This value records the discovery status of this satellite (IOM/FEX) connection as seen from the Fabric Interconnect, i.e. how far UCS Manager's automatic chassis-discovery process has progressed for this specific link. It matters on the same internal chassis backplane link, but the record kept on the Fabric Interconnect (switch) side rather than the IOM/server side because a chassis that's physically cabled but stuck at an early discovery state won't yet appear as usable, and this field is exactly where that stuck state shows up. A discovery value showing an incomplete state on this link's fabric-interconnect side well after cabling was completed is the field an admin checks before deciding whether to manually re-acknowledge the chassis.