Performance study of voice over frame relay : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Information Engineering, Massey University, Albany, New Zealand

Frame Relay (FR) represents an important paradigm shift in modern telecommunication. This technology is beginning to evolve from data only application to broad spectrum of multimedia users and potential to provide end users with cost effective transport of voice traffic for intra office communication. In this project the recent development in voice communication over Frame relay is investigated. Simulations were carried out using OPNET, a powerful simulation software. Following the simulation model, a practical design of the LAN-to-LAN connectivity experiment was also done in the Net Lab. From the results of the simulation, Performance measures such as delay, jitter, and throughput are reported. It is evident from the results that real-time voice or video across a frame relay network can provide acceptable performance

Supporting real time video over ATM networks

Includes bibliographical references.In this project, we propose and evaluate an approach to delimit and tag such independent video slice at the ATM layer for early discard. This involves the use of a tag cell differentiated from the rest of the data by its PTI value and a modified tag switch to facilitate the selective discarding of affected cells within each video slice as opposed to dropping of cells at random from multiple video frames

Traffic Profiles and Performance Modelling of Heterogeneous Networks

This thesis considers the analysis and study of short and long-term traffic patterns of heterogeneous networks. A large number of traffic profiles from different locations and network environments have been determined. The result of the analysis of these patterns has led to a new parameter, namely the 'application signature'. It was found that these signatures manifest themselves in various granularities over time, and are usually unique to an application, permanent virtual circuit (PVC), user or service. The differentiation of the application signatures into different categories creates a foundation for short and long-term management of networks. The thesis therefore looks from the micro and macro perspective on traffic management, covering both aspects. The long-term traffic patterns have been used to develop a novel methodology for network planning and design. As the size and complexity of interconnected systems grow steadily, usually covering different time zones, geographical and political areas, a new methodology has been developed as part of this thesis. A part of the methodology is a new overbooking mechanism, which stands in contrast to existing overbooking methods created by companies like Bell Labs. The new overbooking provides companies with cheaper network design and higher average throughput. In addition, new requirements like risk factors have been incorporated into the methodology, which lay historically outside the design process. A large network service provider has implemented the overbooking mechanism into their network planning process, enabling practical evaluation. The other aspect of the thesis looks at short-term traffic patterns, to analyse how congestion can be controlled. Reoccurring short-term traffic patterns, the application signatures, have been used for this research to develop the "packet train model" further. Through this research a new congestion control mechanism was created to investigate how the application signatures and the "extended packet train model" could be used. To validate the results, a software simulation has been written that executes the proprietary congestion mechanism and the new mechanism for comparison. Application signatures for the TCP/IP protocols have been applied in the simulation and the results are displayed and discussed in the thesis. The findings show the effects that frame relay congestion control mechanisms have on TCP/IP, where the re-sending of segments, buffer allocation, delay and throughput are compared. The results prove that application signatures can be used effectively to enhance existing congestion control mechanisms.AT&T (UK) Ltd, Englan

Flow and congestion control in frame relay networks

This thesis describes the algorithms developed to improve the overload performance of frame relay networks. These algorithms were developed by incorporating a number of congestion control techniques in the existing LAPD protocol (as defined in recommendation CCITT Q.920-Q.921). In addition, the performance analysis of the model is given. Simulation models were developed to evaluate the performance of these networks. A network simulation tool, OPNET, was used for this purpose. The performance of the enhanced model was compared with the existing protocol. A significant improvement was observed in the throughput and delay performance of frame relay networks. The results were obtained by executing extensive simulations and collecting data over a number of simulation runs. The effectiveness of the congestion control techniques was tested by analysing the dynamic performance of the model. These techniques, if implemented in the existing protocol, will ensure the good userperceived network performance at all loads

Integrated dynamic bandwidth allocation and congestion control in satellite frame relay networks

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 100-102).by Chee-Heng Lee.M.S

FR/ASimJava: a federated approach to parallel and distributed network simulation in practice, Journal of Telecommunications and Information Technology, 2006, nr 4

The paper addresses issues associated with the application of federations of parallel/distributed simulators to large scale networks simulation. We discuss two principal paradigms for constructing simulations today. Particular attention is paid to an approach for federating parallel/distributed simulators. We describe the design and performance of frame relay network simulator (FR/ASimJava) implemented based on a Java-based library for distributed simulation – ASimJava. Six practical examples – six networks operating under frame relay – are presented to illustrate the operation of the given software tool. The focus is on the efficiency of presented network simulator

A cross-layer implementation of Ad hoc On-demand Distance Vector routing (AODV) protocol

Mobile Ad hoc Networks (MANETs) are networks which will form the basis for the ubiquitous data access because of their ease of deployment. Due to the dynamic nature of a MANET, routing is one of the most critical elements of MANET. Routing protocols for MANET can be broadly classified as a proactive routing protocol or a reactive routing protocol. In the proactive routing protocols, mobile nodes periodically exchange routing information among themselves. Hence proactive routing protocols generate high overhead messages in the network. On the other hand, reactive routing protocols work on-demand. Thereby generating less number of overhead messages in the network compared to proactive routing protocols. But reactive routing protocols use a global search mechanism called \u27flooding\u27 during the route discovery process. \u27Flooding\u27 generates a huge number of overhead messages in the network. Those overhead messages affect the performance of reactive routing protocols in term of network throughput. That kind of performance problem is called \u27scaling\u27 problem. Ad hoc On-demand Distance Vector Routing with Cross-Layer Design (AODV-CL) protocol has been proposed to solve this scaling problem. The AODV routing protocol has been modified to implement AODV-CL protocol. AODV-CL protocol reduces \u27flooding\u27 problem of reactive routing protocols by limiting the number of nodes that should participate in route discovery process based on their status in the network and also avoiding congested area of the network. It is shown that AODV-CL protocol reduces overhead messages by 73% and reduces end-to-end delay per packet by 32% compared to regular AODV protocol. I