# tt_noc_alive

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## Name

### Prometheus Metric Name

```
tt_noc_alive
```

### Metric Path (tt-telemetry)

Schema:

```
{hostname}/tray{tray}/chip{chip}/noc{noc}/tt_noc_alive
```

Example path:

```
bh-glx-c09u02/tray1/chip2/noc0/tt_noc_alive
```

## Description

Indicates whether a single NOC (Network-on-Chip) responds to a read issued from the host. Each
collection cycle the telemetry server asks UMD's hang detector to issue a NOC read of a node-ID
register that is guaranteed to never legitimately hold `0xFFFFFFFF`. If the read returns the
all-ones fault signature, that NOC is considered hung; reset usually requires a board power-cycle.

The metric is emitted once per NOC on every MMIO-capable chip that runs a Wormhole or Blackhole
architecture (those are the devices for which UMD provides a NOC hang detector). The `noc` path
segment and label identify which NOC the measurement came from (`0` for NOC0, `1` for NOC1).

## Values

**Type:** Boolean

**Units:** None

**Allowable values:**
- **True (1)**: The NOC read returned a sane value; the NOC is responsive.
- **False (0)**: The NOC read returned `0xFFFFFFFF`; the 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.|
|noc|The NOC identifier on the chip (`0` for NOC0, `1` for NOC1).|