I want to know what MIB variables of DOCS-IF-MIB are returned by modems that are linked up with DCSIS 3.1 OFDM channels.
I want to know especially "docsIfDownChannelWidth" and "docsIfSigQSignalNoise".
However I have only DOCSIS 3.0 CMTS, so I can't test it by myself.
Can anybody teach me?
On the CM docsIfDownChannelWidth will return 0 and docsIfSigQSignalNoise will not have an entry
Index 79 is the OFDM channel
snmpbulkwalk -v2c -c private 10.1.217.18 DOCS-IF-MIB::docsIfDownChannelWidth
DOCS-IF-MIB::docsIfDownChannelWidth.3 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.48 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.49 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.50 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.51 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.52 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.53 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.54 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.55 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.56 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.57 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.58 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.59 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.60 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.61 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.62 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.63 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.64 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.65 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.66 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.67 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.68 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.69 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.70 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.71 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.72 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.73 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.74 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.75 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.76 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.77 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.78 = INTEGER: 6000000 hertz
DOCS-IF-MIB::docsIfDownChannelWidth.79 = INTEGER: 0 hertz
There is no entry for docsIfSigQSignalNoise on OFDM channels... you have to use the RxMER values....
snmpbulkwalk -v2c -c private 10.1.217.18 DOCS-IF-MIB::docsIfSigQSignalNoise
DOCS-IF-MIB::docsIfSigQSignalNoise.3 = INTEGER: 41.4 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.48 = INTEGER: 41.4 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.49 = INTEGER: 41.3 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.50 = INTEGER: 41.2 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.51 = INTEGER: 41.4 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.52 = INTEGER: 41.4 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.53 = INTEGER: 41.5 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.54 = INTEGER: 41.7 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.55 = INTEGER: 41.6 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.56 = INTEGER: 41.5 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.57 = INTEGER: 41.5 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.58 = INTEGER: 41.4 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.59 = INTEGER: 41.2 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.60 = INTEGER: 41.0 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.61 = INTEGER: 41.1 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.62 = INTEGER: 41.1 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.63 = INTEGER: 41.2 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.64 = INTEGER: 41.3 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.65 = INTEGER: 41.1 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.66 = INTEGER: 41.1 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.67 = INTEGER: 41.1 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.68 = INTEGER: 41.2 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.69 = INTEGER: 40.9 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.70 = INTEGER: 40.8 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.71 = INTEGER: 40.6 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.72 = INTEGER: 40.7 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.73 = INTEGER: 40.6 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.74 = INTEGER: 40.5 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.75 = INTEGER: 40.3 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.76 = INTEGER: 40.2 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.77 = INTEGER: 40.1 TenthdB
DOCS-IF-MIB::docsIfSigQSignalNoise.78 = INTEGER: 38.5 TenthdB
To actually get the channel width of an OFDM channel you need to either do some detailed calculations to get it down to the subcarrier and exclude any exclusion bands or you can get a rough size by grabbing these Oids from the CM:
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency
the tricky part is that index 0 (655 MHz in this case) is the PLC channel so we want to ignore it. and the calculation is
(741 - 651) + 6 = 96
you add 6 since these are center frequencies
snmpbulkwalk -v2c -c private 10.1.217.18 DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.0 = Gauge32: 655000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.1 = Gauge32: 651000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.2 = Gauge32: 657000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.3 = Gauge32: 663000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.4 = Gauge32: 669000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.5 = Gauge32: 675000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.6 = Gauge32: 681000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.7 = Gauge32: 687000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.8 = Gauge32: 693000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.9 = Gauge32: 699000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.10 = Gauge32: 705000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.11 = Gauge32: 711000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.12 = Gauge32: 717000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.13 = Gauge32: 723000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.14 = Gauge32: 729000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.15 = Gauge32: 735000000 Hz
DOCS-IF31-MIB::docsIf31CmDsOfdmChannelPowerCenterFrequency.79.16 = Gauge32: 741000000 Hz
to get a signalQuality single value for a OFDM channel use this oid
DOCS-PNM-MIB::docsPnmCmDsOfdmRxMerMean
snmpbulkwalk -v2c -c private 10.1.217.18 DOCS-PNM-MIB::docsPnmCmDsOfdmRxMerMean
DOCS-PNM-MIB::docsPnmCmDsOfdmRxMerMean.79 = Gauge32: 3865 hundredthDb
so in this case the value is 38.65 dB
you can also get the stdDev for the value with this oid
snmpbulkwalk -v2c -c private 10.1.217.18 DOCS-PNM-MIB::docsPnmCmDsOfdmRxMerStdDev
DOCS-PNM-MIB::docsPnmCmDsOfdmRxMerStdDev.79 = Gauge32: 66 hundredthDb
so value would be 38.65 dB +/- 0.66 dB
Hello kwesibrunee.
I appreciate for your kindly explanation.
I have gotten necessary information from your post.
Thank you again for your help.