This DateAndTime value is the timestamp UCS Manager attached to the moment it actually sampled the receive counters for this object. It matters on the live receive-side counter set UCS Manager keeps for one Ethernet endpoint (a blade's vNIC adapter port, an I/O Module uplink, or a fabric-interconnect server port) inside a UCS domain because it is the only field that ties a given set of packet/byte numbers to a specific point in time, which is essential once multiple historical rows exist. Two rows with timeCollected values twelve minutes apart on this interface tell an admin the polling interval that was actually honored, even if the configured interval was five minutes.