# tt_cable_present

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## Name

### Prometheus Metric Name

```
tt_cable_present
```

### Metric Path (tt-telemetry)

Schema:

```
{hostname}/tray{tray}/qsfp/port{N}/tt_cable_present
```

Example path:

```
bh-glx-c09u02/tray1/qsfp/port1/tt_cable_present
```

`{N}` is the tray-scoped QSFP port number, 1 through 14. The mapping to the
physical J-designator is:

| N | Designator | | N | Designator |
|---|---|---|---|---|
| 1 | J101 | | 8  | J302 |
| 2 | J102 | | 9  | J303 |
| 3 | J201 | | 10 | J304 |
| 4 | J202 | | 11 | J401 |
| 5 | J203 | | 12 | J402 |
| 6 | J204 | | 13 | J403 |
| 7 | J301 | | 14 | J404 |

The exact designator is also emitted as the `qsfp_designator` label on every
sample.

## Description

Whether a QSFP-DD cable is physically connected at a specific tray-level port.
This metric is a tray-scoped reorganization of the same IPMI-sourced data used
by `tt_ethernet_cable_present`: one instance exists per unique physical QSFP-DD
connector on each tray, independent of how many Ethernet channels map to that
connector. Consumers who want to reason about "is this cable plugged in?" at
the hardware level (rather than per-channel) should query this metric.

Values are read from the same background-refreshed IPMI I2C cache as the
per-channel metric. The poller runs approximately every 60 seconds; a per-port
read failure leaves the previous cached value in place. See
`tt_ethernet_cable_present` for details of the polling mechanism.

### Initial / pre-scan value

Like `tt_ethernet_cable_present`, this metric defaults to `true` (connected)
until the first scan result for its `(tray, port_id)` entry lands in the
cache, avoiding spurious "cable missing" alarms during startup. Consult
`tt_ipmi_service_healthy` for overall IPMI service health.

### When the metric is created

- IPMI must be enabled (see `--enable_ipmi`).
- An FSD must be provided at startup; without port-type information we cannot
  identify which channels correspond to QSFP-DD ports.
- At least one Ethernet endpoint on the host must have a physical link of type
  `QSFP_DD` for the `(tray, port_id)` in question.

## Values

**Type:** Boolean

**Units:** None

**Allowable values:**
- **True (1)**: A QSFP-DD cable is physically inserted at this port, *or* the
  first scan has not yet populated this port's cache entry (startup default).
- **False (0)**: The most recent successful scan confirmed the port is empty.

## Prometheus Labels

|Label Name|Value|
|---|---|
|hostname|The host from which the metric was collected.|
|tray|The tray (UBB) that the port is on.|
|port_id|The tray-scoped port identifier (1–14) from the FSD. Useful for joining against `tt_ethernet_cable_present`, which carries the same label.|
|qsfp_designator|The QSFP reference designator (e.g., `j101`–`j404`). Unique within a tray.|