How to set up and troubleshoot a 4G/5G mobile broadband failover for your business internet connection

Network & Internet KB-505

Summary

This guide helps you troubleshoot and resolve: How to set up and troubleshoot a 4G/5G mobile broadband failover for your business internet connection. Follow the steps below to fix the issue.

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Common Causes

A reliable internet connection is essential for any modern business. When your primary NBN or fibre link drops out, a 4G/5G mobile broadband failover can keep your operations running by automatically switching traffic to a mobile network. This guide explains how to set up a mobile broadband failover using either a USB dongle or a portable hotspot, and how to troubleshoot common issues.

Before You Begin

You'll need a few things in place before configuring failover:

A router that supports mobile broadband failover (most current business-grade routers do, including models from TP-Link, DrayTek, Cradlepoint, and MikroTik)
An active mobile broadband SIM with a data plan suitable for business use
Either a 4G/5G USB modem dongle or a portable hotspot device with ethernet output
Admin access to your router's configuration page
Your router's IP address, username, and password (usually printed on the device or in its manual)

Check your mobile plan's data allowance before relying on failover for extended outages. A standard NBN connection can use hundreds of gigabytes per month, so consider an unlimited or large-data business SIM for failover purposes.

Quick Fix Steps

If your failover isn't kicking in, try these checks first:

Confirm the USB modem or hotspot is powered on and has mobile signal.
Verify the SIM is active and has credit or data remaining.
Log into your router and confirm the mobile broadband interface is enabled.
Reboot the router with the mobile device connected.
Test by disconnecting the primary WAN cable and checking whether traffic flows through the mobile link.

Detailed Setup Instructions

Option A: Using a 4G/5G USB Dongle

Insert your mobile broadband SIM into the USB dongle and connect it to your router's USB port.
Open a browser and navigate to your router's admin page (commonly 192.168.0.1 or 192.168.1.1).
Log in with your admin credentials.
Navigate to the Network, WAN, or Internet section, depending on your router model.
Look for a secondary WAN, USB modem, or 3G/4G/5G option and enable it.
Enter the APN details provided by your mobile carrier. Common Australian APNs include:
- Telstra: telstra.internet
- Optus: yesinternet or connect
- Vodafone: live.vodafone.com
Set the failover mode to Failover Only or Backup so the mobile link only activates when the primary connection drops.
Save the settings and reboot the router.

Option B: Using a Portable Hotspot with Ethernet Output

Power on your portable hotspot and confirm it's connected to the mobile network.
Connect the hotspot to your router's WAN or USB port using an ethernet or USB cable, as supported by your device.
Log into your router's admin page.
Navigate to WAN settings and select the appropriate connection type (usually Dynamic IP or DHCP).
Enable failover mode and assign the hotspot connection as the secondary WAN.
Save and reboot the router.

Configuring Failover Behaviour

Most business routers allow you to fine-tune when failover occurs:

Failover trigger: Set the router to switch to mobile when the primary WAN is unreachable for a set period (commonly 30 to 60 seconds).
Failback trigger: Configure the router to return to the primary connection once it's stable for a defined period (often 5 to 10 minutes).
Traffic prioritisation: If your router supports it, prioritise critical traffic such as VoIP or VPN over the mobile link during failover.

Some routers refer to this feature as "Dual WAN," "WAN Failover," or "Load Balancing with Failover." Check your model's documentation for the exact terminology.

Troubleshooting

Mobile Link Won't Connect

Confirm the SIM is seated correctly and not PIN-locked.
Verify the APN settings match those supplied by your carrier.
Check that your router's firmware is up to date, as older firmware may not support newer 5G modems.
Test the SIM in a phone to confirm it has active service.

Failover Isn't Activating

Confirm the failover feature is enabled in your router settings.
Check that the mobile interface is set as a secondary or backup WAN, not the primary.
Increase the failover detection timeout, as some routers switch too quickly during brief primary link hiccups.
Review the router's system logs for clues on why failover didn't trigger.

Slow Speeds on Mobile Failover

Check the signal strength on your mobile device. Poor signal will dramatically reduce speeds.
Reposition the router or hotspot near a window or external wall for better reception.
Consider an external 4G/5G antenna if indoor signal is weak. Many USB modems and hotspots support antenna upgrades.
Limit bandwidth-heavy activities during failover, such as cloud backups or large file syncs.

Connection Drops Repeatedly

Some mobile networks disconnect idle sessions after a period. Enable "keep-alive" pings in your router to maintain the connection.
Check whether your data plan has a session timeout or fair-use policy that may be interrupting the link.
Update your router's firmware and modem driver if available.

Mobile failover is a backup, not a replacement for a primary business connection. Latency is typically higher on 4G/5G, which can affect real-time applications like voice calls and remote desktop sessions. If you depend on these services, discuss a dedicated business-grade solution with your account manager.

How to connect to Wi-Fi

If you've worked through these steps and your mobile failover still isn't performing as expected, our network team can review your configuration remotely. Open a Ticket with details of your router model, mobile carrier, and the symptoms you're experiencing.

Still Having Issues?

Need more help? If the issue persists after trying these steps, please open a support ticket and our team will assist you.

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