> For the complete documentation index, see [llms.txt](https://docs.vex-nx.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vex-nx.com/labs/link-inspector-and-impairment.md).

# Link inspector and impairment

![Link impairment controls](https://1807546539-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhgHCHWL3861o2DBW53aA%2Fuploads%2FaPC9utBChuhTxGyUlfLZ%2Fve20261112v5-tutorial-link-impairment.png?alt=media)

GUI walkthrough for the link dock: Properties, Traffic, Capture, and Impairment (delay / jitter / loss).

## Goal

Inspect a link and apply (then clear) quality impairments for demos and failure drills.

## Why Link Engineering exists

Nodes can be "up" while the path is bad. Impairment lets you inject delay, jitter, or loss on a fabric link without rebuilding the topology.

## GUI tutorial

### Step 1 - Select a link

1. Open the lab (Design or Operate)
2. Click a **link** between two nodes on the canvas
3. The right / bottom **Link** dock opens

![Link Properties](https://1807546539-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhgHCHWL3861o2DBW53aA%2Fuploads%2Fgydhe4mI1cj21SoHM55b%2Fve20261112v5-tutorial-link-properties.png?alt=media)

|                  |                                            |
| ---------------- | ------------------------------------------ |
| **What you see** | Link Properties (endpoints, ifaces, style) |
| **Expected**     | Selection highlights the edge              |

### Step 2 - Properties tab

1. Confirm source / target node and interface names
2. Adjust label / path style if offered (Design)
3. Use this tab to verify you clicked the intended edge

### Step 3 - Traffic tab

1. Open **Traffic** on the link dock
2. Compare with canvas paint in [Traffic Lens](/labs/traffic-lens.md)

|                  |                                                  |
| ---------------- | ------------------------------------------------ |
| **What you see** | Per-link traffic / rates when available          |
| **Expected**     | Numbers update when nodes run and traffic exists |

### Step 4 - Capture tab

1. Open **Capture**
2. Start / Stop / Download for this link
3. Full studio: [Packet capture](/labs/packet-capture.md)

### Step 5 - Impairment tab

![Impairment controls](https://1807546539-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhgHCHWL3861o2DBW53aA%2Fuploads%2FaPC9utBChuhTxGyUlfLZ%2Fve20261112v5-tutorial-link-impairment.png?alt=media)

1. Open **Impairment** (sometimes labeled Link quality)
2. Choose a preset **or** set Delay (ms), Jitter, Loss (%)
3. Click **Apply** / **Save**

|                  |                                           |
| ---------------- | ----------------------------------------- |
| **What you see** | Impairment controls for the selected link |
| **Expected**     | Apply succeeds; toast or badge confirms   |

### Step 6 - See the effect

![Impaired link](https://1807546539-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhgHCHWL3861o2DBW53aA%2Fuploads%2F5KZ48juLCgXSEgGXwYFI%2Fve20261112v5-tutorial-link-impaired.png?alt=media)

1. Keep nodes running
2. Ping across the link from consoles - RTT/loss should reflect the settings when the backend enforces impairment
3. Canvas may show a quality badge depending on build

|                  |                                                                          |
| ---------------- | ------------------------------------------------------------------------ |
| **What you see** | Link still selected; impairment active                                   |
| **Expected**     | Measurable degrade on the path, or clear UI state that impairment is set |

### Step 7 - Clear impairment

1. Impairment tab -> reset / clear / set delay and loss to 0
2. Apply again
3. Confirm pings return to normal

## Expected result

* One click on a link opens Properties / Traffic / Capture / Impairment
* Impairment applies without deleting the link
* Capture tab shares the same job model as the Captures dock

## If it fails

* No dock on click -> zoom in; click the edge path (not only the label)
* Impairment controls missing -> edition / feature gate; see [Features](/getting-started/features.md)
* Apply does nothing measurable -> confirm nodes are **running**; wait a few seconds; re-ping
* During Traffic Lens, classic inspector may sit behind Traffic chrome -> exit Traffic or use the Traffic dock first

## Related

* [Packet capture](/labs/packet-capture.md)
* [Traffic Lens](/labs/traffic-lens.md)
* [Design mode](/labs/design-mode.md)
* [Operate and consoles](/labs/operate-and-consoles.md)


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