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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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Simulation of communication part of modern industrial networks
Beneš, Pavel ; Blažek, Petr (referee) ; Fujdiak, Radek (advisor)
The thesis is focused on simulating of protocols from standard IEC 61850 in simulation tool OMNeT++. The theoretical part in the thesis deals with description of the field of operating technologies, supervisory control and data acquisition and protocols Tase-2/ICCP, IEC 61850, IEC 60870-5-104, DNP 3 and DLMS/COSEM. Next part deals with parameters influencing connection and description of simulation tools NS2/NS3, OPNET and OMNeT++. In the practical part there is created a network containing protocols from the standard IEC 61850 in the simulation program OMNeT++. Then in the network a end to end delay and packet loss with increasing traffic is measured.
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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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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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Wireless communication link analyzer
Dostálek, Jakub ; Burian, František (referee) ; Jílek, Tomáš (advisor)
The aim of this bachelor thesis is to design and implement a wireless communication analyzer in mobile robotics, using IPv4 protocol and Ethernet interface and to create correctly selected and expressed characteristics from the measured data, according to which the wireless communication channel can be further optimized for the best data transmission. To meet these requirements, a brief search of existing solutions was performed, their applicability was discussed and important parameters of the wireless transmission channel were defined, which will form the given characteristics. Furthermore, the actual design and implementation of a wireless communication link analyzer for previously specified required parameters, verification of its functionality on the transmission link with known parameters and automation of measurement and data evaluation was performed.
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Measurement of qualitative parameters in the access network
Kejík, Tomáš ; Slavíček, Karel (referee) ; Grenar, David (advisor)
The theme of this bachelor’s thesis is „Measuring of qualitative parameters in an access network.“ The aim of this paper is a characterization of multimedia broadcasts in access networks and the creation of a functional network generator. The theoretical part of the paper is dedicated to analyzing key broadcasting parameters, which affect the resulting quality of network broadcast. Furthermore, used network protocols that are given for network and multimedia broadcast are analyzed. Simulation is done by using of GNS3 software. After that, transferred data were measured. Side effects affecting the functionality of the resulting transmission were subsequently analyzed. Another part of the paper is the practical part, which is focused on creation of a network generator by using the Bash language and making a script to facilitate turning on the generator for different counts of clients. At the end of the paper, the broadcast parameters were evaluated.
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Implementation of HDLC protocol in network simulators
Polášek, Jaromír ; Mašek, Pavel (referee) ; Pokorný, Jiří (advisor)
This diploma thesis deals with the possibility of using HDLC (High-Level Data Link Control) protocol for communication and addressing of smart metering devices with a data concentrator. The HDLC protocol is used in two DLMS/COSEM (Device Language Message Specification/Companion Specification for Energy Metering) communication profiles. To simulate these communication profiles, the most appropriate simulation program is selected. Using this simulator, the first communication profile is implemented and the second one is designed. Communication profile based on TCP/IP (Transmission Control Protocol/Internet Protocol) has been fully implemented. To implement the three-layer HDLC communication profile, all options have been thoroughly explored. Using these findings, a process was designed to guide the full implementation. For the first communication profile the qualitative parameters are measured, which are then plotted and evaluated.
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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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Optimization of data transit in network
Řezáč, Michal ; Škorpil, Vladislav (referee) ; Kubánková, Anna (advisor)
This bachelor thesis is divided into two parts. The first part deals with and describes necessary teorethical units, together with analyse of ISP network and other input informations. These findings are further used in second part of bachelor thesis. The practical part dealt with testing of optimization mechanisms in the laboratory network. Thereafter has been done a wider tests of optimization mechanisms based on different ways of marking data streams and deploying these rules. The advantages and comparision of these methods were further evaluated.
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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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