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Automatic configuration of intermediate networking devices used in Cisco academy
Verner, Lukáš ; Jeřábek, Jan (referee) ; Komosný, Dan (advisor)
his semestral´s thesis deals with proposal and system implementation for automatic configuration of Cisco network devices. This system is called AutoConf and it is intended for distant copying configuration files from eagle-server to the switches and routers in Cisco academy laboratory. It is handled by web pages placed on eagle-server. In this system, user can create new laboratory exercises with configuration files for network devices and then these files could be used for configurations. Informations about done configurations are saved in relation database MySQL. Network devices which will be configured by system AutoConf have to be connected with eagle-server. To setup their connection settings was created decision-making mechanism. If it detects physical connection between network device and eagle-server before network device starts, it will set network device for communication with eagle-server.
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Analysis, features and applications of available current mode multipliers
Miksl, Jan ; Jeřábek, Jan (referee) ; Šotner, Roman (advisor)
The diploma thesis deals with analysis, validation, measurement of parameters of the commercially available current multiplies (namely the EL2082 and EL4083) and their applications in practice. Control analysis are carried out in OrCAD PSpice program and compared with values from datasheets. Control analysis are focused on AC and DC characteristics of these active blocks. There are discusses the input impedance, the output impedance, the current gain and the possibility of electronic adjusting. The parameters of the elements were verified by measurements. Proposals for circuit applications (selective circuit, oscillator, frequency filter) with EL2082 and EL4083 are presented and analyzed in the program OrCAD. Three oscillator circuit designs are experimentally tested and the results are compared with the theoretical expectations and simulations in OrCAD. The possibility of electronic control for oscillators is examined. Also the sensitivity and the tolerance analysis are carried out. The constructional details of oscillators are presented at the end of this work.
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Design of measuring solutions for circuits with differential signals
Jemelík, Lukáš ; Hanák, Pavel (referee) ; Jeřábek, Jan (advisor)
This master´s thesis deals about a measuring structures of elements working at a current mode. There were outlined structures for measuring input and output impedance. These structures were simulated for DACA element. It deals with a voltage to current and current to voltage converters. All structures and converters were simulated at computer program PSpice. Selected variant were practically verified and control measuring was realized.
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Design of labs for Cisco academy courses
Oujezský, Václav ; Růčka, Lukáš (referee) ; Jeřábek, Jan (advisor)
This master's work deals with the design of laboratory exercises for Cisco Academy courses. Especially is oriented on Cisco technology. The theoretical part describes various devices used in the laboratory and the issue of functionality of these devices, such as switching, routing and solve any problems with the configurations of these elements. The practical part is directly generated designs laboratory exercises, focusing on specific examples of the problems from the configuration and network management with Cisco. An integral part of work consists of supporting the presentation of individual laboratory tasks, including configuration files, settings of the device. Create labs and verify the functionality of their configuration has been realized in the laboratory Cisco Academy Brno.
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Differential frequency filters with modern active elements
Kubík, Milan ; Vrba, Kamil (referee) ; Jeřábek, Jan (advisor)
The master thesis focuses on design of fully-differential frequency filters with modern active components in current mode. First part informs about problems concerning analogue frequency filters and creating differential structures. Second part deals with methods of create filters and used active components - DACA (Digital Adjustable Current Amplifier) and MO-CF (Multiple Output Current Follower). Own design of differential filters is divided on two parts. In the first part of design results there are filters created with synthetic higher-order elements. There are presented circuit structures implementing the third order low pass filter and high pass filter. In the second part are designed filters with signal flow graphs. The first circuit implementing low pass, high pass, band pass, band rejection and all-pass filter. The second circuit is with help of the same set of current amplification by DACA components tuning of the natural frequency. For this circuit was make sensitivity analysis. In the final part is practical implementation of the differential frequency filter for tuning of the natural frequency and summarises the thesis.
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Analysis of security and authentication of wireless networks
Kulíř, Tomáš ; Jeřábek, Jan (referee) ; Szőcs, Juraj (advisor)
This master's thesis deals with wireless networks, mainly about the WiFi. It deals with summary of individual security mechanism both theoretically and using them in real hardware. Mainly it is interested in the security of the individual mechanisms and their weaknesses, which cause rupture of security. At each chapter the ideas and methods, that the attackers are trying for infiltration of wireless networks and decrypt encryption WEP, WPA or WPA2, are outlined. The principle of the authentication of the WiFi by the authentication server and its options, which is connected with directory service LDAP, is also explained in this thesis. The penultimate chapter deals with the summary of security mechanisms and references that should be adhered by design of the WiFi for the provision of the high security. The ending of the master's thesis is devoted to social engineering and its most famous representatives.
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Simulation scenarios in NS2 demonstrating knowledge of BGP and multicast
Sobotka, David ; Komosný, Dan (referee) ; Jeřábek, Jan (advisor)
Network simulation can be beneficial not only in solving problems while applying new standards or recommendations, but also primarily an aid in understanding and verifying knowledge of behaviour of communications protocols. The aim of the thesis is to create illustrative tasks in the simulation environment, Network Simulator 2 (NS-2), which are designed to verify the behavior of BGP and multicast. Created tasks are above all devoted to BGP, which is the cornerstone of routing information of all IP networks conglomerate, the Internet. The first two tasks designed for BGP use the implementation of ns-BGP and the remaining are based on the implementation of BGP++. The tasks verify both the function of basic attributes of the protocol, influencing the decision making process when routing information (AS_PATH, MED, LOCAL_PREF, WEIGHT), and furthermore the methods or parameters affecting the efficiency of the process of routing and a reduction of excessive network traffic (BGP confederation, routing, aggregation, MRAI). The last task regards multicast, more specifically the type of DM, which is a group of the so-called Dense Mode. The task illustrates how to join/leave groups and spread messages of types GRAFT and PRUNE under a constant data stream.
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Electronic tunable harmonic oscillator
Veselý, Jiří ; Jeřábek, Jan (referee) ; Šotner, Roman (advisor)
This masters project describes properties and primary parameters of active function blocks (OPA, VCA, OTA, CFA, CC) usable in construction of harmonic oscillators. Basic principles of harmonic generators, especially feedback oscillators, are introduced. In next section are presented five particular schematics of harmonic tuned oscillators. For this oscillators are indicated basic formulas, essential qualities performed by simulations and results of sensitivity and tolerance analysis. In the last part of diploma thesis there are selected three circuits which are made and their features are measured.
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Design and realization of V/I and I/V symmetrical converters
Chrást, Jakub ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
Master´s thesis deals about design of symmetrical converters voltage on current and current on voltage. These converters will be used for measuring frequency characteristics of differential frequency filters. Current feedback amplifier was used as active element. Some circuits useful for this function were chosen. Various integrated circuits were put into these circuits. All variations were simulated in computer program Orcad. In terms of computer simulations the best variation was chosen. Selected variants were practically verified and control measuring were realized.
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Active Frequency Filters with Minimal Configuration
Preclík, Milan ; Jeřábek, Jan (referee) ; Koton, Jaroslav (advisor)
This work deals with exploitation of multiple current and voltage gates of active components. After that an optimal circuit´s scheme choice, its simulation and subsequent realization of frequency filter follow. First of all there is a common description of frequency filters and current and voltage conveyors. Furthermore the text focuses on searching circuit´s schemes of second-level frequency filters, described by characteristical equation. These equation make an easy numerical concept possible. New circuits with one active component and with a minimal number of pasive components are searched by using the method of autonomous circuits. The choice of resulting circuit based on simulations executed in Orcad is next in line. The work concludes with verification of a proper function of our filter.
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