Please see the networking pic at attachment.
The gateway of ZTE-AP locates at ZTE-AC .ZTE-AC-1 is the master AC.ZTE-AC-2 is the standby AC. Huawei S9312 interconnects ZTE-AP and ZTE-AC. S9312 transmits VLAN 512 from ZTE-AP to ZTE-AC transparently. The interface XG2/0/1 is at 12*10GE board of S9312.
In S9312-A,when the interface linking with ZTE-AC and the interface linking with another S9312 locate at the same board, if the ZTE master and standby AC switchover,the service is normal.Otherwise,when the two interfaces locate at different boards, the packets will be lost when master and standby AC switchover.