With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
adsl2LConfProfRaDsNrmsDs
ADSL2 L Configuration Profile Ra Downstream Nrms Downstream
1.3.6.1.2.1.10.238.1.5.1.2.1.11
The Downstream Down-Shift Noise Margin value, to be used when adsl2LConfProfRaModeDs 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 adsl2LConfProfRaDsTimeDs, the ATU-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).
Back to ADSL2-LINE-MIB MIB page.
IPHost Network monitor allows you to monitor adsl2LConfProfRaDsNrmsDs on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.