The real DESCRIPTION field here is just the auto-generated stub "Cisco UCS fabric:FcoeSanEp:udldOperState managed object property", so it carries no real prose -- but the property name and its CucsFabricUdldOperState type tell you what it holds: It holds the operational state of UniDirectional Link Detection (UDLD) on this FCoE SAN uplink port. UDLD exists specifically to catch a mis-wired fiber pair where one direction of the link is receiving traffic and looks up while the other direction is dead -- a fault that plain link-state monitoring on this FCoE SAN uplink port would otherwise miss entirely, so this field is the early-warning signal for that exact failure mode. A healthy bidirectional link on this FCoE SAN uplink port shows udldOperState "bidirectional"; a value like "unidirectional" would mean UDLD has caught exactly the one-way-fiber fault it is designed to detect.