Command Manual – MSTPH3C S3100-52P Ethernet Switches Chapter 2 BPDU Tunnel Configuration Commands2-1Chapter 2 BPDU Tunnel Configuration Commands2.1 BPDU Tunnel Configuration Commands2.1.1 vlan-vpn tunnelSyntaxvlan-vpn tunnelundo vlan-vpn tunnelViewSystem viewParameterNoneDescriptionUse the vlan-vpn tunnel command to enable the BPDU Tunnel function for a switch.Use the undo vlan-vpn tunnel command to disable the BPDU Tunnel function.The BPDU Tunnel function enables BPDUs to be transparently transmitted betweengeographically dispersed user networks through specified VLAN VPNs in operator’snetworks, through which spanning trees can be calculated across these user networksand are independent of those of the operator’s network.By default, the BPDU Tunnel function is disabled.Note:z The BPDU Tunnel function can only be enabled on STP-enabled devices.z The BPDU Tunnel function can be enabled only on access ports.z To enable the BPDU Tunnel function, make sure the links between operator’snetworks are trunk links.z As the VLAN-VPN function is unavailable on ports with 802.1x, GVRP, GMRP, STP,or NTDP enabled, the BPDU Tunnel function is not applicable to these ports.Example# Enable the BPDU Tunnel function for the switch.