H3C s3100 series Command Manual page 286

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.
Currently, only S3100-SI series Ethernet Switches support the VLAN-VPN tunnel feature.
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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