Since purchasing my home in the Baltimore area, I’ve been struggling with one thing: not being redundant enough. If you are from an IT background, you know what I mean. Each server is powered by one PSU to house power. The other PSU connects to a UPS. Your uplinks to your IDFs are port-channeled and paired. Everything – and I mean everything – is better when there’s a backup.
Setting the Stage
This summer, we moved into our new home, and I had a bunch of network gear I was installing, but I was still a few weeks away from the internet service being installed. I knew what service I was going to get. I was confident my network gear was going to play nice. Despite that, at that moment, I was at a standstill.
While using my phone as a Wi-Fi hotspot (ugh) I was browsing around for a solution and happened upon a reddit thread (sadly, I don’t have the link) where someone claimed they used a 5G modem and a (*gasp*) free data-only card from their mobile phone provider. I looked into it, and it turns out Google Fi offered such an option. I continued to read the thread. It was meandering and convoluted at best. I remained determined that this could be a possible solution. I looked around, added a cellular modem to my shopping list and ordered a data-only SIM from my provider.
About a week later, I had both in my hand and it was time to set it up and test it out. Now, the model I got (the MC7010CA from ZTE) wasn’t overly user friendly, but I was an experienced IT guy, so I’m sure it was fine. The instructions seemed simple enough, plug in the SIM, plug in the injector, profit. That’s not exactly how it went. In retrospect, I should have gotten a better modem, but I had already hemorrhaged so much money on the other network gear and home updates that I got what I got. In hindsight, I should have looked at industrial installation options, but that also includes a higher pricetag.
My ISP before my real ISP
Google’s Fi service is a leased service. They rely on other providers’ towers to do the work. As a result, I needed to change the APN information. Thankfully that information was provided to me after the activation of the SIM card. Call the profile “Google Fi”, set the APN to “h2g2” and no manual authentication. Easy.
I set that up, plugged in the injector, put a laptop on the far side and I was online. Hazzah!
Then I moved the modem down to the basement and plugged it into my WAN link on my Ubiquiti Dream Machine Pro Special Edition (new for this house) and – after a tense reboot of the modem – the whole home was online. This was great!
There was only a week until my new ISP was being installed, so I was good until then.
Failover Internet Fail
The problem came when said internet connection came online. My Dream Machine didn’t care one way or the other, so I shut it down (which powered off all the APs around the new home), swapped the cabling over to the new provider, and booted everything back up.
After boot, I was back online running at my desired speeds. I plugged the wireless modem into the secondary WAN port, configured it for Failover and life was good. The actual problem didn’t rear its head for a while.
The Reason for Redundancy
A few months ago, there was an outage of internet in my area which appeared to be centered on my provider. Oh, this is fine, my provider is having a problem, the backup will just take over. But it never did, and I never tested it. (Bad IT guy!)
There were two settings (both in the same area) on my modem I needed to change for it to play nice as a failover. The first thing I needed to change was the mode to “Wireless broadband” from “Bridge mode.” Now, this doesn’t make any sense to me because a bridge is just that and everywhere else I’ve seen in the past, you want the “bridge” to connect your existing router to a modem. I don’t know why my internet tests worked in Wireless broadband mode and not bridge, but there it is. If anyone has a legitimate answer, I’m all ears because I couldn’t find anything online to back this up.
I also elected to turn off DHCP. It was just easier to not worry about a stray DHCP server on my network, so I assigned a static /30 address on the Dream Machine and modem side.
Why am I writing this? For two reasons:
- Other people may find this information useful.
- In case I ever have to factory reset the modem because there’s no “save backup” option for this device.
And that’s it.