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For Wake-on-LAN (WoL) and Wake-on-Wireless (WoW) computer must be only suspended or could be completely powered off? Assuming, the PC box is plugged into mains all the time.

Are there any differences between operating systems?
I am mainly interested in Wake-on-Wireless (WoW) on Linux.

I always assumed that, WoW, if not also WoL, requires computer to be only suspended to RAM, or some other low power state, but it cannot be fully switched off, or hibernated. During suspend to RAM computer needs obviously some power intake to keep memory content, so wifi could be powered too, powered enough to react on magic packet.

On one hand tutorials, like on HowToGeek or LifeWire, make it sound like suspend is not necessary.

On the other hand Linux WoW documentation clearly says: Wake on Wireless is a feature to allow the system to go into a low-power state (e.g. ACPI S3 suspend) while the wireless NIC remains active and does varying things for the host, e.g. staying connected to an AP ... This sounds like WoW to work, PC cannot be switched off and system has to have working suspend/resume.

That is not good news to me. After a month of struggling with getting my box to suspend and resume under Linux I am about to give up; I suspect the Broadcom proprietary drives form my bcm4360 are suspend-unfriendly.

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3 Answers 3

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As far as I know and tested (only WOL), the computer does not need to be in "standby", can be also shut down completely, but still powered (for example, a Windows PC, can be Shut Down/Turn Off and will wake-up from the "magic packet" of WLAN).

Also what I've come across was that it DEPENDS on the WOL implementation in the device you're trying to wake, because I had some that will only wake if they where previously started then shut down and never let without power, and had some (fewer) others that did not need to had this routine before, so once plugged in to the power, not need to start it manually, the WOL worked just fine. Again, those were fewer in number, and usually very good brands (example Apple, HP, can't recall just now what models were the devices exactly).

As of WOW, I have no experience at all and can't comment, other than if I think it through, I believe a Wireless Network Adapter needs WAY more power to have the antenna up&running catching signals, than the wired adapter that need just the stand-by power (five volts?!?);

So if I would be to guesstimate the WOW part of it, I would summarize as this:

  • WOL - no need to "stand-by" the device, the device can be powered off
  • WOW - the device must be in "stand-by" not in power off
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  • From all information I was able to gather so far, from that little information I was able to gather, you are most likely right. Sadly. WOW seems to be much less fickle and definitively less supported generally.
    – Espinosa
    Apr 10, 2019 at 22:57
  • If you think about it little deeper (of how the things actually work in WOW situation), it is quite normal like this, and for sure will not be much of a "hype" since it is not actually a "waking up" what's happening for WOW, since most of the system is already running to keep the wireless card active. That's why no support, cause it is actually not a "functionality", since the system would not make much of a difference between waking up by a mouse movement (for example), or a keyboard pressed, or a wireless network signal; "trigger" is different, but the action is the same!
    – Felix_ro
    Apr 11, 2019 at 10:04
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depends on the implementation:

"Real" WOL is supposed to be handled by the BIOS and works with a shutdown

It might also be possible to configure inside an OS to configure "Wakeup via LAN" which will only work from hibernate

I have however no experience with WOW

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From Intel:

Wake-on-LAN (WoL) is a hardware/software solution that wakes up your computer remotely from a low power mode or off mode. The computer must have an Internet connection and be plugged in to power for WoL to work.

Devices that do support Wireless Wake-on-LAN only support wake from system sleep states S3 or S4.

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