals with the standard IEEE 802.11 standard and quality of service support including IEEE 802.11e. They discussed methods of access to transmission medium, differences in the MAC sublayer, the reader issues in the transmission of priority data and the requirements for these data. In Opnet Modeler was created wireless network with access points and stations on which they are carried out simulations at different strain of transmitted data. It studied the difference in the use of DCF and EDCF method, used in the network with QoS support. In particular, it examined the behavior of priority voice and video data in both networks. The focus is on key parameters such as throughput, dropping data, packet loss, delay, jitter and the size of broadcasting front. The measured data are analyzed, and differences in the network without the support and promoting the quality of services are compared and evaluated. Part of this work is the role of laboratory in the Opnet Modeler.
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Security risks of wireless access networks
Špidla, Milan ; Hošek, Jiří (referee) ; Polívka, Michal (advisor)
Master´s thesis „Security risks of wireless access networks“ deals with wireless access networks, which are the most widespread in this time. The main target is realization of attacks wireless access networks protected by various using methods. This thesis shows main securities gaps, which originate from project this networks. These securities gaps are used for realization attacts in practical part. In the next part I took attention of network´s monitoring possibilities.
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Security prospects of wireless communication networks
Hráček, Jiří ; Lambertová, Petra (referee) ; Škorpil, Vladislav (advisor)
This master thesis deals with all types of wireless networks security – in personal, local, metropolitan and also mobile networks. This work is mostly focused on wireless local area networks (WLANs), which are the most widespread at nowadays. This work describes attacks to the wireless local area network, attackers steps and possible protection against it. Some of these attacks are tested in practical part of this work. In this master thesis there were also designed and created two laboratory exercises. One of them is a simulation in the wireless network using Opnet Modeler application. The other exercise is strictly practical type.
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Solution of the authentification and authorization for wireless local networks
Čížek, Michal ; Pust, Radim (referee) ; Burda, Karel (advisor)
This thesis is about available priciples and methods of authentication and authorization in wireless local area networks. First part is about available methods of authentication with short description each of them and usage analysis for small and middle-sized wireless networks. There is a project of authentication and authorization for school wireless network of three access points in the second part of the thesis, including description of Mikrotik RouterOS configuration and FreeRadius configuration. In the end of the thesis there is a project tests and usage analysis.
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Indoor positioning systems, implementation and realization
Strnad, Pavel ; Bruckner, Tomáš (advisor) ; Pavlíček, Luboš (referee)
Bachelor thesis deals with the topic of localization inside buildings. The first part deals with the technologies and systems used for localization, while explaining the basic princi-ples and problems of implementation of these systems, their benefits and disadvantages. This section explains the functionality of each technology and the purpose for which it is best suited. The next part deals with the actual implementation of the localization system Redpin within the campus of the University of Economics in Prague. This section summarizes basic information about the project Redpin, then there is dismantled architecture of the system and its functionality. The remaining part is devoted to the direct implementation of this system. There are specified used technologies, decommissioned installation process and eventually re-evaluated results of its testing.
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Metropolitan Wi-Fi Networks - Technology, Organization, Users Administration
Klaška, Jan ; Šalamon, Tomáš (advisor) ; Rydzi, Daniel (referee)
Bakalářská práce se zabývá metropolitními Wi-Fi sítěmi a aspekty jejich provozování. Jejím cílem je uvést čtenáře do problematiky, což se neobejde bez vysvětlení principů technologie Wi-Fi samotné. Bakalářská práce je rozdělena do tří oddílů. V prvním oddílu jsou rozebrány principy této technologie, zmíněna je historie bezdrátových sítí, produkty určené pro budování bezdrátových sítí, probrány jsou jednotlivé specifikace rodiny standardů IEEE 802.11 pro Wi-Fi zařízení. Uvedeny jsou také způsoby zabezpečení určené pro Wi-Fi sítě a výhody a nevýhody technologie Wi-Fi. Druhá část práce je poté věnován metropolitním sítím samotným se zaměřením na síť CZFree.net. Rozebrána je organizace této sítě, topologie, billing (účtování) a další. Na konci kapitoly lze najít srovnání cen a podmínek poskytovatelů bezdrátového připojení do Internetu pomocí Wi-Fi technologie. Ve třetí části se nachází kapitola Quality of Services (QoS), kde je tato problematika hlouběji probrána.
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