Hot Standby link an enhanced backup link, for the WAN links of an Edge, with pre-established VCMP tunnels. When the active links are down, Hot Standby link enables immediate switchover by using the pre-established VCMP tunnels.
To configure a Hot Standby link on an Edge, ensure that the Edge is upgraded to software image version 4.0.0 or later.
- In the SD-WAN Orchestrator portal, click .
- In the Edges page, either click the device Icon next to an Edge or click the link to the Edge and click the Device tab.
- Scroll down to WAN Settings.
- For an existing auto-detected or user-defined WAN Overlay, click Edit to modify the settings.
- To create a new Public or Private overlay, click Add User Defined WAN Overlay.
- In the User Defined WAN Overlay window, choose the Link Type.
- Click Advanced to configure Hot Standby links.
Select Hot Standby from the Link Mode drop-down.Note: You cannot enable Hot standby link for a Hub.Select the Minimum Active Links from the drop-down. This option indicates the number of active links that can be present in the network at a time. When the number of current active links that are UP goes below the selected number, then the Hot Standby link comes up. The range is 1 to 3, with the default being 1.
- Configure other options as required and click Update Link to save the settings.
Note: For more information on other options in the WAN Overlay window, see Configure Edge WAN Overlay Settings.
Once you configure the Hot Standby link, the tunnels are setup, which enables a quick switchover in case of a failure. The Hot Standby link receives no data traffic except the heartbeats, which are sent every 5 seconds.
When the path from Edge to Primary Gateway on Active links goes down and when the number of Active links that are UP is below the number of Minimum Active Links configured, the Hot Standby link will come up. The traffic is sent through the Hot Standby path.
When the path to Primary Gateway comes up on Active links and the number of Active links exceeds the number of Minimum Active Links configured, the Hot Standby link goes to the STANDBY mode. The traffic flow switches over to the Active links.
What to do next
You can monitor the Hot Standby links in the monitoring dashboard. See Monitor Hot Standby Links.