The threshold used to declare leftr defects (see clause 11.3.3) expressed in fraction of the NDR. The value 0 is a special value to indicate that the receiver shall use a special value for declaring leftr defect . The minimum valid threshold to declare leftr is ETR/2. The receiver shall ignore threshold values that are less than the minimum and shall use ETR/2 for declaring leftr defect instead (see clause 11.3.3). The valid values are all multiples of 0.01 from 0 to 0.99.