Research On Protection Algorithms For Survivability In Meshed WDM Networks

WITH the explosive increase in Internet traffic and the tremendous demand in bandwidth and capacity, the technique of Wavelength Division Multiplexing (WDM) will become the core of the next generation backbone networks. The concept of constructing the optical layer or virtual topology over the physical networks through the technique of WDM and wavelength routing will become the important transmission method in the future backbone networks. Since each wavelength channel has the transmission rate over several gigabits per second, the failures of fiber links or nodes may lead a lot of services to be blocked. Therefore, the survivability has emerged as one of the important issues in the design of WDM optical networks. The strategy of survivability mainly includes protection and restoration. In protection, the backup resources will be pre-assigned to against the future unknown failures. In restoration, the backup resources are not be pre-assigned; after failures occurring, the backup resources will be assigned dynamically according to the current network state. Since the protection technique has faster failures recovery time, many researches are based on the protection. With the concept of protection, this dissertation investigates the protection design in WDM mesh networks, including: the double-link failures, the SRLG constraints, the differentiated reliability, the mixed shared protection model and multiple failures problem.Previous works mostly investigated the single-link failure problem in WDM mesh networks. With the size of networks keeping enlarge, the double-link failures problem must be considered. Therefore, in chapter 2, the authors study the protection design for double-link failures from five perspectives. (1) Based on the path protection model, the authors propose a new algorithm called NPSP (New Path Shared Protection), which can dynamically adjust the link-cost according the current network state and improve the performance of load-balancing and resources sharing degree. (2) Based on the previous shared link protection algorithm called LSP (Link Shared Protection), the authors propose a new link protection algorithm called TBP (Two Backup Paths) and a modified link protection algorithm OBP (One Backup Path), which both have better performance than the previous LSP. (3) Considering that the LSP has fast protection switching time...