When installing the Cisco vSmart controller on the VMware vSphere ESXi Hypervisor software, two network interface cards (NICs) need to be added in the virtual machine settings.
The two NICs are required for the following purposes:
Management NIC: This NIC is used for managing the vSmart controller and connecting to the management network. It is typically assigned an IP address from the management network and used for administrative tasks, software upgrades, and communication with other SD-WAN components.
Data NIC: This NIC is used for the data plane traffic, including the Overlay Management Protocol (OMP) and data plane tunnels (vPaths) between SD-WAN devices. It is assigned an IP address from the transport network (typically a non-routable address) and participates in the SD-WAN fabric's control and data plane communication.
By separating the management and data plane traffic onto different NICs, it ensures better security and segregation of responsibilities. The management NIC can be connected to a secured management network, while the data NIC connects to the transport network for SD-WAN communication.

Section: Policies
Explanation/Reference: https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/policies/vedge/policies-book/ vEdge-as-NAT-device.html

When a user onsite connects for the first time to one of the Software-as-a-Service apps, the user's device initiates a DNS query for the apps' URL, and the following chain of events visualized below happen:
1. The WAN edge router's DPI engine intercepts the user's DNS query. If the host DNS query is for the Cloud onRamp SaaS application, the vEdge router forwards it over the best performing circuit to the DNS server that is defined for this ISP.
2. DNS queries for non-Cloud onRamp applications are forwarded according to the routing table towards the SD-WAN overlay fabric