All MIBs › DOCS-IF31-MIB › docsIf31CmDsOfdmChanCyclicPrefix
docsIf31CmDsOfdmChanCyclicPrefix
Module: DOCS-IF31-MIB
OID (symbolic): DOCS-IF31-MIB::docsIf31CmDsOfdmChanCyclicPrefix
OID (numeric): 1.3.6.1.4.1.4491.2.1.28.1.9.1.8
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 docsIf31CmDsOfdmChanCyclicPrefix?
Reports the cyclic prefix length, in number of samples, configured for this OFDM downstream channel; the cyclic prefix lets the receiver tolerate inter-symbol and inter-carrier interference caused by micro-reflections in the cable plant, and DOCSIS 3.1 defines five possible lengths chosen based on plant conditions. A longer cyclic prefix generally indicates a noisier plant that needed more protection against echoes, so admins can use this value as an indirect signal of plant quality on that channel.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.9.1.8 snmpwalk -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmDsOfdmChanCyclicPrefix
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.9.1.8.1 snmpget -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmDsOfdmChanCyclicPrefix.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 |
| 1.3.6.1.4.1.4491.2.1.28.1.9.1.8 | docsIf31CmDsOfdmChanCyclicPrefix | DOCS-IF31-MIB |