All heist films have a contingency plan. Your checkouts should too!
If your Internet Service Provider (ISP) goes down, your cards will not clear and queues will start to build. If you have just one cable issue, all your registers will go down. With a cellular failover, everything will be protected. It is one of the most practical things to add to your business' connectivity.
Why Will Your Registers Suffer During an ISP Outage?
Most registers today require an internet connection. Card payments will not work if there is no active connection to the processor. Cloud POS will not work if you cannot connect to get prices, stock and receipts. Loyalty and gift card checks will not work either.
Some registers have offline functionality, but this is usually limited. Many have a limit on offline sales or no fraud checks. Some will not allow any sales. Your staff will have to take cash.
It is easy to see the benefits of less downtime. Take the amount of sales you get per hour at peak times. Multiply this by the length of your last outage. This will usually be higher than the cost of having a failover.
How Cellular Failover Works
This provides another route to the internet using 4G LTE or 5G. There are three parts.
- Primary: This is your normal fibre, cable or EFM circuit.
- Failover: This is either a cellular modem or a router with a cellular radio built in.
- Failover Logic: This is the software that monitors your primary connection and routes traffic if there is an issue.
Every few seconds your router will ping a public address with a small packet of data. If it fails multiple times in a row, it will route traffic via cellular. Once the primary connection is back, it will route back.
This usually happens very quickly. Often cashiers won't even notice.
Choosing the Correct Kit
There are 3 common options.
| Option | Best For | Trade Off |
|---|---|---|
| Built-in Cellular Router | Single Stores | Radio and Router in 1 |
| Cellular Modem | Existing Router | Extra Device and Power |
| Dual SIM or Carrier Gateway | Multi-site Brand | Higher Cost and Better Coverage |
Within retail, you want a few main features.
- Dual SIM, so you can have 2 carriers.
- WAN failover with adjustable health checks.
- Remote management, so your IT team can see the status.
Your antenna will be important. Many stores are within metal buildings or deep into a mall. If the signal isn't strong, your failover won't work. Using external antennas will provide a signal outside of the walls.
Common Mistakes With Failover
Whilst failover is simple, it can be tricky in practice.
- Registers not on the correct network: Payment terminals can be set to a static IP. If they are pointing to the old gateway, they won't follow the traffic. Use DHCP reservations or update your gateways.
- Carrier grade NAT: Many cellular providers will give you a private IP. This means you won't be able to receive any connections. Cloud POS will generally work. Remote desktop, VPN servers or some camera systems won't. Ask your carrier for a static or public IP.
- Poor health checks: If your router is only pinging your cable modem, it won't know if there is an issue upstream. Ping a real location, such as a public DNS or your processor.
- No power backup: Your cellular router won't do anything if it loses power. Place your router, modem and switch onto a small UPS. Also include your payment terminals.
- Too much on your failover: Cellular connections can be restrictive. Uploading cameras, software updates and guest wifi can use up your plan in an hour. Create rules to ensure only critical traffic is going through.
Data Plan Sizing
Card payments won't use much data. Even in a busy store, you can process thousands of sales with a small plan. Cloud POS and receipt syncing will use a little more, but again it won't be much.
If you are adding other devices, you need to calculate how much data you need. Do the following.
- List out the devices you need to have working.
- Work out how much data they usually use in a day.
- Add a buffer of at least 50%.
Set a Quality of Service rule. Payment should be the highest priority. Block everything else.
Testing
A failover that has never been tested is a guess. Try testing it live at least twice a year.
- Unplug your primary connection during a quiet time.
- Time how long it takes to switch over.
- Do a card sale.
- Check your receipts, gift cards and any cloud tools.
- Plug your line back in and confirm it is back.
Write down the results. Keep a quick checklist at your front counter. Your staff should know what a failover looks like and who to contact if it doesn't work.
The Future
Cellular failover is improving every year. 5G networks mean faster speeds and less latency. With eSIM support, changing carriers is easier. Some routers now support dual carriers, so they will always have the best signal.
With SD-WAN tools, multi-site brands can manage everything from one dashboard. Your teams can see which stores are on failover and why. This means outages are no longer a surprise.
The aim is that customers never know your ISP went down. If your registers are still ringing, then your failover has worked!