Some question about SDWAN?

Hi All.

I'm currently reviewing SDWAN and I have question regarding how the technology works & design especially on Underlay and Overlay.

Question:

a. We have a centralize monitoring server and remote server which is connected to MPLS (traditional way).

• Does all remote and monitoring of vedge/controller should be on its VPN 512?
• Since from traditionally we just announce the mgmt to MPLS network or if internet router we build a secure connection to HUB or headend device or directly accessing the RTR using it WAN public IP.

b. How interconnection/communication between the traditional infrastructure and sdwan infra.

c. Common design in data center for underlay and overlay. How default routing being implemented.

d. If Multiple default route being use, does it means it being load balance? If Yes, How can we verify the actual exit interface of the traffix (ex. in traditional we have show ip cef) ?

e. If we need to forward Customer Internet traffic directly to internet of the site. We can achieve this by route leaking right ? If yes, another question is that .. If we have multiple default route on transport vpn how can we ensure that all data traffic will be forwarded only to internet circuit not on MPLS?

Let me know your inputs. Thank you so much.