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understanding multi-wan network backup

Multi-WAN Network Backup is a high-availability feature on RAK gateways that maintains stable internet connectivity. It monitors multiple WAN interfaces such as Ethernet, Wi-Fi, and cellular, and automatically switches to a backup connection if the primary link fails. When the main connection is restored, the system automatically switches back, ensuring continuous network uptime without manual intervention.

How It Works

Multi-WAN Network Backup operates using a priority and tracking mechanism that monitors all configured WAN interfaces.

Interface Priority

Each WAN interface can be assigned a priority level (for example, Ethernet > Wi-Fi > Cellular). The gateway always uses the highest-priority interface that is currently available.

Availability Tracking

Interface status is verified through periodic health checks using one of two tracking methods:

  • Ping Tracking: Sends ICMP requests to a target IP (e.g., 8.8.8.8)

  • HTTP Tracking: Sends HTTP/HTTPS GET requests to a target URL (e.g., http://example.com/ping)

If an interface fails several consecutive checks (based on configured thresholds), it is considered down.
Once it passes enough successful checks, it is marked up again.

Failover and Recovery Logic

  • If the active interface is marked down, the system will automatically switch to the next available interface based on priority.

  • If the original (higher-priority) interface becomes healthy again, the gateway will switch back to it automatically.

Configuration

Set Interface Priority

  1. Go to the Network section in the web UI.

  1. Click Change Priority.

  1. Use the arrows () next to each interface name to change its priority.

  • The upward arrow increases the priority, making that network the preferred one.

  • The downward arrow decreases the priority, making it a secondary or backup network.

  1. Click Save to apply the settings.

Enable Tracking on Each Interface

Tracking ensures that the system knows whether an interface is actually working. Follow these steps for each interface:

  1. Go to the Network in the Web UI.

  2. Select the target interface and expand the interface by clicking the arrow on the right to expand its configuration settings.

  3. Go to the Settings > Tracking section.

  4. Configure the tracking parameters based on your chosen method (ICMP or HTTP):

  • Target address: Enter one or more IPs (for ICMP) or URLs (for HTTP). After typing an address, click the Add button to save it.

  • Reliability: The minimum number of target addresses that must respond in each cycle to consider the interface up.

  • Ping count: Number of pings sent in each check cycle (e.g., 1 ping per test).

  • Ping timeout: Maximum time (in seconds) to wait for each ping response.

  • Ping interval: How often the system performs a ping check (e.g., every 5 seconds).

  • Down: Number of consecutive failed checks needed to mark the interface as down.

  • Up: Number of consecutive successful checks needed to mark the interface as up again. 

  1. Click Save to apply the settings.

Once interface priority and tracking are configured, Multi-WAN network backup becomes active and ensures continuous connectivity.

Troubleshooting

Issue Possible Cause Solution
Interface not switching as expected
  1. Tracking not enabled
  2. Thresholds too conservative
  3. No available backup interface
  • Make sure tracking is enabled on all interfaces
  • Lower the Down threshold
  • Ensure at least one backup interface is enabled and reachable

FAQs

  1. How many WAN interfaces can be used at the same time?
    You can configure multiple WAN interfaces (Ethernet, Wi-Fi, Cellular). However, only one will be active at a time based on priority; the others serve as backups.

  2. Can I disable one of the WAN interfaces after setting priorities?
    Yes. If a WAN interface is not needed, disable it from Network > [Ethernet / Wi-Fi / Cellular] > Settings > General.

  3. Will the gateway automatically switch back to the higher-priority interface once it's restored?
    Yes. When tracking is enabled, the gateway continuously monitors all WAN interfaces. If the higher-priority connection becomes stable again, the system automatically switches back without requiring a reboot or manual action.

  4. What do the green and red indicators next to WAN interfaces mean?
    🟢 Green: Interface is active
    đź”´ Red: Interface is offline or unavailable

 

Changelog
  • Version 1 - Understanding Multi-WAN Network Backup
    • Date Published: 11/01/2025

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