(RA-DSNRMds).
The Downstream Down-Shift Noise Margin value, to be used when
xdsl2LConfProfRaModeDs is set to dynamicRa. If the downstream
noise margin is below this value and stays below that for more
than the time specified by the xdsl2LConfProfRaDsTimeDs, the
xTU-R shall attempt to decrease the downstream net data rate.
The Downstream Down-shift Noise Margin ranges from 0 to 310
units of 0.1 dB (Physical values are 0 to 31 dB).