ethernet - Wireless or wired LAN: Which consumes less power?

07
2014-07
  • Elrond

    I have a printer that has Ethernet LAN and Wi-Fi WLAN. The printer is seldom used, so I'm interested in minimizing idle power consumption.

    My Wi-Fi AP is on anyway, so that's not interesting.
    My first guess would be that a wired LAN connection would use less power, because there's not so much power lost "in space". But on the other hand, I vaguely remember that at least gigabit Ethernet sends a constant signal or something, while Wi-Fi only sends something if there is something to send?

    So how should I connect my printer to minimize idle power usage? If Ethernet, would it make any difference if I reconfigure the ethernet link to 100 Mbit/s or even 10 Mbit/s?

    • Answers
  • Rabarberski

    Your question is still rather unclear. However, I assume you are you interested in whether you should use, from a power consumption point of view, your printer's wifi or the wired ethernet.

    To be sure you should measure it with a power meter, but I think it won't make much of a difference, as I would be surprised if the printer is optimized towards this. Stating the make and model would also help. Also, you should check if you can disable the wifi on your printer. If you can't then it's even more likely that it won't make a difference.

    IMO, if you're interested in saving power (good!), just turn off the printer when you don't use it (which seems to be often as you say it's "only used seldom"). As a bonus: walking to and reaching out to turn on the printer is a good exercise as well.


    • Related Question

    router - If a computer is connected to internet via wireless and lan both, which way Internet traffic would flow?
  • Questioner

    How does this actually work? How different ip addresses on ethernet adapter and wireless adapter are handled for internet data? I know these ip are translated in NAT table but the whole process involving ethernet and wireless adapter together is not clear to me.


    • Related Answers
  • whitequark

    If (for packet that is sent by your machine) destination is not in LAN (DestAddress & Netmask != YourLANAddress & Netmask) it will be redirected to your default gateway, and if both of your devices are connected to the same network (if they have IP addresses belonging to same network actually; it is determined by the same algorithm) packet will travel through device with a lower metric.

  • Ether

    It's entirely dependent on how your network interfaces are configured. The usual place where this is done is in a routing table, which lists the ethernet addresses of the adjacent nodes. Both might be used at once, or just one, depending on what this table says.

    For example of one such configuration in MacOSX, see my question here: http://superuser.com/questions/89994/how-can-i-tell-which-network-interface-my-computer-is-using

  • IAbstract

    I believe that one of the devices is set as a 'default' device. The other will basically sit there and do nothing. Double-click the little tray icon for your internet connection, it will tell you which one it is using...

  • user13141

    From my experience in Windows XP (from having the network activity icons in the notification area) it seems smart enough to use the faster LAN connection as soon as it becomes available. Turn on the icons and see for yourself.