I have a question regarding the underlay networking of Cisco SD-WAN.
Ex - I am using MPLS or Internet link as my underlay. OSPF is my service side routing protocol used for my DC & branch routing.
To establish IPSec tunnel over the underlay either with MPLS link or Internet link is it required to use BGP in case of Cisco SD-WAN ?
Is BGP required to have the underlay communicate with each other for establishing the IPSec communication ?