References
RFC 4023, “Encapsulating MPLS in IP or Generic Routing Encapsulation (GRE),” https://tools.ietf.org/html/rfc4023, March 2005.
RFC 5389, “Session Traversal Utilities for NAT (STUN),” https://tools.ietf.org/html/rfc5389, October 2008.
“Cisco Catalyst SD-WAN,” https://www.cisco.com/site/us/en/solutions/networking/sdwan/index.html.
“SD-WAN Platforms,” https://www.cisco.com/c/en/us/solutions/collateral/enterprise-networks/sd-wan/nb-06-sd-wan-sol-overview-cte-en.html#SDWANplatforms.