The aim of this thesis was to get acquainted with the technology of routing data in a computer network. Thesis described in the theoretical level properties of current and past routing protocols and their use in information systems. Based on the acquired knowledge was created a simulation model of network communication in programming environment OPNET Modeler. This model analyzes the received parameters of the current protocols and their subsequent implementation in the real transmission technology using operating system Debian Linux. Finally, the transfer parameters are discussed between the simulation model and real transfer technology.

The master thesis „IP traffic performance“ is focused on traffic testing in IP networks. Theoretical section explains routing issue in an autonomous system. This work contains a detailed description of OSPF protocol. This work also deals with behavior of a link failure. There are described mechanisms that are used to link failure detection and subsequent traffic rerouting. The next section describes mechanisms to ensure quality of service. In master thesis are explained InterServ and DiffServ mechanisms. A large part is devoted to DiffServ mechanism that ensures distinction of data flows and classification packets into different classes. The routers than can process the individual data streams with different priorities. The practical section includes the design of experimental network and creation of simulation in Opnet Modeler. By using several scenarios are compared the characteristics of routing protocols and impact of QoS on the transmission characteristics of the network. Part of practical section is the improvement of OSPF protocol by adding a new metric and implementing a new metric in software suite Quagga.

The aim of master's thesis was to demonstrate chosen PON network in simulation software OPNET Modeler. The work deals with passive optical networks. In particular, solutions that are based on the transmission of Ethernet frames. EPON and 10GEPON standards are described in theoretical section. EPON Standard was introduced already in 2004. Newer 10GEOPN is back compatible, which is ideal as a suitable solution for modern network with a high data rates demands. The practical part describes process of developing network nodes for passive optical network. EPON model was developed in simulation tool, that demonstrates basic features of the standard IEEE 802.3ah. The simulation results are demonstrated in last section.

This thesis deals with the design of three labs in the simulation environment OPNET IT Guru. The first lab demonstrates the differences between the RM OSI transport layer protocols - TCP and UDP. The second lab discusses the role of ICMP protocol and its most famous feature - PING. The third lab is devoted to Application Characterization Environment (ACE) module, which is included in OPNET IT Guru. Theoretical background is provided for all of the mentioned topics. All designed labs can be used to teach at the Faculty of Electrical Engineering and Communication of BUT on subjects dealing with network technologies.

This thesis "Processing statistics generator IxChariot network traffic in an environmentsimulator OPNET Modeler" is focused on collaboration solution simulation tool OPNET Modeler with IxChariot traffic generator and the principle of their connection. The goal is to display the statistics generated in IxChariot software by OPNET Modeler. In this thesis is described procedure of settings inside simulation environment OPNET modeler which are necessary for correct functionality of simulation.

The aim of this paper is to apprise ourselves with communication in NG-PON2 standard. The first chapter describes optical networks. The second chapter deals with description of NG-PON2 standard and detailed description of downstream and upstream frame. Methods of grant allocation are described at the end of the theoretical section of this paper. Own entities were created in the practical part of this paper and they were used to simulate static and dynamic grant allocation. Designed entities and simulation results were compared with the real network behaviour at the end of the practical part. Designed entities were also used to design a lab exercise in the attachment.

The Internet and intranets are viewed as capable of supplying "Anything, Anywhere, Anytime" and e-commerce, e-government, e-community, and military C4I are now deploying many and varied applications to serve their needs. Network management is currently centralized in operations centers. To assure customer satisfaction with the network performance they typically plan, configure and monitor the network devices to insure an excess of bandwidth, that is overprovision. If this proves uneconomical or if complex and poorly understood interactions of equipment, protocols and application traffic degrade performance creating customer dissatisfaction, another more application-centric, way of managing the network will be needed. This research investigates a new qualitative class of network performance measures derived from the current quantitative metrics known as quality of service (QOS) parameters. The proposed class of qualitative indicators focuses on utilizing current network performance measures (QOS values) to derive abstract quality of experience (QOE) indicators by application class. These measures may provide a more user or application-centric means of assessing network performance even when some individual QOS parameters approach or exceed specified levels. The mathematics of functional analysis suggests treating QOS performance values as a vector, and, by mapping the degradation of the application performance to a characteristic lp-norm curve, a qualitative QOE value (good/poor) can be calculated for each application class. A similar procedure could calculate a QOE node value (satisfactory/unsatisfactory) to represent the service level of the switch or router for the current mix of application traffic. To demonstrate the utility of this approach a discrete event simulation (DES) test-bed, in the OPNET telecommunications simulation environment, was created modeling the topology and traffic of three semi-autonomous networks connected by a backbone. Scenarios, designed to degrade performance by under-provisioning links or nodes, are run to evaluate QOE for an access network. The application classes and traffic load are held constant. Future research would include refinement of the mathematics, many additional simulations and scenarios varying other independent variables. Finally collaboration with researchers in areas as diverse as human computer interaction (HCI), software engineering, teletraffic engineering, and network management will enhance the concepts modeled.

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.

Network coding is a technique used to increase the capacity of a network by combining messages sent over the network. The combined messages could be separated by using sufficient original messages which were used to combine the messages. Network coding can be implemented in different layers of the 051 stack, but to date a complete comparison between different implementations of network coding has not been done. The goal of this dissertation is to implement a wireless node model with network coding in the MAC layer and evaluate the performance characteristics of reference networks that implement the new node model. This will serve as the first step of a greater goal, namely finding the most favourable position in the 051 stack to implement network coding. The characteristics of the different implementations of network coding are presented in this dissertation. Simulations were done in OPNET® to find further attributes concerning the implementation of network coding in the MAC layer. The simulation process used is presented and explained, and the results from the simulations are analysed. Network coding in the simulations was implemented opportunistically. The results show that the more often different nodes send frames to the coding node, the better network coding performs. The work contributes to finding the best layer for implementing network coding for its increased throughput. A benchmark network was created so that network coding could be implemented in all the layers of the 051 stack, and then be compared to each other. An implementation of network coding in the MAC layer was simulated and analyzed. We conclude that, because there are so many different purposes for which networks are used, a single instance of network coding is unlikely to be similarly beneficial to all purposes. There still remains work to find the most favourable position for network coding in the 051 stack for all the different types of network coding. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011

Network coding is a technique used to increase the capacity of a network by combining messages sent over the network. The combined messages could be separated by using sufficient original messages which were used to combine the messages. Network coding can be implemented in different layers of the 051 stack, but to date a complete comparison between different implementations of network coding has not been done. The goal of this dissertation is to implement a wireless node model with network coding in the MAC layer and evaluate the performance characteristics of reference networks that implement the new node model. This will serve as the first step of a greater goal, namely finding the most favourable position in the 051 stack to implement network coding. The characteristics of the different implementations of network coding are presented in this dissertation. Simulations were done in OPNET® to find further attributes concerning the implementation of network coding in the MAC layer. The simulation process used is presented and explained, and the results from the simulations are analysed. Network coding in the simulations was implemented opportunistically. The results show that the more often different nodes send frames to the coding node, the better network coding performs. The work contributes to finding the best layer for implementing network coding for its increased throughput. A benchmark network was created so that network coding could be implemented in all the layers of the 051 stack, and then be compared to each other. An implementation of network coding in the MAC layer was simulated and analyzed. We conclude that, because there are so many different purposes for which networks are used, a single instance of network coding is unlikely to be similarly beneficial to all purposes. There still remains work to find the most favourable position for network coding in the 051 stack for all the different types of network coding. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011