Physical-layer aware design and service provisioning in transparent wavelength-routed networks.

摘要

This dissertation aims to provide insight into understanding how the end-to-end transmission quality influences the bandwidth capacity in transparent DWDM networks, and what can be done to improve the Bit Error Rate (BER) performance by employing intelligent resource allocation algorithms. Incorporating practical transmission impairments into the network and traffic model, this study covers a number of topics, including network design, online service provisioning, and network security issues.; In the network design category, an amplifier placement and gain provisioning algorithm is proposed for DWDM networks with static or dynamic traffic. Results show that this algorithm significantly outperforms uniform placement and gain provisioning schemes in providing targeted BER performance, without incurring more amplifier cost. Also in this category, a virtual loop effect in which signals experience continuous power attenuations due to the implemented dynamic power equalization mechanisms is studied. Design guidelines on how to arrange link gains to prevent virtual loops from forming are provided.; In the service provisioning category, topics of routing, wavelength assignment, and source power management are individually addressed. New algorithms are proposed to enhance the BER-awareness of the entire admission control process. Compared to traditional BER-blind resource allocation algorithms, the proposed algorithms, implemented individually or jointly, can largely reduce the number of blocked calls due to unsatisfactory BER, and improve the effective network capacity.; In the network security category, component vulnerabilities that can be taken advantage of by malicious attackers to conduct service-degrading/disruptive attacks are investigated. Principles and BER impact of a number of novel attacking scenarios are presented, and detailed guidelines are provided on how to enhance the network robustness against these vicious attacks by properly designing and implementing performance monitoring devices.; As diverse as these problems appear to be, they share the common objective of providing network designers and operators with effective means to attain the targeted Quality of Service (QoS). In fact, research attention is picking up nowadays when more and more people begin to realize the practical significance of transmission effects. This study was among the earliest efforts that comprehensively explored these issues.