When a Huawei switch is connected to another vendor' device, the two devices may fail to communicate because of different keys in BPDUs even though they have the same domain name, revision level, and VLAN mapping table. To solve this problem, run the stp config-digest-snoop command to enable digest snooping. This function enables the Huawei switch to keep its BPDU key consistent with that used on the peer device.