What does sd-wan inherit from SDN?

       First of all, the SD - WAN is in the field of WAN extension of SDN thought. In addition to the research object of network (SDN geared to the needs of the local LAN, SD, WAN WAN), the "turn accused of separation" is the basic idea of inheritance. In addition, there are similarities in terms of hardware universalization, network virtualization, control centralization, and data transparency.

　　But as a result of the application of SD - WAN and SDN environment and business environment is different, the form and the realizing method of the two considerations are quite different:

　　In the forwarding plane control different requirements:

　　SDN emphasizes forward entirely by three layers of hardware implementation, in the premise of port forwarding line speed, namely to be able to forward control depth elaboration as far as possible. SD - WAN demands forward is for the transport layer (Underlay) abstract encapsulation proposed requirements, that is to say, through the SD - WAN established end-to-end logical link (physical or virtual) and network (overlay) should be able to be invoked in the form of abstract transport resources, overlay transmission work should not be involved in the Underlay complex transmission protocol processing. So it can simplify the management of communication and configuration.

　　In the control plane forward different control objectives:

　　SDN control goal is to ensure that all domain (LAN) within the business flow of standard forwarding performance (bandwidth). SD - the control target of WAN is to ensure that all domain (WAN WAN) within the scope of the reliability of the internal business flow (QoS) and performance (bandwidth), therefore need to be able to handle a variety of SD - WAN transmission network (MPLS/SDH, Ethernet, wireless, 4 g/LTE, satellite communications, etc.), and in the range of domain forwarding service scheduling these networks for the business flow.