All MIBs › DOCS-IF31-MIB › docsIf31CmUsOfdmaChanCyclicPrefix
docsIf31CmUsOfdmaChanCyclicPrefix
Module: DOCS-IF31-MIB
OID (symbolic): DOCS-IF31-MIB::docsIf31CmUsOfdmaChanCyclicPrefix
OID (numeric): 1.3.6.1.4.1.4491.2.1.28.1.13.1.7
Node type: OBJECT-TYPE
Type: UsOfdmaCyclicPrefix
Access: read-only
Description: Cyclic prefix is added in order to enable the receiver to overcome the effects of inter-symbol interference (ISI) and inter-carrier interference caused by microreflections in the channel. The cyclic prefix (in usec) is converted into samples using the sample rate of 102.4 Msamples/s. There are eleven 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.
What is docsIf31CmUsOfdmaChanCyclicPrefix?
Reports the cyclic prefix length, in number of samples (converted from microseconds at a 102.4 Msamples/s sample rate), configured for this OFDMA upstream channel; the cyclic prefix protects against inter-symbol and inter-carrier interference from micro-reflections in the plant, with DOCSIS 3.1 defining eleven possible lengths chosen based on the channel's delay spread. A longer configured cyclic prefix generally indicates the CMTS compensated for a plant segment with more signal reflections, so admins can use this as an indirect signal-quality indicator for that upstream channel.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.13.1.7 snmpwalk -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmUsOfdmaChanCyclicPrefix
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.4.1.4491.2.1.28.1.13.1.7.1 snmpget -v2c -c public <target> DOCS-IF31-MIB::docsIf31CmUsOfdmaChanCyclicPrefix.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 |
| 1.3.6.1.4.1.4491.2.1.28.1.13 | docsIf31CmUsOfdmaChanTable | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1.13.1 | docsIf31CmUsOfdmaChanEntry | DOCS-IF31-MIB |
| 1.3.6.1.4.1.4491.2.1.28.1.13.1.7 | docsIf31CmUsOfdmaChanCyclicPrefix | DOCS-IF31-MIB |