# Physical appliance modes and switching between them

## **Available Appliance Modes**

Vectra physical appliances operate in one of three modes:

<table><thead><tr><th width="100" align="center"></th><th></th></tr></thead><tbody><tr><td align="center"><strong>Mode</strong></td><td><strong>Description</strong></td></tr><tr><td align="center">Sensor</td><td><ul><li>Captures / deduplicates raw network traffic.</li><li>Houses rolling capture buffer to enable PCAP retrieval when requested from the Brain.</li><li>Forwards metadata to the Brain.</li><li>Must be paired to a Brain.</li></ul></td></tr><tr><td align="center">Brain</td><td><ul><li>Pairs with Sensors (network data sources) and processes / deduplicates forwarded metadata.</li><li>Optionally forwards the metadata received from Sensors when licensed for Stream (RUX and QUX) or Recall (QUX only).</li><li>Communicates with the Vectra Cloud in RUX deployments.</li><li>Communicates with local integration points.</li><li>Serves the UI in QUX deployments.</li></ul></td></tr><tr><td align="center">Mixed</td><td><ul><li>Performs both Brain and Sensor functions.</li></ul></td></tr></tbody></table>

* [B-Series appliances](/deployment/ndr-physical-appliances/b-series.md) can only be deployed in Brain mode.
* [S-Series appliances](/deployment/ndr-physical-appliances/s-series.md) can only be deployed in Sensor mode.
* [X-Series appliances](/deployment/ndr-physical-appliances/x-series.md) can be deployed in Brain, Sensor, or Mixed modes.
* All [NDR virtual / cloud appliances](/deployment/ndr-virtual-cloud-appliances.md) support only Brain or Sensor mode.
  * Virtual appliances do NOT support Mixed mode.

## **Determining the Current Mode**

To display the current mode of a Vectra appliance:

* Login on the appliance cli as the user `vectra` .
  * See [SSH login process for CLI](/deployment/appliance-operations/ssh-login-process-for-cli.md) for more details.
* Run the command `show mode` .

Example Below:

```ckeditor_codeblock
vscli > show mode
Mode: mixed
```

## **Switching Between Modes**

The method for converting a Vectra appliance from one mode to another depends on the appliance's present mode. The following table summarizes the supported mode conversion:

<table><thead><tr><th width="139.83984375" align="center">Current Mode</th><th width="137.2109375" align="center">Desired Mode</th><th>Applicability and Guidance</th></tr></thead><tbody><tr><td align="center">Brain</td><td align="center">Sensor</td><td><p>Contact Vectra Support</p><ul><li>Brain data will be lost during conversion.</li><li>Appliance will reboot and come up in Sensor mode.</li></ul></td></tr><tr><td align="center">Brain</td><td align="center">Mixed</td><td><p>Perform <code>set mode mixed</code> at the CLI of your Brain.</p><ul><li>There will be no data loss.</li></ul></td></tr><tr><td align="center">Sensor</td><td align="center">Brain</td><td>Not supported</td></tr><tr><td align="center">Sensor</td><td align="center">Mixed</td><td>Not supported</td></tr><tr><td align="center">Mixed</td><td align="center">Brain</td><td><p>Perform <code>set mode brain</code> at the CLI of your Brain.</p><ul><li>There will be no data loss.</li><li>Match must be disabled on the Mixed mode appliance before attempting conversion.  See <strong>Please Note:</strong> box below for more details.</li></ul></td></tr><tr><td align="center">Mixed</td><td align="center">Sensor</td><td><p>Contact Vectra Support</p><ul><li>Brain data will be lost during conversion</li><li>Appliance will reboot and come up in Sensor mode</li></ul></td></tr></tbody></table>

**As you can see from the above table:**

* It is straightforward to toggle an appliance between Mixed-mode and Brain mode.
  * The provided commands should be entered at the CLI while logged in as the `vectra` user.
* Vectra Support will need to be engaged to convert a Brain or Mixed-mode appliance to Sensor mode.

{% hint style="warning" %}
**Please Note:**

* Conversion to Sensor mode is a one way process.
* Once an appliance has been converted to Sensor mode, it cannot later be reverted or converted back to Brain or Mixed mode.
* Conversion from Mixed to Brain mode is NOT supported when Match is enabled on the Mixed mode appliance.
  * Please disable Match on the Mixed mode appliance before attempting conversion.
  * Vectra plans to add a warning about this to the CLI command in v9.12 and above and disallow conversion attempts with Match enabled.
    {% endhint %}


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