In the classical APLS resilience scenario, the fault recovery mechanism can only be deployed in two ways: either 100% protects traffic in protection switching case, or unprotect traffic in rerouting case. Consequently, the resource consumption is too high for network to afford if the fast recovery mechanism (protection switching) is deployed in the whole network. One of the objectives of our proposed multiclass resilience scheme is to decrease the resource consumption caused by recovery mechanism, while still meeting the needs of resilience requirements for network services. This is achieved by providing the differentiated resilience mechanisms for different services accordingly to meet their respective resilience requirements. Another improvement to the network performance in our proposal is done through offering an optimized routing algorithm for backup path computation in resilience. The algorithm finds optimized explicit routes for both working and backup paths for services with high-level resilience requirements. Through the treatments, Traffic Engineering capability is provided in resilience with the improvement of network resources utilization, and the provisioning of fast fault recovery mechanism for the services with high-level resilience requirements.
