The basic forwarding paradigm for an SD-WAN Service is a Virtual Private Routed Network (VPRN) as described in RFC 2764 . As a VPRN, the SD-WAN Service relies on destination-based IP forwarding (usually based on standard IP longest prefix match), which can then have additional forwarding constraints as a result of Policies applied by the SD-WAN Service such as:
Source IP address
Layer 4-based criteria such as TCP port number
Layer 7 Application Flows
The Subscriber and the Service Provider may use static routing or a dynamic routing protocol at the UNI to exchange information about reachable IP Prefixes. Details of this are out of scope for this version of the specification.
[R3] The Service Provider MUST NOT deliver an ingress IP Packet to a UNI where the destination address is not reachable, based on longest prefix matching.
SD-WAN Services forward unicast, multicast, and broadcast IP Packets; however, this specification includes requirements for forwarding unicast IP Packets. Requirements for forwarding of multicast and broadcast IP Packets are out of scope for this version of the standard.