# Architecture

> How video, detections and control move through the X-Edge Vision appliance.

The appliance keeps video and detection data on **separate paths**. Video is
never decoded or re-encoded on its way to your browser, and the backend never
touches a video frame. Detections travel as small messages and are drawn over
the frame they were computed on.

```mermaid
flowchart LR
  cam[IP cameras<br/>RTSP] --> relay[Video relay<br/>MediaMTX]
  cam --> pipe[Detection pipeline<br/>DeepStream]
  relay -- "WebRTC video" --> browser[Operator console<br/>in your browser]
  pipe -- "detections" --> api[EdgeVision API]
  api -- "WebSocket + REST" --> browser
  api --- db[(SQLite)]
  api --- models[(Model store)]
  api -. "supervises" .-> pipe
  api -. "keeps camera paths" .-> relay
```

## The three planes

- **Video plane.** Camera, then relay, then browser over WebRTC. The relay
  passes the video through without decoding it.
- **Metadata plane.** The detection pipeline publishes one detection message per
  frame. The API forwards it over a WebSocket, and the browser draws it over the
  frame it belongs to.
- **Control and state.** The API starts and stops the detection pipeline, keeps
  the relay's camera paths in place, builds TensorRT engines, handles
  authentication, and stores all state in a local SQLite database.

## Network ports

The device listens on these ports. Allow them on your site network.

| Port | Used for |
|---|---|
| `5080/tcp` | Operator console and API |
| `8554/tcp` | RTSP, served by the relay |
| `8889/tcp` | WebRTC signalling (WHEP) |
| `8189/udp` | WebRTC media (ICE) |

If `8189/udp` is blocked, the console connects but no video arrives.

## Failure behaviour

- The API can run without video. If the relay stops, camera tiles show no
  picture but the console keeps working. When the relay comes back, the API
  restores its camera paths within about 30 seconds, without a restart.
- A release that fails to start is rolled back by the installer, along with the
  database snapshot taken before it. See [Updating a device](/operate/updating-a-device/).

  - [Running and status](/operate/running-and-status/) — Check what is running and where its logs are.
  - [API overview](/api-reference/overview/) — The public interfaces and how they are versioned.