All MIBs › DOCS-IF31-MIB › docsIf31CmtsDsOfdmChanCyclicPrefix
docsIf31CmtsDsOfdmChanCyclicPrefix
Module: DOCS-IF31-MIB
OID (symbolic): DOCS-IF31-MIB::docsIf31CmtsDsOfdmChanCyclicPrefix
OID (numeric): 1.3.6.1.4.1.4491.2.1.28.1.19.1.14
Node type: OBJECT-TYPE
Type: DsOfdmCyclicPrefix
Access: read-only
Description: Cyclic prefix enables the receiver to overcome the effects of inter-symbol-interference and intercarrier-interference caused by micro-reflections in the channel. There are five possible values for the length of the CP and the choice depends on the delay spread of the channel - a longer delay spread requires a longer cyclic prefix. The cyclic prefix (in usec) are converted into samples using the sample rate of 204.8 Msamples/s and is an integer multiple of: 1/64 * 20 us.
What is docsIf31CmtsDsOfdmChanCyclicPrefix?
Reports the cyclic prefix length, in number of samples (converted from microseconds at a 204.8 Msamples/s sample rate), configured on this OFDM downstream channel from the CMTS's perspective; the cyclic prefix protects against inter-symbol and inter-carrier interference from micro-reflections, with DOCSIS 3.1 defining five possible lengths chosen based on the channel's delay spread. This is the CMTS-side counterpart to docsIf31CmDsOfdmChanCyclicPrefix, which admins can use as an indirect indicator of how noisy the CMTS judged this segment of plant to be when it configured the channel.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.19.1.14 snmpwalk -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmtsDsOfdmChanCyclicPrefix
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.19.1.14.1 snmpget -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmtsDsOfdmChanCyclicPrefix.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 |
| 1.3.6.1.4.1.4491.2.1.28.1.19 | docsIf31CmtsDsOfdmChanTable | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1.19.1 | docsIf31CmtsDsOfdmChanEntry | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1.19.1.14 | docsIf31CmtsDsOfdmChanCyclicPrefix | DOCS-IF31-MIB |