Cross-domain correlation is the capability of determining when alarms in one network domain are caused by problems in another. The Optical Transport Manager performs cross-correlation between the WDM and SONET/SDH domains.
Failures in the WDM network cause problems in the SONET/SDH network, and conversely, failures in the SONET/SDH network cause alarms in the WDM network. The Optical Transport Manager correlates alarms in each of the WDM and SONET/SDH domains and identifies which SONET/SDH problems are impacts of underlying WDM problems, and which WDM alarms are explained by SONET/SDH problems.
Cross-domain correlation on page 88 provides more information.