The two-run method
Almost every packet loss question at home comes down to one fork: is the loss in your own network, or beyond it? You can settle that with two runs of the packet loss test. The trick is to change only one thing between them.
- Run 1, wifi. On the device with the problem, in the place where it happens, 30 seconds. Note the loss, jitter and whether the red marks cluster.
- Run 2, cable. Plug the same device into the router with an Ethernet cable. Stop other devices from downloading or streaming. Run again, same length.
Reading the two results
If you cannot get a cable to the device, carry a laptop to the router instead and compare wifi and cable there. It is the same comparison, just in a different room.
| Wifi run | Cable run | What it means |
|---|---|---|
| Loss or high jitter | Clean | The wifi is the whole problem. |
| Loss | Same loss | The problem is the router, modem, line or provider. |
| Clean | Clean | Your connection is fine; look at the game or service, or test at a different time. |
| Loss | Less loss, not zero | Two problems: the wifi, plus something on the line. |
Why wifi drops packets
Wifi is a radio link shared by every device on your network and, on the same channel, by every nearby network too. Only one transmitter can use a channel at a time, so devices take turns, and when two talk at once both frames are corrupted. A weak signal makes frames more likely to arrive damaged. Wifi retries a damaged frame several times; each retry adds delay, which is why wifi jitter is high, and if all retries fail the packet is dropped.
Walls, floors and furniture weaken the signal, water and metal most of all. The 2.4 GHz band passes through walls better but is crowded and slower; the 5 GHz band is faster and less crowded but fades faster with distance. Microwave ovens, cordless phones and some baby monitors interfere with 2.4 GHz directly.
Fixing wifi packet loss
- Put the router high, central and in the open, not in a cupboard or behind a TV.
- Use 5 GHz for devices in the same or the next room, and 2.4 GHz only for distant ones.
- Set a fixed channel instead of automatic if you live near many other networks: 1, 6 or 11 on 2.4 GHz.
- Add a mesh node or access point connected by cable for rooms the router cannot reach well. Wireless repeaters halve their own speed and add jitter.
- Update the wifi driver on laptops and the firmware on the router.
- For a console or gaming PC, run a cable or use a powerline adapter. It is the only fix that removes wifi loss completely.
When the cable run still shows loss
Then the wifi is not the cause. Restart the modem and router, try a different cable and port, and if possible plug directly into the modem to take the router out of the chain. If loss persists on a direct cable with nothing else running, the problem is the line or the provider. How to fix packet loss covers what to check and what to say when you report it.