| The Internet has grown very successfully for more than three decades, offering only one service type: best-effort service. As initially designed, it has been successful in providing reliability and resilience in data transmission which has included changes in both network resource and topology. However, this ubiquitous data network has recently faced new network applications which demand more stringent and sophisticated services. Multimedia applications are the newly emerging network traffic. As the significance of these applications increases, the nature of the Internet has been challenged and has necessarily changed. Currently, researchers are focusing on enhancing Internet services by embedding new technologies to provide “Quality-of-Service” support.; Regarding the concept of QoS support, this dissertation focuses on two substantial issues: fault-tolerant QoS support and deployment of QoS-enabled network systems. Previous QoS studies have raised issues regarding efficient network resource management, algorithms for selecting feasible network paths, classifying network traffic, and other related areas. In conjunction with these issues, we place special emphasis upon the concept of “reliable” QoS support. The importance of the reliability issue becomes crucial when the multimedia applications are mission-critical such as time-critical experiments in virtual collaboration, remote surgical procedures, and video conferencing for motherland security. Thus, provisioning QoS must signify “reliable QoS support.” This new aspect stems from conventional QoS approaches and augments those approaches with provisioning multiple QoS paths as planned redundancy. In addition, these QoS support mechanisms must be practically feasible to be deployed in real network systems. This dissertation also introduces a network system which consists of the proposed algorithms for fault-tolerant QoS support and shows the practical benefits of the relevant protocols developed. In order to achieve a feasible and efficient implementation of the QoS system, we have analyzed applicable Internet architecture and protocol issues.; We will first address the fundamental issues about QoS support in the Internet. Then, the issue of reliability will be discussed with newly revised QoS routing algorithms. Additional attempts and proposals for adapting the proposed QoS schemes to the Internet will be introduced. Finally, the QoS network testbed will be presented with the results of various practical experiments. |
