How to Reduce Wi-Fi Speed ​​on an ADSL Router: A Complete Guide with Settings

Have you noticed that your Wi-Fi is slowing down, not because of overload, but because someone at home is actively downloading torrents, playing online games, or watching 4K videos? Or perhaps you need to limit the speed for the guest network to keep the main traffic stable? In this case, ADSL routers (even with outdated models based on Annex A/B) this is quite possible - and does not always require the purchase of new equipment.

In this article we will look at 5 working methods Reduce Wi-Fi speed: from basic settings QoS to manual MAC address restrictions. We will pay special attention TP-Link TD-W8960N routers, D-Link DSL-2640U And Asus DSL-N12U — the most common in homes that still use ADSL. We'll also find out why the speed sometimes "cuts" on its own (spoiler: it's the culprit DSLAM on the provider's side), and how to check it.

A word of warning: if your router is older than 2015, some features may be missing. But even in this case, there is a workaround—for example, through alternative firmware or configuring client devices. Let's start with the simplest.

1. Checking the current speed: where does the problem come from?

Before limiting anything, make sure the problem is with your network and not your provider. ADSL connections (unlike fiber optics) are extremely sensitive to:

• 📶 Length and quality of the telephone line — the further from the ATS, the lower the speed.
• 🌧️ Weather conditions - Rain or humidity degrades the signal on copper wires.
• 🔌 Electromagnetic interference from other devices (microwaves, cordless telephones).

To check real speed without restrictions:

1. Connect your computer to the router via cable (not via Wi-Fi!).
2. Run the test on Speedtest.net or Yandex.Internetometer.
3. Compare the result with your provider's plan. If the speed is 30% or more lower, the problem is with the line, not the router settings.

If the test showed that the channel 100% loaded If it's due to a single device (for example, a smartphone using a torrent), consider limiting it. If the speed is already low, first call your provider and ask them to check the line. SHDSL-interference.

2. Speed ​​limiting via QoS (Quality of Service)

QoS (or Quality of service) is a built-in router feature that allows for prioritized traffic distribution. In the context of ADSL routers, it operates more simply than in modern gigabit models, but it is sufficient for basic tasks.

How to configure QoS using an example TP-Link TD-W8960N:

1. Go to the router's web interface (usually at 192.168.1.1, login/password — admin/admin).
2. Go to the section Advanced Setup → QoS → Settings.
3. Turn on QoS (check the box) Enable).
4. Select the restriction type:
   • 🔄 Port-Based — by ports (inconvenient for Wi-Fi).
   • 📡 MAC-Based — by MAC addresses of devices (optimal).
   • 🌐 IP-Based — by IP (if you have static addresses).

Please specify maximum speed in kilobits (for example, 5120 kbps for 5 Mbps).

Save settings (Save/Apply).

Important: On older routers, QoS may does not work with PPPoE (if you have this type of connection). In this case, try a different method.

What to do if there is no QoS in the router?

On some budget models (for example, D-Link DSL-2500U) There is no QoS. The alternative is to use guest network with a separate SSID and bandwidth limitation (if supported) or set up restrictions at the provider level (not all operators provide this service).

3. Manual MAC address restriction

If QoS does not work or is not available, you can limit the speed for specific devices based on their MAC addressesThis method is more reliable because it is tied to the hardware, not the IP (which can change).

Instructions for Asus DSL-N12U:

1. Find the MAC address of the target device:
   • On Windows: ipconfig /all in the command line (look for the line Physical Address).
   • On Android: Settings → About phone → General information → Wi-Fi MAC address.

In the router's web interface, go to Wireless → MAC Filter.

Add the MAC address to the list and set the speed limit (eg. 2 Mbps).

Activate the filter and save the settings.

On some routers (for example, Zyxel Keenetic older models) this function is called Bandwidth Control and is located in the section Home Network.

4. Setting up a guest network with speed limitation

If you need to limit the speed for guests, but without affecting the main network, the cleanest way is to create a separate guest network with a limit. This works even on older ADSL routers, if they support Multiple SSID.

Example for TP-Link TD-W8961NB:

1. Come in Wireless → Guest Network.
2. Turn on the guest network (Enable Guest Network).
3. Please enter the network name (SSID) and password.
4. In the section Bandwidth Control set a limit (for example, 1 Mbps for loading).
5. Save and reboot the router.

The advantage of this method: guests won't have to explain why their internet is slow—they'll simply connect to a separate network. The disadvantage: not all ADSL routers support this feature.

5. Alternative methods: when the router doesn't help

If your ADSL router does not support either QoS or MAC restrictions, there are still workarounds:

Method	How it works	Cons
Provider-level limitation	Some operators (for example, Rostelecom) allow you to set a speed limit in your personal account.	Not all providers offer this service. The limit applies to the entire plan, not to individual devices.
Using third-party software	Programs like NetLimiter or TMeter may limit the speed on a specific PC.	Doesn't work on mobile devices. Requires installation on each computer.
Firmware DD-WRT/OpenWRT	Alternative firmware adds advanced QoS settings even to older routers.	Difficult to install, risk of bricking the device. Not all ADSL routers are supported.

Important: If you decide to flash your router, first check its model on the official DD-WRT or OpenWRT website. For example, TP-Link TD-W8960N supported, and D-Link DSL-2600U - No.

6. Common mistakes and how to avoid them

When speed limits are applied, users often encounter typical problems:

⚠️ Attention: If after changing the router settings the Internet is completely gone, reset it to factory settings (button Reset on the back panel). Hold it for 10-15 seconds until the indicators flash.

• 🔧 The restriction is set but does not work. → Check if the settings have been saved (sometimes a router reboot is required). Also, make sure the device is connected to the correct network (primary or guest).
• 📉 Speed ​​dropped on all devices → You may have limited the overall bandwidth of the router, not a specific client. Check your settings. QoS or Bandwidth Control.
• 🔄 After rebooting the router, the settings were reset. → This indicates faulty device memory. Try updating the firmware or replacing the router.

Another common mistake is to confuse megabits (Mbps) and megabytes (MB/s). In the router settings, the speed is always indicated in kilobits (1 Mbps = 1024 Kbps). If you want to limit it to 2 Mbps, enter 2048 kbps.

7. Checking the result: how to make sure that the restriction works

After applying the settings, you need to check whether the speed has actually decreased. There are several ways to do this:

1. Speed ​​test on target device:
   • Connect to Wi-Fi from a restricted device.
   • Take a test on Speedtest.
   • Compare with the result before the limitation.
2. Monitoring router traffic:
   • In the web interface, find the section Statistics or Traffic Monitor.
   • See how much traffic your device is consuming in real time.
6. Ping test:
   • Open command prompt and run ping ya.ru -t.
   • If the ping is consistently high (more than 100 ms), the router may be overloaded.

If the speed has not changed, go back to the settings and check:

• Is it indicated correctly? MAC address (sometimes devices have multiple MAC addresses for Wi-Fi and Ethernet).
• Did the settings reset after reboot?
• Does your router model support the selected restriction method?

FAQ: Frequently Asked Questions about Wi-Fi Speed ​​Limiting

Is it possible to limit the speed only on a laptop, but not on a phone?

Yes, if your router supports limitation MAC address or IPFind the laptop's MAC address (via the command line or network settings) and add it to the list of restrictions in the router's web interface. This will leave your phone's MAC address unchanged.

Why did the internet start lagging after limiting the speed in QoS?

You've probably set too strict a limit (for example, 1 Mbps for online gaming). Try increasing the value to 3-5 Mbps for comfortable operation. Also, check if QoS For everyone devices - sometimes this creates a queue and delays.

My router doesn't support QoS. What should I do?

There are several options:

1. Use guest network with limitation (if supported).
2. Install alternative firmware (for example, DD-WRT), if your router model is compatible.
3. Limit the speed at level provider (check with support).
4. Buy a new router with support Bandwidth Control (even budget models for 2-3 thousand rubles have this function).

How do I limit the speed for all devices except mine?

Create in the router QoS rule with a high priority for your MAC address, and set a low priority or fixed limit for other devices. Alternatively, connect your device via cable (usually, cable connections are not affected by Wi-Fi restrictions).

Will the limitation work if the router is rebooted?

Yes, if the settings are saved in the router's non-volatile memory. However, on very old models (pre-2010), user configurations sometimes become lost. In this case, the only solution is to replace the device.

If none of the methods worked, the problem may not be with the router, but with ADSL line overload On the provider's side. In this case, even a new router won't help—you'll either need to change your plan or switch to a fiber-optic connection.

⚠️ Attention: Router interface settings may vary depending on the model and firmware version. If you don't find the sections mentioned (QoS, Bandwidth Control), check the instructions for your model or contact the manufacturer's support.