This article first presents a broad summary of the fault management mechanisms involved in deploying a survivable optical mesh network, employing optical crossconnects. Various protection and restoration schemes, primary and backup route computation methods, sharability optimization, and dynamic restoration have been analyzed. Different parameters that can measure the quality of service provided by a wavelength-division multiplexing (WDM) mesh network to upper protocol layers such as service availability, service reliability, restoration time, and service restorability have been described. These concepts, the factors that affect them, and how to improve them have also been analyzed. In particular, a framework for cost-effective availability-aware connection provisioning to provide differentiated services in WDM mesh networks has been presented. Through the framework, the more realistic scenario of multiple near-simultaneous failures can be handled. In addition, the emerging problem of protecting low-speed connections of different bandwidth granularities has also been examined.