were treated as the same TPID, as shown in the following illustration. Dell Networking OS Versions 8.2.1.0
and later differentiate between 0x9100 and 0x91XY, also shown in the following illustration.
You can configure the first 8 bits of the TPID using the vlan-stack protocol-type command.
The TPID is global. Ingress frames that do not match the system TPID are treated as untagged. This rule
applies for both the outer tag TPID of a double-tagged frame and the TPID of a single-tagged frame.
For example, if you configure TPID 0x9100, the system treats 0x8100 and untagged traffic the same and
maps both types to the default VLAN, as shown by the frame originating from Building C. For the same
traffic types, if you configure TPID 0x8100, the system is able to differentiate between 0x8100 and
untagged traffic and maps each to the appropriate VLAN, as shown by the packet originating from
Building A.
Therefore, a mismatched TPID results in the port not differentiating between tagged and untagged traffic.
Service Provider Bridging
845