PNM Operations - Downstream OFDM FEC Summary¶

Forward Error Correction Trends For Proactive Monitoring Of OFDM Downstream Health.

Overview¶

Retrieves DOCSIS 3.1 OFDM Forward Error Correction (FEC) summary statistics per modulation profile, suitable for dashboards and automation. Each profile contains a time‑series of codeword counters: total, corrected, and uncorrectable. Use this to separate transient bursts from persistent issues and to validate error‑protection efficacy.

Endpoint¶

POST /docs/pnm/ds/ofdm/fecSummary/getCapture

Request¶

Refer to Common → Request.
Deltas (Analysis‑Only Additions): optional analysis, analysis.output, and analysis.plot.ui controls (same pattern as RxMER).

Delta Table¶

JSON path	Type	Allowed values / format	Default	Description
`analysis.type`	string	"basic"	"basic"	Selects the analysis mode used during capture processing.
`analysis.output.type`	string	"json", "archive"	"json"	Output format: `json` returns inline `data`; `archive` returns a ZIP (CSV exports and PNG plots).
`analysis.plot.ui.theme`	string	"light", "dark"	"dark"	Theme hint for plot generation (colors, grid, ticks). Does not affect raw metrics/CSV.

Capture Settings¶

JSON path	Type	Example	Description
`capture_settings.fec_summary_type`	int	2	Summary type per SNMP `docsPnmCmDsOfdmFecSumType`. 2 = 24‑hour, 3 = 10‑minute.

Notes¶

Your project setting: Type 2 corresponds to a 24‑hour interval; Type 3 corresponds to a 10‑minute interval.
The time‑series set count depends on the type (see Return Structure → number_of_sets).
Profile 255 commonly refers to NCP (Next Codeword Pointer).
To capture specific channels, set cable_modem.pnm_parameters.capture.channel_ids. Empty or missing means all channels.

Example Request¶

{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.10",
        "ipv6": "2001:db8::10"
      },
      "capture": {
        "channel_ids": []
      }
    },
    "snmp": { "snmpV2C": { "community": "private" } }
  },
  "analysis": {
    "type": "basic",
    "output": { "type": "json" },
    "plot": { "ui": { "theme": "dark" } }
  },
  "capture_settings": {
    "fec_summary_type": 2
  }
}

Response¶

Standard envelope with payload under data.

Abbreviated Example¶

{
  "mac_address": "aa:bb:cc:dd:ee:ff",
  "status": 0,
  "message": null,
  "data": {
    "analysis": [
      {
        "device_details": {
          "system_description": {
            "HW_REV": "1.0",
            "VENDOR": "LANCity",
            "BOOTR": "NONE",
            "SW_REV": "1.0.0",
            "MODEL": "LCPET-3"
          }
        },
        "channel_id": 159,
        "profiles": [
          {
            "profile": 255,
            "number_of_sets": 600,
            "codewords": {
              "timestamps": [],
              "total_codewords": [],
              "corrected": [],
              "uncorrectable": []
            }
          }
        ]
      }
    ],
    "primative": [
      {
        "status": "SUCCESS",
        "pnm_header": {
          "file_type": "PNN",
          "file_type_version": 8,
          "major_version": 1,
          "minor_version": 0,
          "capture_time": 1762466502
        },
        "channel_id": 159,
        "mac_address": "aa:bb:cc:dd:ee:ff",
        "summary_type": 2,
        "num_profiles": 5,
        "fec_summary_data": [
          {
            "profile_id": 255,
            "number_of_sets": 600,
            "codeword_entries": {
              "timestamp": [],
              "total_codewords": [],
              "corrected": [],
              "uncorrectable": []
            }
          }
        ],
        "summary_type_label": "24-hour interval"
      }
    ],
    "measurement_stats": [
      {
        "index": 3,
        "entry": {
          "docsPnmCmDsOfdmFecSumType": "24-hour",
          "docsPnmCmDsOfdmFecFileEnable": true,
          "docsPnmCmDsOfdmFecMeasStatus": "sample_ready",
          "docsPnmCmDsOfdmFecFileName": "ds_ofdm_codeword_error_rate_aabbccddeeff_159_1762468766.bin"
        }
      },
      {
        "index": 48,
        "entry": {
          "docsPnmCmDsOfdmFecSumType": "10-minute",
          "docsPnmCmDsOfdmFecFileEnable": true,
          "docsPnmCmDsOfdmFecMeasStatus": "sample_ready",
          "docsPnmCmDsOfdmFecFileName": "ds_ofdm_codeword_error_rate_aabbccddeeff_160_1762468768.bin"
        }
      }
    ]
  }
}

Return Structure¶

Top‑Level Envelope¶

Field	Type	Description
`mac_address`	string	Request echo of the modem MAC.
`status`	int	0 on success, non‑zero on error.
`message`	string\|null	Optional message describing status.
`data`	object	Container for results (`analysis`, `primative`, `measurement_stats`).

`data.analysis[]`¶

Analysis view per channel, grouped by profile.

Field	Type	Description
device_details.*	object	System descriptor at analysis time.
channel_id	int	OFDM downstream channel ID.
profiles[].profile	int	Modulation profile identifier (`0..N`, `255` for NCP in many deployments).
profiles[].number_of_sets	int	Number of time samples in this capture (depends on summary type).
profiles[].codewords.*	arrays	Parallel arrays: `timestamps`, `total_codewords`, `corrected`, `uncorrectable`.

`data.primative[]`¶

Normalized raw capture for export/plotting.

Field	Type	Description
status	string	Result for this capture (e.g., `SUCCESS`).
pnm_header.*	object	PNM header (type, version, capture time).
channel_id	int	Channel ID.
mac_address	string	MAC address.
summary_type	int	SNMP value (2 or 3).
num_profiles	int	Number of profiles present in the payload.
fec_summary_data[]	array	Raw profile entries as captured.
fec_summary_data[].profile_id	int	Profile ID (e.g., `0..N`, `255`).
fec_summary_data[].number_of_sets	int	Number of time samples in the series.
fec_summary_data[].codeword_entries.*	arrays	`timestamp`, `total_codewords`, `corrected`, `uncorrectable`.
summary_type_label	string	Human‑readable label (e.g., `24-hour interval`).

`data.measurement_stats[]`¶

Snapshot of CM FEC‑summary configuration and state via SNMP at capture time.

Field	Type	Description
index	int	SNMP table row index.
entry.docsPnmCmDsOfdmFecSumType	string	Selected summary type (`24-hour`, `10-minute`).
entry.docsPnmCmDsOfdmFecFileEnable	boolean	Whether CM capture‑to‑file was enabled.
entry.docsPnmCmDsOfdmFecMeasStatus	string	Measurement status (e.g., `sample_ready`).
entry.docsPnmCmDsOfdmFecFileName	string	Device‑side filename of the summary payload.

Matplot Plotting¶

Plot	Description
Uncorrectable Rate vs Time	Line or area plot of uncorrectable codewords to visualize bursts and persistent tails.
Corrected vs Uncorrectable (Stacked)	Stacked area of corrected/uncorrectable counts to show protection effectiveness over time.
Profile Comparison	Multiple lines by profile to identify outliers (e.g., NCP vs data profiles).

Notes¶

Summary Type Mapping (Project Standard): 2 → 24‑hour (1 record/min, up to 1440), 3 → 10‑minute (1 record/sec, up to 600).
Use per‑profile trends to identify when and where errors occur (e.g., profile‑specific ingress or plant issues).
For NCP display questions, align with current ECN/SPEC guidance when interpreting corrected counters.

PNM Operations - Downstream OFDM FEC Summary¶

Overview¶

Endpoint¶

Request¶

Delta Table¶

Capture Settings¶

Notes¶

Example Request¶

Response¶

Abbreviated Example¶

Return Structure¶

Top‑Level Envelope¶

data.analysis[]¶

data.primative[]¶

data.measurement_stats[]¶

Matplot Plotting¶

Notes¶

`data.analysis[]`¶

`data.primative[]`¶

`data.measurement_stats[]`¶