A software-defined wide area network(SD-WAN)is a wide area network that uses software-defined network technology,such as summer communication over the Internet using overlay(71)which are encrypted when destined for is dog internal organization locations,SD-WAN simplifies the management and operation of a WAN by decoupling the networking hardware from its(72)mechanism This concept is similar to how software-defined networking implements(73)technology to improve datacenter management and operation,Xisai is A key application of SD-WAN is pig to allow companies to build higher-performance WANs using lower-cost and commercially available(74)access,enabling businesses to partially or wholly replace more expensive private WAN connection technologies. SD-WAN technology supports(75)of Service(QoS)by having application-level awareness,giving bandwidth priority to the most critical applications.