This thesis deals with the routing of data traffic to multiple gateways with a network operating system MikroTik RouterOS, which has become widespread in the small firms and home users. It is aimed to describe the problem with using multiple gateways. RouterOS description itself and its core components needed to solve this issue, such as routing, packet marking and quality assuranceservices. It also deals with the description of the particular design and testing. The proposedsolution is verified on the example of a real situation. Finally, the proposed solution is compared to alternative solutions, commonly used in practice.

The diploma thesis "QoS model for Mobile ad hoc network" focuses on the quality of services in MANET (Mobile Ad-hoc) networks. It describes MANET networks and covers the theoretical analysis of routing protocols with QoS (Quality of Service) support. Furthermore, there is processed the creation process of model MANET networks with the routing protocol DSDV (Destination-Sequenced Distance Vector) in the simulation environment NS-3 (Network Simulator 3) and its extension of QoS support. The used QoS model is subsequently modified to improve core operating parameters. The implementation of QoS parameters as well as the improvement of delay and jitter (the delay between selected packets) is verified by the functional simulation.

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.

This work deals with user satisfaction with mobile data service. The main part is devoted to the development of a mobile application that provides testing network parameters to evaluate and use online databases shared with other users. Discussed the possibility of distributing applications among users over its testing and then to the App Store.

This master thesis deals with creating laboratory exercises for students in simulator NS-3, where the IPv4 and IPv6 protocols, unicast and multicast transmission types, quality of services in wireless networks, furthermore protocols TCP and UDP are analyzed. The first section describes the NS-3 network simulator, the Eclipse development environment and the method how to connect them. In the next section protocols IPv4 and IPv6 are presented, the structure of the headers and the technique of fragmentation are described in detail. Based on this a laboratory exercise is created which deals with comparison of protocols IPv4 and IPv6. In the next section the types of transmissions are described, furthermore the multicast transmission type is explained more in detail. In the next practical section the second laboratory exercise is created, which deals with comparison of unicast and multicast transmission types. The subject of the following section is ensuring quality of services in data networks, the EDCA access method is discussed more in detail. In the next section the EDCA access method is implemented in a simulation as a laboratory exercise, in which the impact of the access category of EDCA to different transmission parameters is investigated. The next section deals with protocols TCP and UDP, furthermore with the structure of their headers. In the last section a laboratory exercise is created, in which the properties of the protocols TCP and UDP are compared.

This thesis consists of theoretical and practical parts. The theoretical part contains an analysis of the problems of wireless networkssolutions individual standards and methodologies to ensure quality of service. In the practical part using the OPNET Modeler, a number of different simulation models and their evaluation. It is a model of individual standards, support mobility and interference effects on quality of service.

The doctoral thesis is focused on a research in the area of the quality-of-service support technologies in data networks. The current modern communication networks cannot operate correctly without an effective tool allowing differentiated treatment for various network traffic classes. Looking at the current trends in this area it turns out that the technology of Differentiated services is currently the most widely used mechanism for QoS assurance in data networks. The major part of this doctoral thesis concerns the design of a novel QoS system which offers a solution for one of the main problems of DiffServ technology. This disadvantage lies in the missing cooperation between the end station and edge node of the DiffServ domain. To overcome this limitation the system proposed introduces an improvement which enables the user application to actively participate in the resource reservation process by direct configuration of the DSCP value in the IP header of its own packets. This functionality is based on the identification of DiffServ configuration parameters available in the edge router. To retrieve the information required from network component the well-known SNMP protocol has been chosen, which has direct access to the components’s configuration stored in the MIB database. On the basis of this theoretical proposal several simulation scenarios have been created and analysed. The results show that the system designed presents an efficient solution for the mentioned problem of DiffServ. They also give good assumptions for the successful implementation of this system into a real environment.

The thesis focuses on the optical access networks and deals with the issue of transmission parameters of the physical layer, their negative impact on the quality of the services parameters and the possibilities of reducing their effect using the polarization multiplexing. The first and second chapter describe the theoretical background necessary for understanding the subsequent parts. The third chapter contains the practical part of the thesis. At first the optical routes in the Czech Republic in terms of polarization mode dispersion, which is together with insertion loss the main limiting parameter of high-speed optical networks, are evaluated. In the following part the measuring of the temperature changes effects on the polarization mode dispersion of the passive components and the effect of temperature changes to the polarization multiplexed signal are evaluated. To double the bandwidth and reduce the influence of polarization mode dispersion on the quality of services, the two simulation models of optical access networks using polarization multiplexing were carried out. These theoretical outputs were verified by the practical measurements in the laboratory and subsequently on the real optical route. Finally, a draft of the broadband optical access network based on wavelength and polarization multiplexing was designed based on obtained knowledge.

Diese Diplomarbeit beschäftigt sich mit der "schleichenden Abschaltung" begrenzter Netzzugänge bei Überschreitung eines vorgegebenen Datenvolumens und der Anwendung dieser Technologie im Chemnitzer Studentennetz. Nutzer, die bestimmte Transfervolumina überschreiten, werden schrittweise einer immer schlechter bewerteten Verkehrsklasse zugeordnet, wo ihnen weniger Bandbreite zur Verfügung steht. Dazu werden die Möglichkeiten, die der Linux-Kern hinsichtlich Quality of Service bietet, genutzt.

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur Rechnernetze und verteilte Systeme der Fakultaet fuer Informatik der TU Chemnitz. Der Dynamic Traffic Shaper erlaubt ein dynamisches Bandbreiten-Management von begrenzten Netzzugängen unter Zuhilfenahme der Quality-of-Service-Möglichkeiten des Linux-Kerns. Er wird typischerweise auf einem Router, der das gemanagete lokale Netz mit dem Internet verbindet, eingesetzt. Nutzer dieses Netzes werden anhand ihrer Transfervolumina für eine gewisse Zeit in verschiedene Nutzergruppen mit unterschiedlichen Bandbreiten eingeordnet. Damit soll sichergestellt werden, dass über einen bestimmten Zeitraum nur ein festgelegtes Datenvolumen verursacht werden kann. In diesem Vortrag werden die aktuellen Entwicklungen beim Einsatz im Chemnitzer Studentennetz aufgezeigt.