Design procedures and restoration schemes for backbone transport networks: Optimization-based models, heuristic algorithms, and unavailability computations.

摘要

This dissertation presents optimization-based design models and algorithms for reliable backbone transport networks. Due to their efficiency in providing data services and high data rates, dense wavelength-division-multiplexing (DWDM) networks became the technology of choice for these transport networks. DWDM networks achieve these high rates by enabling several wavelengths of light to be transmitted on a single strand of fiber. The first design models introduced in this investigation address various restrictions inherent in DWDM technology including polarization mode dispersion and attenuation requirements. They also provided routing and equipment needed for working paths, but provided no protection. A single fiber cut or an equipment failure can have a severe impact on the working traffic between several nodes. In a network with no protection, recovery from a failure may take several hours. The next set of design models expanded the basic ones to include dedicated protection. That is, every working path has at least one dedicated backup path that can be used when failures occur on the working paths. This strategy is simple to implement and provides high reliability. Unfortunately, it is also the most expensive protection strategy since more than 50% of the hardware is idle most of the time. The final set of design models allow sharing of hardware on the backup paths. Furthermore, approximations are developed to determine reliability of any given origin-destination pair in a DWDM network. Finally, all models and protection schemes are compared based on design costs and reliability in empirical analyses.