The Carrier to Noise (CNR) threshold. This
object is applicable for modulation profile 1.
When the CMTS detects that the CNR goes lower than
ccsUpSpecMgmtCnrThres1, it switches to profile 2.
Therefore, ccsUpSpecMgmtCnrThres1 should be larger
than ccsUpSpecMgmtCnrThres2.
A value 0 indicates to bypass the threshold check.