An SD-WAN Service provides a virtual overlay network that enables application-aware, policy- driven, and orchestrated connectivity between SD-WAN User Network Interfaces, and provides the logical con-struct of a L3 Virtual Private Routed Network for the Subscriber that conveys IP Packets between Sub-scriber sites.
An SD-WAN Service operates over one or more Underlay Connectivity Services. Since the SD-WAN service can use multiple disparate Underlay Connectivity Services, it can offer more differenti-ated service delivery capabilities than connectivity services based on a single transport facility.
An SD-WAN service is aware of, and forwards traffic based on, Application Flows. The Service agreement includes specification of Application Flows—IP Packets that match a set of criteria—and Policies that de-scribe rules and constraints on the forwarding of the Application Flows.
SD-WAN benefits can be manifested in the ability to adjust aspects of the service in near real time to meet business needs. This is done by the Subscriber by specifying desired behaviors at the level of familiar business concepts, such as applications and locations and by the Service Provider by monitoring the per-formance of the service and modifying how packets in each Application Flow are forwarded based on the assignment of policy and the real-time telemetry from the underlying network components.
This document defines Service Attributes that describe the externally visible behavior and operation of an SD-WAN Service as experienced by the Subscriber and that form the basis of the agreement between the buyer of the service (the SD-WAN Subscriber) and the seller (the SD-WAN Service Provider). It describes the behavior from the viewpoint of the Subscriber Network and therefore all requirements are on the Service Provider.