Survivable virtual concatenation for data over SONET/SDH in optical transport networks

摘要

Next-generation SONET/SDH technologies-namely, generic framing procedure, virtual concatenation, and link-capacity-adjustment scheme-enable network operators to provide integrated data and voice services over their legacy SONET/SDH infrastructure to generate new revenue. An important open research problem on data over SONET/SDH (DoS) is survivability: SONET automatic protection switching is too resource inefficient for data services, and the protection mechanisms of data networks are too slow for mission-critical applications. We propose two approaches for provisioning survivable DoS connections. Our approaches exploit the tradeoff between resource overbuild and fault-recovery time while utilizing the inverse-multiplexing capability of virtual concatenation to increase backup sharing. Our results show that one approach achieves low resource overbuild and much faster fault recovery than that of data networks, and the other approach achieves fast fault recovery comparable to SONET 50-ms protection (for typical U.S. backbone networks) while still achieving modest backup sharing. We further investigate the tradeoff between network blocking performance and network control and management complexity resulting from the number of paths M a connection can be inversely multiplexed onto: larger M leads to more freedom in routing and better network performance but increases network control and management complexity. Our results indicate that the network blocking performance for small values of M (e.g., M=2 for some representative backbone network topologies) is almost as good as the case in which M is infinity.