User need to use USG firewall to replace its former firewall. Do the MAC bonding on the up link device of the former network. If the USG firewall can’t go on the change of the out interface MAC bonding, will result in the network can not achieve interoperability.
By creating virtual interface to realize the change of MAC, as follows：
1、create eth-trunk interface；
2、change eth-trunk interface MAC as old device MAC;
3、Let practical connective physical interface access to eth-trunk interface.
The MAC of USG firewall is write in physical interface，that is to say the MAC of physical interface can not be changed by configuration.