Dell Force10 C150 Configuration Manual page 960

You can configure the first eight bits of the TPID using the command
The TPID on the C-Series and S-Series systems 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, then 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 in
Figure 46-11. For the same traffic types, if you configure TPID 0x8100, then 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 in
Therefore, a mismatched TPID results in the port not differentiating between tagged and untagged traffic.
Figure 46-9. Single and Double-tag TPID Match on the C-Series and S-Series
Building C
TPID PCP
(0x8100)
960 | Service Provider Bridging
TPID 0x8100
R2-C-Series
TPID: 0x8100
R1-C-Series
TPID: 0x8100
R4-Non-Force10 System
TPID: 0x8100
CFI VID
(0) (VLAN Red)
Figure 46-11.
Building D
R3-C-Series
TPID: 0x8100
PCP
TPID CFI
(0x8100) (0)
Building A
vlan-stack protocol-type
Building B
PCP
VID TPID CFI VID
(VLAN Purple) (0x8100) (0) (VLAN Red)
.