Reference Guide

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).
FTOS Behavior: In FTOS 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 FTOS versions, Dell Networking systems are required at
the egress edge of the intermediate network because only FTOS could recognize the significance of the destination
MAC address and rewrite it to the original Bridge Group Address. In FTOS version 8.2.1.0 and later, the L2PT MAC
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