Skip Navigation
Individual Climate Action @slrpnk.net activistPnk @slrpnk.net

(energy savings) Turn off Wi-Fi, cap ethernet, hardwire uplink, reverse-tether your phone

My SOHO router has a some “green” configuration features to reduce energy consumption:

  • (wi-fi) A scheduler for the Wi-Fi radio to turn it off automatically during times it won’t be used. (dd-wrt has this)
  • (wi-fi) A power level throttle (10%, 20% 50%, 100%) so you are not amplifying the signal beyond the range that you need. (dd-wrt has this)
  • (wi-fi) A bezel button on the chassis so you can easily turn Wi-Fi on and off without entering the configs.
  • (wi-fi) choose an SSID that does not feed an oil partner (details).
  • (ethernet) A per-port choice of 1 Gbits/sec or 100 Mbits/sec. Apparently capping it to 100 Mbits/sec saves energy because they’re calling it a green setting. I’m a bit surprised the savings would be notable enough to justify the option. But I doubt my uplink has more than 100 Mbit/s anyway so I capped my ports.

Beyond the router:

  • (uplink) Since GSM radios use 30 times more energy than a wire, obviously getting your internet over cable, dsl, or fiber are more energy efficient than GSM (and probably any wireless uplink for that matter).
  • (web browsing) Disable image loading in the browser because images are much heavier than text. Most images are junk anyway.

reverse tethering

I’ve started reverse-tethering my phone over USB, so I can keep Wi-Fi disabled on both my router and devices most of the time. This option is threatened though, because the Android tool Gnirehtet is no longer maintained.

When Gnirehtet eventually dies, theoretically it’s possible to use openVPN for reverse tethering. But the ovpn project has decided to scrap the clearnet option under the naive view that there is no use-case for an unencrypted tunnel. If you can’t get cipher compatibility between your mobile device and your PC, it will not work.

4

You're viewing a single thread.

4 comments
  • This...won't do anything in an average household. A consumer grade router is quite efficient, unless you just turn off the entire device

    A per-port choice of 1 Gbits/sec or 100 Mbits/sec. Apparently capping it to 100 Mbits/sec saves energy because they’re calling it a green setting. I’m a bit surprised the savings would be notable enough to justify the option.

    It doesn't, unless you've repurposed a computer as a router, then the CPU has to do the heavy lifting of packet handling. The faster you go, the more it has to work, but any consumer grade router uses ASIC chips dedicated for Ethernet handling.

    It's true cellular uses considerably more power because of the distance so you should use the far more efficient and local WiFi

    Disable image loading in the browser. Most images are junk anyway.

    Great for speeding up browsing on a limited connection, pointless for energy savings

    Btw your reverse tethering option probably stopped being maintained because that is now built in to Android

    • Great for speeding up browsing on a limited connection, pointless for energy savings

      We know from this research that video conferencing has a notable emissions impact, which could only be a consequence of energy consumption. Bandwidth doesn’t just cost energy at home but also all the servers and equipment that carry the payload upstream to the other end.

      Video conferencing is like sending low resolution images with many diffs. Still images in a browser would be higher res (and bigger with higher pixel addressability), though much fewer in numbers, but still considerably more consumption than text.

      Btw your reverse tethering option probably stopped being maintained because that is now built in to Android

      What happens on the server side with recent versions? PCs don’t normally expect network traffic on USB (edit: well, not sure about windows, but not linux AFAIK). Gnirehtet is installed on the PC and it uses ADB to run the mock VPN on the Android.

      (edit) Looks like on the linux side it’s just a matter of setting up a bridge with no extra software. But for the Android side every approach I find calls for an app. Does anyone know which Android version introduced built-in reverse tethering?

      • There's a huge difference between video and images, video is always expensive bandwidth-wise and intense. I can definitely see it having an emissions impact. Nearly all the images you'll encounter on your day to day browsing otoh is tiny and heavily compressed, bigger than text, but not enough to have a notable impact like video can.

        As far as reverse tethering, it's under USB "internet" in settings, once that's going you go back to network connections in Windows and you'll have the computers Ethernet and another Ethernet that your phone is emulating. Select your computer Ethernet connection, right click properties, sharing tab and share to the other to bridge the connections

        • Nearly all the images you’ll encounter on your day to day browsing otoh is tiny and heavily compressed, bigger than text, but not enough to have a notable impact like video can.

          I’ve noticed that people are quite bad at choosing the right compression algo for the job. And Wired mag concurs. SVG should be favored, but JPEG, PNG and GIF dominate. And even if you don’t have a vector graphic to start with, people often make the wrong choice between the three.

          “reducing emissions can also be as simple as limiting the number of images that feature on each web page.”

          -- Wired

          “Images are the single largest contributors to page weight. The more images you use and the larger those image files, the more data needs to be transferred and the more energy is required,”

          -- Vineeta Greenwood, account director at design agency Wholegrain Digital

          edit: I just realized this is another problem Cloudflare brings us. When web admins opt to offload their job onto Cloudflare, they have less incentive to ensure their website is lean. The Wired article says web pages have quadrupled in weight since 2010. I’m sure much of that can be attributed to Cloudflare facilitating the bloat.

          As far as reverse tethering, it’s under USB “internet” in settings

          So you navigate this way: settings » USB internet? (my ~6+ y.o. device does not have USB anything in the top level)

          Is the reverse tethering switch in a different place than the forwards tethering switch in your case? I found this well-written guide by someone who favors configs over software for this. Unfortunately the article has no date but it was archived in Oct.2020. He says root is required as well as terminal commands, but since it was possible with root for a long time I assume you’re saying recent versions make the option available without root. The article mentions this path:

          Settings - Wireless & networks - Tethering & portable hotspot

          and that’s what I have. There is a “USB tethering” boolean in the Tethering & portable hotspot page. I have always figured that option was strictly for forward tethering. And to reinforce that assumption, when Gnirehtet is running that “USB tethering” switch is in the off position (but perhaps because it uses the phony vpn approach). The article seems to be using that boolean for reverse tethering, unlike Gnirehtet.