docsPnmCmtsUsOfdmaAQProbeTable
DOCS-PNM-MIB ·
.1.3.6.1.4.1.4491.2.1.27.1.3.3
Object
table
The purpose of upstream capture is to measure plant response and view
the underlying noise floor, by capturing at least one OFDMA symbol
during a scheduled active or quiet probe. An active probe provides the
partial functionality of a network analyzer, since the input is known
and the output is captured. This permits full characterization of the
linear and nonlinear response of the upstream cable plant. A quiet probe
provides an opportunity to view the underlying noise and ingress while
no traffic is being transmitted in the OFDMA band being measured.
The PNM server selects an active CM to analyze by specifying its MAC
address, or performs a quiet probe measurement. When enabled to perform
the capture, the CMTS selects a specified transmitting CM, or quiet
period when no CMs are transmitting, for the capture. The CMTS sets up
the capture as described in MULPIv3.1, selecting either an active SID
corresponding to the specified MAC address or the idle SID, and defining
an active or quiet probe. The active probe symbol for this capture
normally includes all non-excluded subcarriers across the upstream OFDMA
channel, with pre-equalization on or off as specified in the MIB. The quiet
probe symbol normally includes all subcarriers, that is, during the quiet
probe time there are no transmissions in the given upstream OFDMA channel.
For the quiet probe, the CMTS captures samples of at least one full OFDMA
symbol including the guard interval. The CMTS begins the capture with the
first symbol of the specified probe. The sample rate is the FFT sample rate
(102.4 Msps).
The CMTS reports the list of excluded subcarriers, the cyclic prefix length,
and the transmit window rolloff period in order to fully define the
transmitted waveform. The CMTS also reports the index of the starting sample
used by the receiver for its FFT. For possible comparison with other events,
the CMTS reports the timestamp corresponding to the beginning of the probe.
In the case where the P-MAPs for the OFDMA upstream being analyzed are being
sent in an OFDM downstream, the timestamp reported is the extended timestamp,
while in a case with OFDMA upstream channels but no OFDM downstream channels,
the reported timestamp is the D3.0 timestamp. For an active probe, the CMTS
reports the contents of the Probe Information Element (P-IE) message
describing that probe.
Context
- MIB
- DOCS-PNM-MIB
- OID
.1.3.6.1.4.1.4491.2.1.27.1.3.3- Type
- table
- Status
- current
- Parent
- docsPnmCmtsObjects
- Siblings
- 7
- Children
- 1
Syntax
No syntax metadata recorded.
Values & Constraints
No enumerated values or constraints recorded.
Related Objects
Sibling Objects
| Object | Type | Syntax | OID |
|---|---|---|---|
| docsPnmCmtsDsOfdmSymCapTable The purpose of downstream symbol capture is to provide partial
functionality of a network analyzer to analyze the response of the
cable plant.
At the CMTS, the transmit… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.3.1 |
| docsPnmCmtsDsOfdmNoisePwrRatioTable The purpose of downstream NPR measurement is to view the noise,
interference and intermodulation products underlying a portion of the
OFDM signal. As an out-of-service test, the C… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.3.2 |
| docsPnmCmtsUsImpNoiseTable This table provides statistics of burst/impulse noise occurring in a
selected narrow band. A bandpass filter is positioned in an unoccupied
upstream band. A threshold is set, ener… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.3.4 |
| docsPnmCmtsUsHistTable The purpose of the upstream histogram is to provide a measurement of
nonlinear effects in the channel such as amplifier compression and
laser clipping. For example, laser clipping… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.3.5 |
| docsPnmCmtsUsOfdmaRxPwrTable The purpose of the upstream channel power metric is to provide an
estimate of the total received power in a specified OFDMA channel at
the F connector input of the CMTS line card … | table | - | .1.3.6.1.4.1.4491.2.1.27.1.3.6 |
| docsPnmCmtsUsOfdmaRxMerTable This item provides measurements of the upstream receive modulation
error ratio (RxMER) for each subcarrier. The CMTS measures the RxMER
using an upstream probe, which is not subje… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.3.7 |
| docsPnmCmtsUsSpecAnTable The upstream triggered spectrum analysis measurement provides a
wideband spectrum analyzer function in the CMTS which can be triggered
to examine desired upstream transmissions as… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.3.8 |
Child Objects
| Object | Type | Syntax | OID |
|---|---|---|---|
| docsPnmCmtsUsOfdmaAQProbeEntry The conceptual row of the 'docsPnmCmtsUsOfdmaAQProbeTable'. An
instance is dynamically created and exists for an associated ifIndex
of the physical upstream channel upon which the… | row | - | .1.3.6.1.4.1.4491.2.1.27.1.3.3.1 |