SD-WAN uses certificates to authenticate each other to the Root CA (VBond) to the other controllers including vEdge, ostensibly using the same design of a PKI.
The controllers authenticate the certificate fields which include the Organization name, this field along forms a union with the other controllers and devices.
https://www.cisco.com/c/en/us/td/docs/solutions/CVD/SDWAN/cisco-sdwan-controller-cert- deploy-guide.html