BPDU Tunneling
The bridge protocol data unit (BPDU) tunneling technology allows a user's networks located in different areas to transparently transmit BPDUs on a specified VLAN VPN within an operator's network. In this manner, all devices on the user's networks can calculate the spanning tree. The user's networks and the operator's networks have their own independent spanning trees.
As shown in Figure 1, the upper part is an operator's network; the lower part is a user's network. The operator's networks hold ingress/egress devices; the user's networks consist of user's network A and user's network B.
You can configure the packet ingress device to replace the original destination MAC address of a BPDU with a MAC address in a special format and the packet egress device to replace the MAC address in a special format with the original MAC address. In this manner, the BPDU is transparently transmitted.
