UniFi 5G and LTE Backup Best Practices

UniFi’s U5G Max family, LTE Backup, and LTE Backup Pro are designed to provide reliable cellular internet and failover connectivity for UniFi networks. This article outlines best practices for deploying cellular WAN and backup internet, including WAN modes, traffic control, and data usage management to ensure business continuity during primary WAN outages.

WAN Modes

UniFi 5G and LTE devices support two different WAN modes, depending on how you want to use cellular connectivity in your network: as a primary WAN or as a LAN-connected backup.

LAN-Connected Backup Internet

This is the preferred method for users who want a simple, plug-and-play failover setup or want to optimize 5G/LTE placement for signal strength without worrying about cabling back to the gateway. Unlike traditional backup links that require a WAN port, this method uses a GRE tunnel over the LAN to route traffic through the backup connection—giving you more flexibility in where the device is placed.

To set up Backup Internet mode:

1. Connect the cellular device to any PoE-enabled LAN port or switch.
2. Click Adopt in the UniFi Network application.
3. By default, backup Internet will be available to all networks (VLANs). 
4. (Optional) To limit or customize which VLANs use cellular backup, go to Settings > Networks > select a Network > disable UniFi Cellular Internet Backup.

Primary WAN (5G Max Only)

This mode is available exclusively on the UniFi 5G Max lineup, and treats the cellular connection as a standard WAN interface. This is ideal for deployments that need:

• A primary internet source over 5G 
• Load balancing or failover between multiple WAN links 
• Policy-based routing rules for more granular traffic management
• 5G tunnel connectivity in their Site Magic SD-WAN

To set up Standard WAN mode:

1. Plug your 5G device into the WAN1 or WAN2 port on your UniFi gateway. 
2. Power the device using a PoE adapter. 
3. Click Adopt in the UniFi Network application.
4. For advanced WAN configuration, see WAN Failover and Load Balancing. 

Managing Data Limits

To prevent unexpected costs, set a data limit for your LTE Backup:

1. Navigate to UniFi Devices and click on the LTE Backup to open its device panel.
2. Click on Settings.
3. Adjust settings to manage limits:
   • Set a Data Limit: Set a maximum usage cap to ensure costly overages do not occur.
     • Note: U-LTE automatically purchases additional data unless a limit is set, so defining a cap is essential for cost control.
   • Set an LTE Data Warning: Configure data thresholds to alert administrators when usage is approaching the plan’s limit.