It denotes the traceability of the time or frequency distributed by the grandmaster clock. This value is used by the BMC algorithm to select the best master clock. This should be initialized after initializing ptpClockSlaveOnly. If ptpClockSlaveOnly is TRUE, then this value should be 255. For clock class 6 or 13 it should represent the clock class of the clock UPON exiting the Initialializing state.