Do I need to enable TWT on my WiFi6 router? It’s true that it saves power, and it’s true that the door lock notification is late.

Last month I replaced my neighbor's router, and he asked a very practical question.: Why does the thermometer and hygrometer at home, which has two AA batteries, still have to replace the batteries every two months after switching to WiFi 6? I went backstage and looked around, and saw the one hidden in the wireless advanced settings. TWT , then I remembered that I had turned this switch on for two weeks and turned it off twice.

TWT is not a speed-increasing switch. People who expect that WiFi will become faster after turning it on can skip it directly. It manages when and how often the device wakes up. Turn it on right, battery devices such as smart homes and mobile phones can save some power. ； If it is turned on incorrectly, the door lock notification will be late, and some old devices will not be able to connect. This article explains clearly the judgment method that troubled me.

What does TWT care about? Don’t be frightened by the word “wake up” yet.

The full name of TWT is Target Wake Time, which is generally translated into Chinese as Target Wake Time target wake time . The name sounds like an alarm clock, but it is actually an alarm clock: The router and the device agree on a schedule first, and the device wakes up at that time to receive and send data, and sleeps at other times. It’s not that the WiFi keeps dropping, it’s that the device itself rarely opens its eyes.

The problem with old WiFi is that the "checks" are too frequent. The router's beacon broadcasts every 100 milliseconds or so by default. Even if the device is not working, it has to wake up from time to time to listen. Listening to it once doesn't consume much electricity, but being awake like this 24 hours a day and 365 days a year is too much for small things like sensors, door magnets, and thermometers and hygrometers that rely on batteries. TWT is equivalent to changing "always listen to orders" to "according to the duty schedule", and the device sleeps longer.

There's a key thing to remember here: What TWT saves is the power of the terminal equipment, not the power of the router, nor the speed of the broadband. . When you turn on your mobile phone or laptop while it is plugged in, you will basically feel no change. ； The real benefit is the stack of battery-powered IoT devices. If you want to improve your internet speed easily, you have to read OFDMA and MU-MIMO article , that is what can be transmitted by multiple devices at the same time.

What does the switch look like in the background? Huawei, TP-LINK, and Xiaomi have different names.

Don't search all the backend based on a Chinese name. If you can't find it, it doesn't mean it doesn't exist. Below are three common names that I have encountered in my hands and the machines around me.:

The Huawei one is the most confusing. It does not write the three letters TWT, but "reduces the sleep power consumption of Wi-Fi 6/Wi-Fi 7 terminal equipment." I almost dismissed it as an advertising switch. What is more important to note is that Huawei defaults to off , the official reason is that some old terminals cannot scan or connect to WiFi when they are turned on. TP-LINK's Archer AX73 is also turned off by default, so you have to turn it on yourself.

So don’t assume that “new routers should be turned on by default”. Among the performance switches of WiFi6, OFDMA and MU-MIMO may be on by default, but many TWT machines are off by default. I was confused by this contrast at first, but later I realized that the manufacturer was exchanging compatibility with older equipment for power saving.

I drove it for two weeks: You can feel the power saving, and you can also feel the delay.

The first time I opened it was on Huawei AX3 Pro. At home, there is a Mijia temperature and humidity meter, a door sensor, and a smart lock, all hanging under 2.4G. I ignored it for the first two days, but when I went out on the fifth night, the door lock notification was half a beat slower than usual, and the longest time it took was almost a second. I initially thought it was the door lock that was blowing on its own, so I tried reconnecting and changing the battery repeatedly, and finally I suspected the TWT that had just been opened.

After turning it off, the door lock notification returns to the original speed, which basically arrives within half a second. I later changed to just leaving the TWT on for observation, and no longer struggled with the door lock. The result is indeed both ends.: The thermometer and hygrometer lost power slowly, but the slowness was not quantified enough to make me willing to delay the replacement of the door lock. ； Door magnets, door locks, etc. need real-time feedback equipment, I didn’t stay with TWT in the end.

We have to talk about the ugly things here.: This is not a laboratory test. The WiFi environment at home is different every day. 2.4G interference from neighbors’ microwave ovens and express cabinets will affect the results. But TWT will make the device wake up less, which means "only come when you have something to do" and the response time will become longer. This direction is certain.

Category 4 equipment is suitable for use. I advise you not to use Category 3 equipment.

After turning it on for two weeks and turning it off twice, I set a rough rule for myself: First look at what the device relies on for power supply, and then look at whether it needs to be powered back in seconds.

The order of judgment is actually just one sentence: First ask if it is battery powered, and then ask if something will happen if it is two seconds late. Only when both are satisfied is it worth opening. The door lock and smoke detector obviously do not meet the second requirement ； If the thermometer and hygrometer meet both conditions, it will smell better when turned on.

If there is a dedicated IoT network at home, I would simply put these sensors in a separate 2.4G network, and then only enable TWT for this network. This way you don't have to gamble with the door lock. I used to do network splitting The article about 2.4G and 5G As mentioned in , the idea is the same, which is to physically separate the power-saving and real-time devices.

How to turn it on, how to see it after turning it on, don't take "it seems to have saved power" as a conclusion

Do two things before you start. First, upgrade the router firmware to the latest version. Many compatibility fixes in the WiFi6 generation rely on firmware. Turning on TWT with old firmware will cause you trouble. Second, write down the current equipment list. At least observe the response speed of door locks, smoke detectors, and cameras for a day, otherwise you will not be able to check if there are problems after opening them.

After you find the entrance, open it, save it, and then don't leave in a hurry. Let the sensor be reconnected first, and then verify in the following order::

The door lock and door sensor notifications are still not followed, especially when they are triggered after coming back from outside.
1. For slow data devices such as temperature and humidity meters and water immersion devices, refresh the app to see if you can get them normally.
2. Can the oldest mobile phone or smart speaker at home find WiFi and connect to it?
3. Turn off the mobile phone's WiFi and then turn it on again to confirm that "you can see the signal but keep spinning in circles" will not appear.

My experience is that compatibility issues with older devices are most likely to be revealed in the first one or two days. ； The delay problem will not appear until the door lock and door sensor are triggered by you several times. Just click on the switch to see the page is normal, it doesn't count.

If you have a device that supports TWT after opening it, the change in battery life does not need to be accurate to a few percent. It is enough to see that "there has not been much power loss this week." If you want to see the details of the negotiation, you can go to The article about WiFi6 and WiFi7 , it is said that the mobile phone negotiation rate and the actual experience are two different things.

If these three symptoms appear, turn off the machine and don’t hold on to it.

There is no such thing as "must turn on" TWT, especially when you use a mix of old and new equipment at home. I left myself three hard signals to turn off the switch.:

Someone followed TWT MLO for WiFi7 Confused, I think they are all new switches for WiFi6/7, and turning them on will always make them more advanced. In fact, MLO manages the simultaneous connection of mobile phones to 2.4G and 5G to improve the intranet speed, while TWT manages the sleep of IoT devices. The two directions are not connected. When something really goes wrong, it's better to turn it off than to let a power-saving switch slow down your home's door locks and cameras.

My current home situation is: The temperature and humidity meter and water immersion sensor are still on TWT, and the door locks and smoke detectors are not on this network. Power saving and real-time, these two needs naturally fight, taking apart the tube is more comfortable than choosing one of the two.