All MIBs › DOCS-IF31-MIB › docsIf31CmDsOfdmChanNumActiveSubcarriers
docsIf31CmDsOfdmChanNumActiveSubcarriers
Module: DOCS-IF31-MIB
OID (symbolic): DOCS-IF31-MIB::docsIf31CmDsOfdmChanNumActiveSubcarriers
OID (numeric): 1.3.6.1.4.1.4491.2.1.28.1.9.1.6
Node type: OBJECT-TYPE
Type: Unsigned32
Access: read-only
Description: This attribute represents the number of active data subcarriers within the OFDM downstream channel (i.e. this exclude subcarriers for continuous pilots and the PLC). For 4K FFT mode, the maximum number of subcarriers including continuous pilots and the PLC cannot exceed 3800, and for 8K FFT mode, the maximum number of active subcarriers including continuous pilots and the PLC cannot be greater than 7600.
However, there are a minimum of 56 continuous pilots in a 192MHz channel that has no exclusions, and the size of the PLC is 8 subcarriers for 4K FFT mode and 16 subcarriers for 8K FFT mode. Therefore the maximum value of NumActiveSubcarriers is 3736 (or 3800 - 56 - 8) for 4K FFT mode and 7528 (or 7600 - 56 - 16) for 8K FFT mode.
What is docsIf31CmDsOfdmChanNumActiveSubcarriers?
The count of active data subcarriers in this OFDM downstream channel, excluding continuous pilots and the PLC (Physical Layer Link Channel); the maximum is 3736 for 4K FFT mode or 7528 for 8K FFT mode given DOCSIS's minimum pilot and PLC overhead in a full 192 MHz channel. Admins use this to sanity-check that a channel is actually using close to its expected spectrum capacity rather than having excessive exclusions configured.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.9.1.6 snmpwalk -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmDsOfdmChanNumActiveSubcarriers
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.9.1.6.1 snmpget -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmDsOfdmChanNumActiveSubcarriers.1
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OID Breakdown
Upper-level ancestors (9 from the standard OID tree / other modules)
| Numeric OID | Name | Module |
|---|---|---|
| 1 | iso | LANART-AGENT |
| 1.3 | org | AirPair-MIB |
| 1.3.6 | dod | AirPair-MIB |
| 1.3.6.1 | internet | AirPair-MIB |
| 1.3.6.1.4 | private | AirPair-MIB |
| 1.3.6.1.4.1 | enterprises | AirPair-MIB |
| 1.3.6.1.4.1.4491 | cableLabs | CLAB-DEF-MIB |
| 1.3.6.1.4.1.4491.2 | clabProject | CLAB-DEF-MIB |
| 1.3.6.1.4.1.4491.2.1 | clabProjDocsis | CLAB-DEF-MIB |
| Numeric OID | Name | Module |
|---|---|---|
| 1.3.6.1.4.1.4491.2.1.28 | docsIf31Mib | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1 | docsIf31MibObjects | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1.9 | docsIf31CmDsOfdmChanTable | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1.9.1 | docsIf31CmDsOfdmChanEntry | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1.9.1.6 | docsIf31CmDsOfdmChanNumActiveSubcarriers | DOCS-IF31-MIB |