Spare capacity reprovisioning for high availability shared backup path protection connections

Shared backup path protection (SBPP) has been widely studied in the Generalized MPLS (GMPLS) networks due to its efficient spare capacity sharing as well as simplicity and flexibility in service provisioning. This paper presents a novel availability evaluation strategy for the end-to-end (E2E) availability of an SBPP connection by considering up to two simultaneous failures, where the sequence of failures in a failure pattern is considered. To minimize the redundancy while meeting the E2E availability requirement, partial restoration is defined and embedded in the developed model, by which a novel parameter, called a protection level, is manipulated. Based on the proposed availability model, two Linear Program (LP) formulations are introduced, which aim to perform spare capacity reprovisioning along each link for dynamic allocation of SBPP connections under either failure-dependent or failure-independent policies. Extensive simulations are conducted to validate the proposed availability model and demonstrate the effectiveness of the spare capacity reprovisioning architecture. The proposed availability-aware spare capacity reprovisioning approaches are then implemented on top of a well known survivable routing scheme - Successive Survivable Routing (SSR), where the spare capacity saving ratio is taken as the performance measure. We will show that the proposed spare capacity reprovisioning framework is an effective approach for achieving the GMPLS-based recovery in packet-switched networks.