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From the smallest microcomputer to the largest mainframe computer, data communication capabilities are and will be a major factor in the success and usefulness of the computer systems. The need for larger systems to process data created on the small computers, the need to move subsets of data to small computers access larger computers for other capabilities, and the need for growth in hardware capability are all major reasons that data communication is so important to today's technology.As data communication is the backbone of today's technology, it will play a leading role in governing the changes in the technology of the future. Hence the knowledge of data communication becomes a very important aspect.In this thesis emphasis has been given to simulate the lower layers of communication protocols using Ada as the base language. The language Ada is chosen because of it's capability of providing parallel processing, which is an inherent property of the data communication. Ada is a complex, general purpose programming language that provides an excellent concurrent programing facility called task, that is based on rendezvous concept.Simulation is an excellent way to teach & understand concepts, which otherwise becomes infeasible to understand. Now a days more and more communication details is embedded in the hardware, and hence what is going inside the computer, to provide communication between two computers or just plain data communication, is becoming transparent to the user. However, this does not eliminate the need to know about the functional characteristics of the protocols, which are the rules to provide an effective and reliable communication environment, rather the need to understand protocols is increasing as more and more computer vendors are coming out with their own products. Thanks to the ISO (International Standard Organization), which has come with the standard for the Computer to Computer Communication, but still protocol analysis and design will play a very important role. The field of protocol conversion has grown tremendously in order to provide communication across heterogeneous systems using message communication will to the field of protocol which now a days is an different protocols.Here in this study, communication backbone is simulated in Ada using its concurrent processing capabilities and it is tried to show how a data or aMessage communication will actually take place. This study can serve as a blue print to improve this in order to cater to the field of protocol analysis and protocol conversion, which now a days is an important facet of the data communication industry. / Department of Computer Science

Corporate social responsibility (CSR) reporting in annual reports has been investigated by researchers over the past three decades. Because the Internet has significantly eased dissemination of information to global audiences, companies have begun to report CSR-related materials on their corporate websites.The present study is a content analysis examining what CSR principles, processes, and issues are mentioned on corporate websites of top companies in Hong Kong, Japan, Malaysia, and Taiwan. Two coders analyzed seventy-one websites: Hong Kong (19), Japan (19), Taiwan (19), and Malaysia (14). Content on the websites were coded based on definitions and categorizations which were patterned after Maignan and Ralston's 2002 study on CSR reporting. / Department of Journalism

This thesis presents two modern control methods to address the Internet traffic congestion control issues. They are based on a distributed traffic management framework for the fast-growing Internet traffic in which routers are deployed with intelligent or optimal data rate controllers to tackle the traffic mass. The first one is called the IntelRate (Intelligent Rate) controller using the fuzzy logic theory. Unlike other explicit traffic control protocols that have to estimate network parameters (e.g., link latency, bottleneck bandwidth, packet loss rate, or the number of flows), our fuzzy-logic-based explicit controller can measure the router queue size directly. Hence it avoids various potential performance problems arising from parameter estimations while reducing much computation and memory consumption in the routers. The communication QoS (Quality of Service) is assured by the good performances of our scheme such as max-min fairness, low queueing delay and good robustness to network dynamics. Using the Lyapunov’s Direct Method, this controller is proved to be globally asymptotically stable. The other one is called the OFEX (Optimal and Fully EXplicit) controller using convex optimization. This new scheme is able to provide not only optimal bandwidth allocation but also fully explicit congestion signal to sources. It uses the congestion signal from the most congested link, instead of the cumulative signal from a flow path. In this way, it overcomes the drawback of the relatively explicit controllers that bias the multi-bottlenecked users, and significantly improves their convergence speed and throughput performance. Furthermore, the OFEX controller design considers a dynamic model by proposing a remedial measure against the unpredictable bandwidth changes in contention-based multi-access networks (such as shared Ethernet or IEEE 802.11). When compared with the former works/controllers, such a remedy also effectively reduces the instantaneous queue size in a router, and thus significantly improving the queueing delay and packet loss performance. Finally, the applications of these two controllers on wireless local area networks have been investigated. Their design guidelines/limits are also provided based on our experiences.

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Most rural areas of developing countries are faced with problems like shortage of doctors in hospitals, illiteracy and poor power supply. Because of these issues, Information and Communication Technology (ICT) is often sees as a useful solution for these areas. Unfortunately, the social environment is often ignored. This leads to inappropriate systems being developed for these areas. The aims of this thesis were firstly, to learn how a communication system can be built for a rural telehealth environment in a developing country, secondly to learn how users can be supported to use such a system.

A Hybrid Meshnet LAN, a new local area network architecture, has been proposed by Dr. Cheoul-Shin Kang and Dr. James Herzog. It provides for distributed control hybrid architecture which is good for effective load sharing under various local area network environments. Hybrid Meshnet has a dual channel structure, a token ring and a collection of full-duplex data links. The multiple high-speed transmissions, private and secure communications and large volume of data transmission capability are some of the features of Hybrid Meshnet. The design features necessary to implement the network interface unit (NIU) for the Hybrid Meshnet are presented. The unit is a multiprocessor system with each processor having a RISC-like architecture. Various asynchronous activities are distributed among the three processors resulting in a balanced network interface unit. Except for the time critical and non-varying functions, all the functionalities of the unit are programmable. The hybrid meshnet protocol is still in the development stage. The programmable unit will accommodate the changes in the protocol. The network interface unit will be compatible with most of the host computer systems. The study is one step forward in the direction of Hybrid Meshnet Local Area Network's implementation. / Graduation date: 1993

Using the approach of Coloured Petri nets (CPNs) and automata theory, this thesis shows how to formalise the service provided by the Transmission Control Protocol (TCP) and verify TCP Connection Management, an essential part of TCP. Most of the previous work on modelling and analysing TCP Connection Management is based on early versions of TCP, which are different from the current TCP specification. Also the scope is mainly confined to the connection establishment procedure, while the release procedure is either simplified or omitted from investigation. This thesis extends prior work by verifying a detailed model of TCP Connection Management. In defining the TCP service, the set of service primitives and their sequencing constraints are specified at each service access point. / Thesis (PhDComputerSystemsEng)--University of South Australia, 2004.

The Resource Reservation Protocol (RSVP) is one of the proposals of the Internet Engineering Task Force (IETF) for conveying Quality of Service (QoS) related information in the form of resource reservations along the communication path. The RSVP specification (i.e. Request for Comments 2205) provides a narrative description of the protocol without any use of formal techniques. -- abstract. / Thesis (PhD)--University of South Australia, 2003.