Dell S4820T Configuration Manual page 871

Figure 116. VLAN Stacking without L2PT
You might need to transport control traffic transparently through the intermediate network to the other
region. Layer 2 protocol tunneling enables BPDUs to traverse the intermediate network by identifying
frames with the Bridge Group Address, rewriting the destination MAC to a user-configured non-reserved
address, and forwarding the frames. Because the frames now use a unique MAC address, BPDUs are
treated as normal data frames by the switches in the intermediate network core. On egress edge of the
intermediate network, the MAC address rewritten to the original MAC address and forwarded to the
opposing network region (shown in the following illustration).
Dell Networking OS Behavior: In Dell Networking OS versions prior to 8.2.1.0, the MAC address that Dell
Networking systems use to overwrite the Bridge Group Address on ingress was non-configurable. The
value of the L2PT MAC address was the Dell Networking-unique MAC address, 01-01-e8-00-00-00. As
such, with these Dell Networking OS versions, Dell Networking systems are required at the egress edge of
871
Service Provider Bridging