Friday, March 30, 2018

Optus Cable with Google Wi-Fi

We had Optus Cable installed yesterday, replacing an aging ADSL connection. We already had Google Wi-Fi installed, replacing a complicated setup consisting of a Linux-based firewall and multiple access points, but ADSL had become painful, with disconnections whenever it drizzled, let alone rained, and one phone line not working at all (perhaps disturbed by a linesman while trying to get the ADSL fixed).
Up with this, I shall not put!

I had no intention of downgrading our Google Wi-Fi setup with the somewhat primitive devices Optus supply, so the problem was to get the combination working. Google Wi-Fi can lose some functionality if hidden behind another router, so I had googled for information on the Optus-provided devices to see how they performed. Posts on discussion boards suggested the Netgear CG3000 could be configured as a bridge via some barely-documented settings, while the Sagemcom devices should be avoided at all costs. With that in mind, I selected a plan that provided the CG3000 and figured I would let the Optus technicians get it working and then figure it out. I also took the precaution of buying a spare CG3000 - just so I could replace a Sagemcom if worse came to worst, or perhaps have one configured the way I want and the original to put back into place if necessary.

In the end, there was far less drama than expected. The Optus techs turned up with a Netgear CM500V modem and a separate Sagemcom 3864V3 router. I let them install it, connected to it via my laptop to show it was all working, and bid them adieu.

Then I unplugged the Sagemcom and put it back in the box and performed the following procedure:
  1. Switch off the CM500V. This is necessary, as the modem remembers the MAC address of the router it is connected to and will not talk to the Google Wi-Fi router without a reboot.
  2. Switch the CM500V back on again. It may take a few minutes to connect, so get it started while you're doing the rest of this procedure.
  3. Unplug the Google Wi-Fi router from the ADSL modem.
  4. Check the Google W-Fi router has realised it is offline - it should show a pulsing amber light.
  5. Turn off mobile data on your phone, then run the Google Wi-Fi app and go to Settings -> Network & General -> Advanced Networking -> WAN. The WAN settings are not editable unless Google Wi-Fi is offline and your phone is talking to it directly on the wireless LAN.
  6. Change the WAN settings to "DHCP" and tap "Save".
  7. Check the CM500V - the Power, Downstream, Upstream and Internet LED's (the top four) should all be solid green by now.
  8. Plug in the Ethernet cable from the Google Wi-Fi WAN port to the modem. Give it a few seconds - the Ethernet LED on the CM500V should turn green and the Google Wi-Fi router will get its WAN IP address via DHCP and should settle down to a stable white light.
  9. Phew! That's better!
  10. Go back to the Google Wi-Fi app Shortcuts page, tap "Network check" and then "Test Internet". Marvel at the impressive speed test result!

The NBN HFC Internet connection box sits, forlorn, on the wall of our house while nbnco tries to figure out how to get DOCSIS 3.1 up and running on the cable. We just couldn't wait that long in the end. However, I expect this procedure should work just fine with an NBN cable modem.

Final caveat: I haven't tested the CM500V with a phone, since we have an Asterisk VoIP setup. But I've no reason to suspect switch to the Google Wi-Fi setup will affect phone operation in any way.