H3C s3600 series Command Manual page 281

By default, the VLAN-VPN tunnel function is disabled.
The VLAN-VPN tunnel function can only be enabled on STP-enabled devices.
To enable the VLAN-VPN tunnel function, make sure the links between operator's networks are
trunk links.
If a fabric port exists on a switch, you cannot enable the VLAN-VPN function for any port of the
switch.
Examples
# Enable the VLAN-VPN tunnel function for the switch.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] vlan-vpn tunnel
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