Design and analysis of survivable telecom mesh networks

Optical fiber technology employing wavelength-division multiplexing (WDM) has been and continues to be investigated and commercially deployed to meet bandwidth-intensive application demands. A fiber cut may result in huge data and revenue loss. Therefore, it is very desirable to design a survivable telecommunications network. This dissertation investigates design and modeling issues of survivable telecom mesh networks. This dissertation first explores the problem of providing availability guarantees for differentiated services. We present a mathematical model for availabilities of connections with shared-path protection by applying the link-vector technique. Based on the model, we propose an efficient provisioning algorithm to provide differentiated services, either no protection, shared-path protection, or dedicated-path protection to dynamic connection requests in a network. The strategy jointly considers both availability satisfaction and resource optimization. Next, we investigate the problem of backup-bandwidth reprovisioning after network-state updates due to connection arrivals and departures as well as failure occurrences and repairs. Rearranging backup bandwidth periodically for existing connections upon network-state updates helps to reduce resource redundancy and improve the blocking performance. We propose both Integer Linear Program (ILP) formulation and heuristic algorithms. We investigate the effects of different reprovisioning periods and some additional dimensions of backup-bandwidth reprovisioning. We also study the effects of multiple backup paths and link sharing among primary and backup paths for availability-guaranteed and service-differentiated provisioning. We present an availability-analysis model for connections with 1+N (N≥1) dedicated-path protection scheme with k ( k≥1) shared links among primary and backup paths. Based on the model, we propose a provisioning algorithm to explore the effect of link sharing among one primary and N backup paths such that good capacity utilization can be achieved. We develop an accumulated-downtime-aware restoration algorithm for connection recovery against link failures. Upon a link failure occurrence, a faulty connection is switched to its pre-assigned backup route or an alternate restoration path (if resources are available), only when its accumulated downtime plus the link repair time will violate its service-level agreement (SLA) requirement. This dissertation makes important contributions by introducing and studying novel models, algorithms and architectures that will help to improve survivability of next-generation telecom networks.