Updated 2 min read
Does Your Office Need a Backup Internet Line? How Failover Works
The short answer
If your office stops working when the internet stops, you need a backup line. A second connection from a different provider, on a different path such as 5G or Starlink, plugs into your firewall, which switches over automatically when the main line fails and back again when it returns.
The main internet line doesn’t fail often. When it does, it rarely picks a good moment: a cable dug up by a construction crew across the street, a storm, an outage at the provider’s end that takes all afternoon to fix. While it’s down, an office that runs on cloud software, internet phones and online files mostly sits and waits.
A backup line is how you stop waiting.
How automatic failover works
Your office already has a firewall sitting between the internet line and your network. A business-grade firewall has room for two internet connections. The main line plugs into one port and the backup line into the other.
The firewall checks the main line constantly. When it stops answering, the firewall moves traffic to the backup on its own, usually within moments. Nobody has to notice the outage, find a password or restart anything. When the main line comes back, the firewall moves traffic back and the backup goes quiet again.
A few things behave differently during the switch:
- Calls in progress may drop. New calls work straight away on the backup.
- Video meetings reconnect. Most rejoin by themselves after a brief freeze.
- Remote connections into the office may need reconnecting, because the office’s internet address changes while it’s on the backup line.
That last point is worth planning for. If staff or vendors connect into the office from outside, we set things up so they can find the office on either line.
Pick a backup that won’t fail at the same time
A backup is only useful if it survives whatever took down the main line. Two lines from the same provider, or two lines in the same trench, can fail together.
The safest backups take a different path entirely:
- 5G business internet from T-Mobile, AT&T or Verizon arrives over the air, so a cut cable in the street can’t touch it. It’s the most common choice and the quickest to set up.
- Starlink comes down from satellites, which makes it independent of anything local. It’s a good fit where 5G signal inside the building is weak.
- Cable behind fiber (or fiber behind cable) also works, as long as the two come from different providers. They usually run on separate equipment, though they may share the same route into the building.
We test cellular signal for all three carriers inside your office before choosing, because the best carrier on your phone isn’t always the best one at your desk. Our page on business internet providers lists the providers we work with.
Test it before you need it
A backup line nobody has tested is a guess. Once it’s installed, we pull the main line on purpose and watch what happens: does the firewall switch, do the phones register again, do the important systems keep working? Then we keep an eye on the backup line from then on, so a backup that has quietly stopped working gets fixed before the day you need it.
If you’d like to know whether a backup line makes sense for your office, and which one would work best at your address, send us your address. Our guide to business internet options covers choosing the main line.
