In Huawei's SD-WAN solution, when the CPE is located on the private network behind the NAT device, especially when the CPEs of two sites are located on the private network behind the NAT device at…

In Huawei's SD-WAN solution, when the CPE is located on the private network behind the NAT device, especially when the CPEs of two sites are located on the private network behind the NAT device at the same time, NAT traversal technology needs to be used between the CPEs. Which of the following technologies is used in Huawei's SD-WAN solution to help achieve NAT traversal between CPEs?