The Optical Transport Manager performs cross-correlation between the PDH and SONET/SDH domains to determine when alarms in one network domain are caused by problems in another.
Managed objects, for the most part, are populated to either the domain: SDH/SONET for high-order objects or PDH domain for low-order objects. PDH to SONET/SDH cross-domain correlation is made possible by sharing the HighOrder_Trail object in both domains.
HighOrder_Trail has the same class name and instance name in both PDH and SONET/SDH domains. However, the trails in the PDH domain will not have any associated CTPs (that is, a-end, z-end, and CTPsInRoute). The PDH objects will also not have any layering to the SONET/SDH physical objects.
HighOrder_Trail has a one-to-many relationship to the LowOrderCircuits in the PDH domain.