The Signal to Noise (SNR) threshold. This object
is applicable for modulation profile 1.
When the CMTS detects that the SNR goes lower than
ccsUpSpecMgmtSnrThres1, it switches to profile 2.
Therefore, ccsUpSpecMgmtSnrThres1 should be larger than
ccsUpSpecMgmtSnrThres2.
A value 0 indicates to bypass the threshold check.