Forti Manager SD-WAN overlay template concerns

[FortiSL1989]

Hi All,

We are trying to deploy a new SD-WAN setup with dual hub and spoke type deployment. We have below devices in place,

Hub devices -> 2 X 200F FortiGates

Spoke devices -> 10 X 60F FortiGates

FortiManager VM

I have gone through the SD-WAN overlay configuration setup and I have a few doubts regarding this,

1) As we are using the overlay template, the HUB BGP template inside the overlay template will have all the required BGP configurations for the HUB? If we are replacing a DC firewall setup that already has BGP peering with ISPs, do we need to configure all the BGP-related changes for the HUB device through this template?

2) Can we modify the template (such as BGP AS numbers, and remote AS numbers for DC from the branch template) since the DC HUB device already has a public AS number configured?

Thanks in advance. 

[jiahoong112]

This document demonstrates an example of FortiManager configuration for SDWAN ADVPN. ADVPN in Fortigate is basically a Hub-Spoke ipsec topology with the ability to create shortcut tunnels for Spoke-to-Spoke communication. If you're not interested in the dynamic shortcut tunnel creation, can simply disable the 'auto-discovery' setting in the ipsec phase1 settings. https://docs.fortinet.com/document/fortimanager/6.4.0/examples/380098/sd-wan-with-advpn-single-hub