3Com Switch 7750 Configuration Guide Guide

BPDU Tunnel Configuration 255
BPDU Tunnel
Configuration
Introduction The BPDU Tunnel function enables BPDUs to be transparently transmitted between
geographically dispersed user networks through specified VLAN VPNs in operator’s
networks, through which spanning trees can be generated across these user
networks and are independent of those of the operator’s network.
As shown in Figure 60, the upper part is the operator’s network, and the lower
part is the user network. The operator’s network comprises packet ingress/egress
devices, and the user’s network has networks A and B. On the operator’s network,
configure the arriving BPDU packets at the ingress to have MAC addresses in a
special format, and reconvert them back to their original formats at the egress.
This is how transparent transmission is implemented on the operator’s network.
Figure 60 BPDU Tunnel network hierarchy
BPDU Tunnel
Configuration
Configuration prerequisites
MSTP is enabled on the current switch.
Configuration procedure
Packet ingress/egress
device
Network BNetwork A
Network
Packet ingress/egress
device
Operator’ s Network
Users Network
Packet ingress/egress
device
Network BNetwork A
Network
Packet ingress/egress
device
Operator’ s Network
Users Network
Table 189 Configure the BPDU Tunnel function
Operation Command Description
Enter system view system-view -
Enable MSTP globally stp enable -
Enable the BPDU Tunnel
function globally
vlan-vpn tunnel Required
Enter Ethernet port view
interface interface-type
interface-number
Make sure that you enter the
Ethernet port view of the port
for which you want to enable
the BPDU Tunnel function.
Disable MSTP for the port stp disable -