In short
A dual internet connection uses a router with two outputs, for example fibre and 4G or 5G, that constantly checks whether the main one works and, if it fails, switches traffic to the backup within seconds. It can also share traffic between both. Use different operators and protect critical services first, such as the card terminal or IP telephony.
Operating modes
| Mode | How it works | When it fits |
|---|---|---|
| Failover | The second line is used only if the main one fails | The most common: 4G or 5G only uses data during a fault. |
| Load balancing | Traffic is shared between both lines | When both are fast and there is no data cap. |
| Per service | Each service uses the chosen line | For example, telephony on one line and browsing on the other. |
What to consider
- Different operators, so one fault does not affect both lines.
- Outdoor antenna for 4G or 5G if indoor coverage is weak.
- A real internet check, not just whether the cable is connected.
- Phone alert when a switchover happens.
- Backup power for router and modem, or a power cut defeats the dual connection.