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Porting OpenVPN to Windows CE Platform
Ešner, Oldřich ; Ráb, Jaroslav (referee) ; Ryšavý, Ondřej (advisor)
The motivation for inception of this MSc. thesis which follows on from a term project of the same name was the transfer of the application for building private virtual OpenVPN networks from Windows XP operating system to Windows CE Embedded 6.0 platform. The project deals with virtual private networks in general and looks more closely at its implementation - OpenVPN. It also introduces the basic features of the Windows CE operating system. The project goes on to describe device drivers in NT-based Windows operating systems, the Windows Driver Model used, the NDIS network interface model and also the model of Windows CE drivers - the Stream Interface Model. The project continues with a~description of communication in OpenVPN application and primarily the role of TUN/TAP virtual network interfaces. This is followed by a proposal for transfer of TUN/TAP adapter drivers together with a description of limitations and necessary modifications between both platforms. As a result a TAP network device driver is implemented whose function is verified by test application that emulates the behaviour of a TUN adapter. The project concludes with an evaluation of the achieved results, the possibilities for further work on this theme and with the overall contribution of this project.
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OTDM to WDM conversion
Kupčiha, Lukáš ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The aim of this thesis was introducing the options of conversion between OTDM and WDM technologies. Since this issue is rather extensive, first of all the principle of optical transmission system is described. One chapter presents the effects influencing the optical transmissions. Material absorption, linear and nonlinear scattering and bending losses are mentioned in terms of fiber losses, followed by description of waveguide, chromatic and polarization-mode dispersion of optical fibers. Last part of the chapter presents nonlinear effects, including self-phase modulation, cross-phase modulation and four-wave mixing. The practical part of the thesis deals with multichannel systems. The principles of frequency, space a hybrid multiplexing are explained. Multichannel systems with optical time domain multiplexing and waveguide multiplexing are described in detail and compared. The elements of the transmission chain of multiplex, such as different types of lasers, detectors, modulators, optical amplifiers, splitters, couplers, MUX and DEMUX are discussed. The next part of the thesis was aimed at suggesting the model of mutual conversion between OTDM and WDM systems. First of all, the previously performed experiments concerning the conversion between OTDM and WTM were evaluated. Then the model of OTDM/WDM/OTDM conversion was designed, with explanation of its parts and their function. The general recommendations for practical implementation were are also included. Due to the limited amount of time reserved for access to the simulation program Optsim, the simulations were performed only for certain parts of the proposed conversion model. At the end of the thesis, the proposed model is evaluated.
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Design of optical amplifier
Somora, Rastislav ; Číž, Radim (referee) ; Slavíček, Karel (advisor)
This Bachelor's thesis deals with design and construction of support circuits for a modern optical amplifier the SOA. In the first chapter, optical transmitting medium with its physical properties and types of used cabels is described. The overview includes a list of optical cables, their damping properties and parasitic effects which can occur durring comunication. Next chapter is focused on the optical signal sources used in modern data networks, describes their internal structure and physical essence. Third chapter is dedicated to designing the optical amplifier with the SOA circuit. It focuses on the right choice of parts, their arrangement and layout of the design. Last chapter deals with set up, calibration and control of the optical amplifier module.
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Design of semiconductor optical amplifier
Somora, Rastislav ; Hanák, Pavel (referee) ; Slavíček, Karel (advisor)
Diploma thesis deals with the construction of a moder semiconductor optical amplifier SOA. In the first chapter optical comunication and the use of optical amplifiers is described. In the next chapter some types of optical fibers, their chemical composition and properties are described in detail. The third chapter overviews optical amplifiers, their use today, describes their advantages and disadvantages and their proper use in optical comunications. The fourth chapter describes the solution of the objective, the right layout of separate blocks and connections used in measurements. Fifth chapter describes used components, describes their basic parameters and proper use in circuit. The last chapter evaluates outputs of measurements and their impact on the objective.
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Software defined networks
Flimel, Peter ; Smékal, Zdeněk (referee) ; Filka, Miloslav (advisor)
This diploma work describes the software-defined network focusing on optical networks. Subsequently designed their own software network that is implemented in the environment OMNeT ++. This work deals with SDN (software-defined network), and impact on current communications environment in the world of telecom-munications services.
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Design and management of WDM systems for optical networks
Červenka, Vladimír ; Šporik, Jan (referee) ; Tejkal, Vladimír (advisor)
This thesis describes single types of wavelength-division multiplex (WDM) according to the International Telecommunication Union (ITU-T). This work offers an overview of components and evaluation of critical parts of network design utilizing WDM technology. There are depicted typical properties, suitable components and channel spacing for each category. Suitable optic fibers according to ITU-T and characteristics of negative effects can be found in the work as well. Furthermore, there are presented most important optic sources, optic amplifiers, optic detectors with filters their requirements and application. They are especially important for achieving operation of WDM system. The fifth chapter considers impact of negative effects in fiber optics and their influence on the system. Then, a WDM system is designed along with management and monitoring the physical layer. The work also presents 1,33 Tbit/s (32 × 42,7 Gbit/s) WDM transmission over 300 km (with three 100 km spans) of post-compensated non-zero dispersion-shifted fiber (NZDSF) LEAF. The capacity of 400 Tbit/s×km is achieved in a single 25,6 nm C band using non-return-to-zero differential phase-shift-keyed modulation (NRZ-DQPSK), balanced detection and erbium-doped fiber amplification. Together with design of transmission system a several simulative analysis has been carried out in order to find the optimum configuration (such as number and distances between amplifiers, length of spans or the way of dispersion compensation) for a high bit rate optical transmission system. It was used a program OptiSystem 8.0.
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Optical amplifiers for metropolitan and access networks
Čech, Martin ; Šporik, Jan (referee) ; Tejkal, Vladimír (advisor)
Aim of this Master´s thesis is to describe and compare most common types of optical amplifiers used in today’s networks. The first section focuses on problematic of optical transmissions and phenomenon which cause degradation of transmitted signal. It is also explained in this section why there is a need to deploy optical amplifiers. Next section describes basic principles, structure and properties of individual types of optical amplifiers. Following section describes simulations which were made to compare the performance of transmission systems with each individual type of optical amplifier. The last section contains a design of optical metropolitan network with wavelength multiplex. Based on simulations from preceding part best amplifier type and optimal amplifier placement was selected. Functionality of the design was tested and simulations described in final section.
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Connecting the TV studios
Flimel, Peter ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
In this bachelor thesis work is done TV link study in 2020, for the purpose of mediation football matches between studies in Prague and Bratislava. This work deals with optical connections and technology matters to revel in the transmission of large amounts of data.
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Effect of optical connectors quality on transmission
Bernkopf, Miroslav ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
This diploma thesis deals with optic fiber connectors and their influence on transmissions realized via fiber optics. Optical fibers and lightguides play the key role in telecommunications because of constant demands of higher bandwidth and data rates. Original metalic wires do not meet market requirements and so the fiber optics are more and more being used. There are various types of fibers and there are also many ways of connections. This work deals with demountable way of connection – optical connectors, which have the biggest influence on a total attenuation and route length. Connector has to meet various requirements such as cleannes, quality, mechanical construction and ferrule polishing.
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Simulation of high-speed optical data transmissions
Chaloupka, Tomáš ; Münster, Petr (referee) ; Horváth, Tomáš (advisor)
The aim of this master thesis is comparation of simulation tools OptSim™ and PHO- TOSS which are used to create simulations of data traffi cs in access and metropolitan networks. The outcome of this thesis is three laboratory exercises and their theoretical bases which should explain the way of working in diff erent simulation environments to students.
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