Work out what an outage costs you
Start with a simple question: if the internet went down at 10am on a Tuesday, what would stop? For most offices today the answer is almost everything, from email and Teams to cloud accounting, phones, EFTPOS and the booking system. Multiply the number of staff by an hour of their time and add any lost sales, and you have a rough cost per hour of downtime.
Fibre outages are not common, but when they happen they can be long. A digger through a cable in the street, damage after a storm or a fault in the building can take a site offline for a day or more while repairs are arranged. A backup connection turns that day into a few seconds of interruption.
Option one: a second fixed connection
A second fibre service from a different provider gives the most capacity and the most consistent performance. The catch is that both services often share the same physical path into the building and the same fibre in the street, so a single cut can take both down. Ask about physical diversity, meaning a separate route, but expect it to be limited or expensive at many addresses.
Fixed wireless from a local provider can make a good second fixed connection, because it uses a completely different path through the air. It needs line of sight to a tower and may involve a small dish on the roof. It suits rural and semi-rural sites well, and some urban locations.
Option two: 4G or 5G mobile
A business-grade 4G or 5G router with an external or well-placed antenna is the most common backup for small offices. It uses mobile networks that are completely separate from the fibre in the street, can be installed quickly and costs relatively little per month on a backup-sized data plan. Coverage and speed vary a lot by location, even within a building, so test signal strength before committing.
Choose a data plan that suits a backup role, with enough allowance for a full day of office use if the fibre is down. Ask what happens if you exceed the allowance. Using a different mobile network from your staff phones can be wise, so that a single mobile network outage does not take out both your backup and your phones.
Option three: Starlink
Starlink's low-orbit satellite service has become a realistic backup, especially outside the main centres where mobile coverage is weak or where there is only one fixed provider. It needs a dish with a clear view of the sky, a mounting position agreed with the building owner and a power supply. Speeds are usually good, with latency low enough for video calls.
Business plans are available, and a portable or lower-usage plan can work as standby capacity. Because it relies on nothing in the street, it is a strong choice for sites where losing connectivity is a serious problem, such as rural clinics, farms, remote branches and businesses that run their phones over the internet.
How automatic failover works
The backup connection plugs into a second port on a business firewall. The firewall constantly checks the main connection by testing whether it can reach the internet, not just whether the cable is plugged in. When the checks fail, it moves traffic to the backup within seconds and moves it back once the main line recovers. Staff may notice a brief pause and some calls may drop, but work continues.
Some firewalls can also share load across both connections when both are up, or send specific traffic, such as phone calls, over the line that is performing best at that moment. Those features are where SD-WAN services come in for larger or multi-site businesses. For a single small office, simple failover is usually all that is needed.
Do not forget power and testing
A backup internet connection is useless if the firewall, switch and backup router lose power. Put them all on a UPS sized to keep them running for at least the length of a typical short outage. Note that the fibre equipment in the street and the mobile towers have their own backup power, but it may not last through a long regional outage.
Test failover regularly by unplugging the main connection for a few minutes after hours. Confirm the switch happens, that phones and key applications work over the backup, and that you receive an alert. A failover that has never been tested is a failover you cannot rely on. Write the steps down so anyone can repeat the test, and check the backup data allowance afterwards.
In short
- Estimate what an hour of downtime costs before choosing a backup.
- A second fibre service may share the same street path as the first.
- 4G or 5G is the quickest, cheapest backup where coverage is good.
- Starlink suits rural sites and businesses where outages are costly.
- Put the firewall and backup router on a UPS and test failover regularly.