How to configure Link Backup on Dual WAN Router using the new GUI

With the Load Balance function, TP-Link Routers can provide multi-WAN access, which can not only reduce the traffic burden and increases the egress bandwidth, but also automatically switch all the new sessions to another WANs when the dropped line is detected, thereby improving the network reliability.

Based on this, TP-Link Routers further provide the Link Backup function, allowing you to customize the usage of multi-WAN access with Timing or Failover modes. Simply put, only the primary WANs are used for data forwarding under normal circumstances, the Backup WANs are always on standby to start data forwarding as soon as the triggered condition is detected, such as the set time or link state change.

In summary, both functions can improve redundancy, but Load Balance will use all WANs, while Link Backup will use parts and backup other parts of WANs according to your configuration.

1. What is the Timing mode Link Backup and how to set it?

For example, a customer has a TL-R600VPN V4 and there are two WAN ports connected to the Internet. He wants to use WAN1 at work and use WAN2 after work. The working time is from Monday to Friday 8:00-18:00.

Timing mode Link Backup can help him to fulfill his needs.

Step 1. Set up the Time Range for the Backup WAN effective time.

Choose the menu Preferences -> Time Range, you can define the time range entry on this page.

Step 2. Enable Load Balancing

Choose the menu Transmission -> Load Balancing -> Basic Settings. Check Enable Load Balancing. Please note that “Enable Load Balancing” must be checked if you want to configure link backup. Otherwise link backup won’t work normally.

Step 3. Choose the Primary WAN and Backup WAN.

Choose the menu Transmission -> Load Balancing -> Link Backup. Set up Primary WAN as WAN1 and Backup WAN as WAN2.

When having two or more primary WANs, it makes differences between the two options Failover(Enable backup link when any primary WAN fails) and Failover(Enable backup link when all primary WAN fails). The former will take effect even though only a single WAN goes down, while the latter will work only when all primary WANs are down.

Please note that during the effective time, Backup WAN will be online and Primary WAN will be offline. At other times, Primary WAN will be online and Backup WAN will be offline.

Note: If the online WAN failed, the offline WAN will still keep offline.

2. What is the Failover mode Link Backup and how to set it?

For example, a customer has a TL-R600VPN V4 and there are two WAN ports connected to the Internet, where WAN1 is the fiber-optic access paid monthly and WAN2 is the LTE access paid according to the data flow. Therefore, he would like to mainly use WAN1 and only switch to WAN2 automatically when WAN1 is detected as offline.

Failover mode will help him to fulfill his needs. The network reliability will be increased and the costs will be reduced a lot.

Step 1. Enable Load Balancing.

Choose the menu Transmission -> Load Balancing -> Basic Settings. Check Enable Load Balancing. Please note that “Enable Load Balancing” must be checked if you want to configure link backup. Otherwise link backup won’t work normally.

Step 2. Choose the Primary WAN and Backup WAN.

Choose the menu Transmission -> Load Balancing -> Link Backup. Set up Primary WAN as WAN1 and Backup WAN as WAN2. Then WAN1 will be still online, and all the data flows will be forwarded via WAN1. As long as WAN1 is detected as offline, WAN2 will be online and all the sessions will be forwarded via WAN2.

Step 3. Setup Online Detection.

Choose the menu Transmission->Load Balancing->Online Detection.

Link Backup feature worked based on Online Detection. Auto mode means DNS lookup is used to detect the route to the gateway of the WAN port. If you want specific route detection, you can choose Manual mode to customize the destination IP of Ping and DNS lookup.

Both of the above examples use two WANs, actually, you can use all WANs as you want. As soon as you log in to the management page, you will know how to do it, so I won’t go into detail here.