# tt_device_accessible

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## Name

### Prometheus Metric Name

```
tt_device_accessible
```

### Metric Path (tt-telemetry)

Schema:

```
{hostname}/tray{tray}/chip{chip}/tt_device_accessible
```

Example path:

```
bh-glx-c09u02/tray1/chip2/tt_device_accessible
```

## Description

Whether a specific device is accessible and fully responsive. This provides a per-device accessibility indicator.

A device is considered accessible only when *all* of the following hold during the collection cycle:

- **All of its metrics were readable** (`tt_device_metrics_readable_percent` is 100%).
- **Its PCIe link is alive** (`tt_pcie_link_alive` is true — the chip responds to a PCIe BAR read).
- **All of its NOCs are alive** (`tt_noc_alive` is true for every NOC — the chip responds to NOC reads).

If any of these checks fails, the device is reported inaccessible.

## Values

**Type:** Boolean

**Units:** None

**Allowable values:**
- **True (1)**: The device is accessible: all metrics were readable and its PCIe link and NOCs are alive.
- **False (0)**: The device is not accessible: one or more metrics could not be read, or the PCIe link or a NOC appears hung.

## Prometheus Labels

|Label Name|Value|
|---|---|
|hostname|The host from which the metric was collected.|
|hall|The datacenter hall where the host is located. Sourced from the Factory System Descriptor (FSD).|
|aisle|The datacenter aisle where the host is located. Sourced from the Factory System Descriptor (FSD).|
|rack|The rack number where the host is located. Sourced from the Factory System Descriptor (FSD).|
|shelf_u|The shelf U position in the rack where the host is located. Sourced from the Factory System Descriptor (FSD).|
|tray|The tray (UBB) that the device is located on.|
|chip|The ASIC location within the tray.|