Resource Optimization And Service Quality In WDM Optical Networks

Backbone transport networks are evolving into a two-layer architecture of IP overWDM networks. In the WDM layer, circuit-switching-based intelligent optical net-works are/will be widely deployed, with the optical burst switching envisioned as apromising switching paradigm for future WDM networks. To catch up with this trend,this dissertation studies from the resource optimization perspective and the service per-spective two key issues during the architecture migration, i.e., survivability of opticalcircuit switching networks and routing in optical burst switching networks.In recovery-time-di?erentiated optical networks employing dedicated path pro-tection and shared path protection, resource-e?cient provisioning scheme is proposedwithout deteriorating the recovery time of either protection type (in the predominantsingle link failure scenarios). Numerical results show that compared with traditionalscheme, resource-e?cient provisioning scheme reduces the blocking probability ofboth protection types as well as the overall resource overbuild of the network.Next, backup path reoptimization scheme is applied to the network engineering(NE) problems in shared-path-protected optical networks. For scheduled tra?c, peri-odic rearrangement of protection paths reduces the average spare capacity consumptionof the network. For semi-dynamic tra?c, blocking-di?erentiated lightpath provision-ing between two classes of connection requests is achieved by introducing the proposedpost path calculation process for high-class requests, during which the ?exibility ofrerouting backup paths is considered.As a first attempt to address the problem of"how does backup path reprovision-ing a?ect connection availability?", this dissertation quantitatively evaluates the con-nection availability in a network employing backup path reprovisioning. Numericalresults show that shared path protection with startup-failure-driven backup path re-provisioning reduces connection unavailability. Moreover, results show that arbitraryfailure-arrival-and-failure-repair-events-driven backup path reprovisioning is an attrac- tive approach for non-revertive operations of shared-path-protected connections whensucient free wavelengths are available in the networks.In IP over all-optical transparent networks, a new survivable mapping problemis proposed that the physical-layer failure-localization potential is maximized in find-ing the survivable mapped lightpaths. Numerical results show that accurate or near-accurate failure localizations are achieved with the new survivable mapping design.In oset-time-based loss-di?erentiated optical burst switching networks, a class-aware routing scheme is proposed to reduce the burst loss probability by splitting traf-fic while avoiding the introduction of burst reordering mechanism. Numerical resultsshow that compared with traditional class-oblivious routing, class-aware routing fur-ther reduces the burst loss probability of multiple classes especially when the networkload is light or moderate.