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Node localization on the Internet using artificial coordinate systems
Škvor, Martin ; Molnár, Karol (referee) ; Komosný, Dan (advisor)
This thesis is focused on methods for nodes localization in Internet using latency prediction in synthetic coordinates systems. Thesis also deal with methods, which latency prediction between nodes is based on other systems. Among such a methods particularly belongs King, which uses DNS (domain name service). Furthermore, thesis deal with relevance of overlay networks in latency prediction and their use for different services. Practical part of this thesis concentrates on method for latency prediction in synthetic coordinate system Global Network positioning. There were made two programs for counting coordinates of landmarks and hosts in this system. Measurements and calculations made in this thesis, are focused to determine accuracy of latency prediction of this method and their evaluation is made at the end of thesis.
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Analysis of the effect of delay and window size on TCP connection efficiency
Kavický, Martin ; Komosný, Dan (referee) ; Molnár, Karol (advisor)
Content of master’s thesis is description field of Sliding window and it’s expansion algorithms, witch are Slow start, Congestion avoidance, Fast Retransmit and Fast Recovery algorithm. Thereinafter is described creation of model in Opnet Modeler’s simulation area. In this simulation area was analyzed reactions of average transfer speed onto variance of data size, lost ratio, latency in short and long time slot and variance of receiver’s buffer size. In last section of this document is method design witch makes it possible of transfer speed control through the use of receiver’s buffer size dynamic setting.
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Simulation of data transmission latency between nodes in IP networks
Balej, Jiří ; Molnár, Karol (referee) ; Komosný, Dan (advisor)
This master thesis is focused on the delays incurred in data transmitting over IP networks. The top of the paper is devoted to points, where delay is invoked and causes of the latency. For individual sources of delay are are described the parameters that affect the usual size of latency. The next section describes the types of networks and their typical delay. In the paper are also discussed tools for measuring delay and determining the number of intermediate devices. The thesis contains results of measurements delay time in the real network. For these results are listed conclusions about the delay for one intermediate device. There is also said general ratio of crow-fly distance and calculated distance. The last part deals the simulation of delay in the NS2 program. The results of thesis are scripts that shows the relation of delay and the number of switches, routers, and the length of the path.
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Implementation of service functions for work with MIB database in simulation environment OPNET Modeler
Ruml, Martin ; Skořepa, Michal (referee) ; Molnár, Karol (advisor)
Implementation of service for work with MIB database is subjeckt the bachelor’s thesis. MIB database is system database which is instrumental for storage of control informations in network elements. A first chapter is instrumental like a introduction to the control computer networks. A second chapter describes the basic features of protocol SNMP. The protocol SNMP is a standardized application protocol which uses for a transmission control informacions from and to the system database MIB. The protocol is based on a draft manager-agent when the manager is mostly active who enquire of the agent for the values of concrete items. A next chapter deals with a structure and standards for the MIB database. It describes a basic enbranchment among the administrative organizations. A main part of working is devoted to a proposal and a implementation of servece functions MIB database. The main requirements for the MIB database in light of a cooperation with the protocol SNMP are identified in this chapter. These processes are trained-in to the experiment implementation of MIB database. The implementation is written in C++. A header file of the classes and supportive functions who implement basic mechanisms of MIB database and its methods for a tender the database created from the proposal. The header file contains the several processes for an easement of cooperation MIB database with the application protocol SNMP, too. A final chapter shows the using of designed classes. The created programe is equipped with a graphics interface who uses the functions for a local access. Very easy modul for the comunication with the database through the messages of SNMP is among next shown functions in the programe.
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Implementation of a simulation model for a simplified DiffServ-MIB database
Zeman, Otto ; Hošek, Jiří (referee) ; Molnár, Karol (advisor)
The aim of this work is to propose feasible solution for the simulation of the SNMP (Simple Network Management Protocol) protocol in the OPNET Modeler simulation environment. This work describes in detail individual procedures, which were chosen for this simulation . The work also contains an introduction to the OPNET Modeler simulation environment, the SNMP protocol, the DiffServ model and the DiffServ-MIB database. The main part of this work describes the algorithms programmed to model the functions of the SNMP protocol. Source codes of the algorithms programmed are included as well. The work deals especially with the functions for obtaining values from different levels of a multilevel model attributes, packet creation functions with dynamically changing length of user-data field, for the implementation process of a simplified DiffServ MIB database and with the functions for statistic creation.
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OLSR routing protocol for MANET networks in OPNET Modeler simulation environment
Hošek, Petr ; Molnár, Karol (referee) ; Růčka, Lukáš (advisor)
The first part focuses on general routing of computer networks. It describes the importance of routing, basic elements, algorithms and protocols. It also describes the so-called MANET networks, where there are discussed routing protocols in these networks. The next chapter deals with the analysis of routing protocols OSPF version 3 and OLSR protocol. For both protocols basic algorithms, their use and structure are described. In OSPF protocol there is also described historical development and differences between versions 2 and 3. The OLSR protocol properly describes the principle of MPR nodes, which is one of the most important parts of the protocol which differs it from the others. Next there is a brief introduction of a powerful simulation tool OPNET Modeler which allows simulating the operation and behavior of almost any computer network with a very extensive possibility of options for the functioning of the entire network, as well as nodes it selves. The practical part is divided into five parts. The first section describes the structure of process models, the basic elements, variables, and block editors OSLR routing protocol in OPNET Modeler program. The second part is devoted to the ICI data structure, which is used for inter-process communication and verify the creation and reception of messages using this function. The third part deals with the process model of OLSR routing model. There is a description of various blocks and functions involved in its function of protocol and significance. The fourth chapter shows an extension of data unit protocol OLSR HELLO messages to other fields, which is able to transmit a numeric value between neighboring stations, and these values print it in the console. The last block of the practical part is dedicated to creating its own message which is broadcast between stations like part of the OLSR packet messages. This message includes the parameter of actual data traffic rate of each communicating stations. These values are for each station exported to an external file for later processing.
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Analysis of VoIP implementation in the WAN network of Třinecké železárny a.s.
Pieniažek, Ireneusz ; Skořepa, Michal (referee) ; Molnár, Karol (advisor)
This diploma thesis is focused on the implementation of the technology VoIP in the remote branch offices of a big company. There are used the current WAN lines, which have been so far used only for transfer of data. Implementation of IP telephony is extending the utilization of those lines and at the same time the costs for running of the telephone services are reduced. There are described the models for proposal and also the proposal for solution of IP telephony for a specific company.
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Modern wireless technologies - 802.11n
Bednář, František ; Molnár, Karol (referee) ; Skořepa, Michal (advisor)
This work describes new standard 802.11n for wireless network. The work contains two parts: theoretical and practical. Theoretical knowledge and understanding our problems will be used in design and simulation wireless network. Theoretical part will discuss about function and methods, which the standard picking over from older standard 802.11a, 802.11g a about new features, that should raise transmission data rate and throughput on MAC sublayer dramatically. Data rate of networks based on standard 802.11n will be comparable with Ethernet networks. Main features that increase data rate on PHY layer is method of multiple antennas calls MIMO and use 40 Mhz channel. On MAC layer will be add frame aggregation that cause linear dependent of throughput on MAC layer and data rate on PHY layer. In practical part we will pay attention simulation of stream video high definition in wireless network. This part contain design and components configuration in network. We will be able to compare simulation results individual standards, by creation of several duplicate scenarios.
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Routing protocols for MANET network with focus on QoS
Potfay, Attila ; Molnár, Karol (referee) ; Vajsar, Pavel (advisor)
The main task of this master’s thesis is to simulate the routing protocol AODV (Adhoc On-Demand Distance Vector Routing) to the Network Simulator ns-3 environment, and to realize a model of MANET (Mobile Ad-hoc Network) network with the support of Quality Of Service (QoS). Further implement the protocol AODV in real devices and the involvement of such nodes in the simulation process using the simulator ns-3. This work provides the theoretical basics: it deals with the primary characteristics of MANET, describes in detail the routing protocols MANET with support of QoS, provides information about the Network Simulator ns-3 simulation environment, describes in detail the existing implementation solutions of the protocol AODV in to real devices and provides information about the methods of involvement real devices to the simulation.
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Design and realization of client application for cooperation with ONET Modeler
Polak, Martin ; Jelínek, Mojmír (referee) ; Molnár, Karol (advisor)
The bachelor thesis „Design and realization of client application for cooperation with OPNET Modeler“ is about trying to bring a client to easier and better communication with the server. Open new opportunities for effective work in the network. Goal of this work is to interconnect two communication stations, which will together communivate. OPNET communicates with an external program which redirects the data to the network layer. The work describes the individual steps in creating a model client. Part of the work is introduction to the OPNET Modeler simulation environment, whereupon it is tied together a detailed desciption of programming of an external application.
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