A Multistate Multipath Provisioning Scheme for Differentiated Failures in Telecom Mesh Networks

Telecommunication networks spanning large areas are subject to various failures, such as natural disasters, operation errors, and malicious attacks. Disaster failures (DFs) are those, which can lead to a large-area malfunction and degrade the performance of a backbone telecom mesh network. A survivable network provisioning scheme that can recognize and address multiple levels of network failures, including DFs, is desirable for the future Internet. We study the characteristics of multiple failures in telecom mesh networks, such as optical wavelength-division-multiplexed (WDM) networks. In particular, we devise a novel provisioning scheme for telecom mesh networks, which can efficiently exploit the network connectivity using multiple paths. Three provisioning states are defined, in response to single-link failure (SF), multiple-link failure (MF), and DF. We integrate the conventional primary-backup method with reprovisioning and degraded service (i.e., a reduced level of service versus no service at all) into a state-transition model to handle different levels of failures. A predefined level of service is guaranteed for premium customers even if the service cannot be fully recovered. Multinode failures within the same shared risk group (SRG) and failures on destination node are also considered in our study. Our results show that: 1) connection-dropping probability due to a node failure can be significantly reduced with a small extra cost in SF protection; 2) for single-node failure, our algorithm achieves better performance than the shortest vertex-disjoint algorithm; and 3) remote-site data replication is effective to protect against destination-node failures.