Fortigate Dual Hub Using sdwan and Fortimanager

[Daniyal007]

Hello everyone,

We are planed to configured Dual hub topology in our company, 

However we have currently deployed Single hub design in which we have 11 spokes and 1 hub.

Our plan is to make 1 spoke site as secondary hub.

MY QUESTION IS , that we already deployed single hub design and now moving to dual hub using Fortimanager , if i click on dual hub template from Fortimanager does it remove my current single hub configuration and recreate it using scratch ? or we have to only add secondary hub by using dual hub template in the Fortimanager. (We did not created Single Hub Design using Fortimanager)

 Kindly help i am just stuck on this.

[Stephen_G]

Hello,

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible.

If anyone seeing this has any ideas, please feel free to contribute!

Thanks,

[Stephen_G]

Hi,

We're still trying to get you an answer or help. Anyone with any info, please feel free to reply!

[akileshc]

Dear Daniyal,

When using FortiManager SD-WAN overlay templates, the configuration is template-driven, meaning FortiManager generates and pushes the overlay setup (including tunnels, BGP, and related interfaces) to the participating devices.

Since your current single-hub SD-WAN design was manually configured (not created via FortiManager), applying a dual-hub overlay template directly will not “merge” with or adapt to your existing configuration — instead, it will recreate the overlay design from scratch based on the template parameters. This can overwrite existing VPN and overlay-related settings on the FortiGate.

To avoid configuration loss, you have two possible approaches:

1. Import and synchronize first:

   • Import your existing FortiGates (hub and spokes) into FortiManager.

   • Use Retrieve Config and Reconcile to align FortiManager’s database with the current device configuration.

   • Attempt to import the existing SD-WAN configuration into an SD-WAN template.

   • Once this is done, you can explore converting or expanding it into a dual-hub overlay setup.

2. Rebuild using the dual-hub template:

   • Plan your overlay IP and loopback address ranges (as per template prerequisites and network planning).

   • Define your BGP AS number and underlay interfaces.

   • Recreate the SD-WAN overlay from scratch using the Dual Hub topology in FortiManager.

   • Once complete, deploy it to all participating devices.

It’s recommended to first import and validate your current setup in FortiManager before transitioning to a dual-hub design.

For details, please refer to:

• Template prerequisites and network planning

• SD-WAN overlay template IP network design