• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 41
  • 20
  • 6
  • 6
  • 3
  • 3
  • 1
  • 1
  • Tagged with
  • 90
  • 45
  • 27
  • 26
  • 21
  • 17
  • 17
  • 16
  • 16
  • 13
  • 11
  • 10
  • 10
  • 9
  • 9
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Vliv výpadku linky a použití alternativních tras na zajištění kvality služeb / Effect of Network Link Failure and Alternative Route Usage on Quality of Service Assurance

Atanasčev, Petr January 2009 (has links)
Information about the differentiated services (DiffServ), the link failure problems and the alternate routes in a DiffServ domain finding are the aims of the master´s thesis to be given. Properties of the differentiated services, the usage of marking techniques in the DiffServ domain are described in the thesis. The concept of the DiffServ domain, its structure and mostly used today routing protocol OSPF are described too. The function model of the DiffServ domain has been created in the simulation environment called Opnet Modeleler on the basis of the obtained knowledge. The link failure and the following link recovery have been simulated in the model and the effects have been analyzed after that.
52

Zajištění QoS v UMTS síti / QoS Assurance in UMTS Network

Fabricius, Marián January 2009 (has links)
Diploma thesis deals with assign and distribution quality of service in mobile UMTS telecommunication networks. The project consists of two parts, theoretical and practical. Theoretical part of the project is focused to familiarize with functionality of the UMTS network with the main aspect at admission mechanism in radio part of the network as well as quality of service assign mechanisms according to service demands within core network of UMTS. Practical part of the project is given to simulation program OPNET Modeler and its capabilities in network design and testing various parameters of UMTS network with implementation quality of service mechanism. As the asset of diploma thesis becomes designed functional prototype of UMTS network with various options for individual settings user equipment as well as fixed mobile networks nodes.
53

Implementace kvality služby v bezdrátových sítích / Implementation of Quality of Service into Wireless Networks

Kaman, Štěpán January 2009 (has links)
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.
54

Simulace a vyhodnocení scénářů nasazení služeb reálného času do sítí UMTS v prostředí Opnet Modeler / Simulation and evaluation of scenarios running real-time UMTS services in Opnet Modeler environment

Klimeš, Roman January 2009 (has links)
This work deals with the Universal Mobile Telecommunications System problems. It researches the parameters of influencing the UMTS Terrestrial Radio Access Network behaviour where is the Quality of Services support necessary. The aim of this master’s thesis is the simulation and evaluation of scenarios running real-time UMTS services in Opnet Modeler environment. In the first part is the short introduction to this technology problem. The requirements and the aims, the frequency plan, the network architecture and the Quality of Services support in UMTS are described. Creating the mobile network in the OPNET Modeler environment, configuration of the particular elements with the correct functionality and finally the parameters configuration for the Quality of Service at all workstations was the practical part of this work. At last phase was needed to compare the final statistics of the model without QoS support and the model with QoS support. I verified my knowledge in the OPNET Modeler program and the expected simulation results were confirmed. The final part of the thesis was creating the laboratory problem on the basis experience gained.
55

Modelování pokročilých funkcí technologie 802.11e v prostředí OPENT Modeler / Modelling of advanced 802.11e technology features in OPNET Modeler environment

Šeliga, Michal January 2009 (has links)
This master thesis includes a short review of the structure of WLAN (Wireless Local Area Network) technologies 802.11a/b/g, the description of their physical interface and the description of the basic medium access control mechanisms implementing the PCF (Point Coordination Function) and DCF (Distributed Coordination Function) methods. I mainly focused on the detailed evaluation the new 802.11e standard which was designed to efficiently support real-time services in wireless environment. To provide QoS (Quality of Service) support, this standard specifies the EDCA (Ehanced Distributed Channel Access) and HCF (Hybrid Coordination Function) medium access control methods for the shared wireless environment. The next chapter of my work is devoted to the verification of the theoretical results in OPNET Modeler simulation environment. I studied in details the WLAN model available in OPNET Modeler, the effect of data-flow classification into separate categories and the configuration of several access method parameters. Next, I created my own WLAN model according to the 802.11e standard. This model contains four applications two of them with real-time requirements. The model is divided into several scenarios, each focusing on different aspects of wireless network technologies like QoS support and it´s dependency on the number of clients, mobility of wireless terminals and comparison of the 802.11a/b/g and the 802.11e technology.
56

Mobile IPv6 v prostředí OPNET Modeler / Mobile IPv6 in OPNET Modeler

Žáček, Martin January 2010 (has links)
Master’s thesis includes knowledges about mobility support in IPv4 networks and studies abilities for mobility support in IPv6 networks. Describes protocols for mobility support, their functions and topologies like MIPv6 (RFC 3775), FMIPv6 (RFC 5568), HMIPv6 (RFC 5380) and F-HMIPv6. The thesis contains a design of the simulation MIPv6 in the OPNET Modeler program and the measured results are explained. There are analysis of source code for mobility support in MIPv6 too, which were used for design a new protocol according to FMIPv6 in the OPNET. The following parts of the proposal have been successfully resolved. The link-layer events detection, which triggers FMIPv6 protocol and implementation of two new types of messages, RtSolPr and PrRtAdv. Knowledges from this thesis could be used for next development of FMIPv6 in the OPNET. But could be used for generaly development new protocols working at network-layer too.
57

Analýza přenosu dat v konvergované síti / Analysis of data transport in converged network

Menšík, David January 2011 (has links)
This thesis deals with data transmission applications in the converged network, focusing on the WiFi network IEEE 802.11. The theoretical part describes the cause and nature of converged networks. One chapter is devoted to a description of IEEE 802.11, which is next to different standards and options described architecture, coordination and access network QoS solution to that standard. The research is based on custom design converged networks, and WiFi elements in the environment of graphic simulation software OPNET Modeler. In the proposed network was also simulated the operation of services such as voice, video conferencing, FTP and HTTP streaming. Results of simulation data traffic in the network are then analyzed. At the Conclusion of the thesis, is in OPNET Modeller program created the role of laboratory. The essence here is the comparison of operating a converged network, with and without quality support services.
58

Analýza modelů směrovacích protokolů OLSR a AODV pro MANET sítě v prostředí OPNET Modeler / Analysis of MANET Routing Protocols OLSR and AODV in OPNET Modeler Simulation Environment

Machata, Tomáš January 2011 (has links)
The thesis deals with MANET networks and it focuses on the routing process. Most attention is paid to the routing protocols AODV and OLSR. These protocols are described in the detail. The aim of the thesis is to create a simulation model of MANET network in OPNET Modeler environment. In this model the AODV protocol is configured. In order to achieve improved characteristics of the network traffic the routing protocol parameters are optimized. Furthermore the process model of AODV protocol in this environment is studied and extended by a new type of message, which allows a transfer of current transmission speed of MANET station network interface. Current transmission rate of stations is retrieved from the statistics. Every station periodically sends a message to neighboring nodes. The node stores the information into the file when a new message arrives.
59

Modelování bezdrátového přenosového kanálu v simulačním prostředí OPNET Modeler / Modelling the wireless transmission channel in OPNET Modeler simulation environment

Spiglazova, Světlana January 2012 (has links)
This diploma thesis deals with modeling wireless transmission in simulation environment OPNET Modeler. In theoretical part, there is described the very substance of spreading the signal via electromagnetic wave including impact of the surroundings that affects the spreading. These impacts have an influence on described selected parameters of wireless transmission of the signal characterizing its quality. Furthermore, there is described the OPNET Modeler setting, which allows designing the wireless transmission and by means of simulation verifies its functionality and acquires it is parameters. The transmission of the signal from transmitter to receiver itself is divided to individual steps, which are described in detail considering the implementation in aforementioned environment. In practical part, there is configured the basic model of wireless network and also executed series of simulations with different variants of commonly adjustable basic parameters of the transmission, as signal modulation, antenna types and network topology. Additionally, attention is turned to the stages of transmission itself, philosophy of their cooperation based on sharing the information via data units called TDA and their implementation in source code of the C++ language called transmission models. Based on these foundations is beyond beforehand defined created new user TDA and by means of simulation verified its correct implementation within packet switching. Values of the selected including user TDA are written in the window of simulation console with the help of the C++ language. Acquired results of the simulations are analyzed and documented in the conclusion. Source codes are available in the diploma thesis appendix.
60

Laboratorní úlohy v prostředí OPNET pro předmět Komunikační technologie / Laboratory exercises in OPNET environmentfor Communication technolgies course

Kasper, Robin January 2012 (has links)
This master’s thesis deals with the design of laboratory exercises for the Communication Technologies course that is included in the second year of bachelor’s degree in Teleinformatics. This course represents first introduction of students with network protocols and technologies, therefore, the thesis deals with just the basic physical technologies, routing protocols and transport layer protocols. The introductory part of the thesis is devoted to theoretical knowledge to particular tasks. For the design of laboratory exercises is used OPNET environment, concretely its unpaid version IT Guru Academic Edition 9.1. The first task is focused on the differences in two basic transport protocols Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). The second task is orientated on the differences in the transmission network parameters using wireless networks and Ethernet technologies. In the third task the routing protocols Routing Information Protocol (RIP) a Open Shortest Path First (OSPF) are compared. These are protocols of a group Interior Gateway Protocol (IGP) that are characterized by the usage within a single autonomous system. The last exercise is aimed at Asynchronous Transfer Mode (ATM) and Frame Relay technologies, which are technologies used mainly in networks Wide Area Network (WAN). All devised exercises are accompanied by detailed instructions for students including supplementary questions and tasks leading to individual work and reflection. The thesis includes model solutions to these four exercises and CD where are inserted all programs source codes.

Page generated in 0.23 seconds