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Treatment of tagged and untagged frames

An 8000 Series switch associates a frame with a VLAN based on the data content of the frame and the configuration of the destination port. Whether the frame is tagged or untagged dictates how that frame is treated.

If a tagged frame is received on a tagged port, with a VLAN ID specified in the tag, the 8000 Series switch directs it to that VLAN, if it is present. For tagged frames received on an untagged port, you can configure that port to either discard the frame or accept it. If you choose not to discard tagged frames, the 8000 Series switch sends the frame to the VLAN identified in the frame's tag.

For untagged frames, VLAN membership is implied from the content of the frame itself. For untagged frames received on a tagged port, you can configure the port to either discard or accept the frame. If you configure a tagged port to accept untagged frames, the port must be assigned to a port-based VLAN in spanning tree group 1 (STG1).

How the frame is forwarded is based on the VLAN on which the frame is received and on the forwarding options available for that VLAN. Passport 8000 Series switches try to associate untagged frames with a VLAN in the following order:

If the frame meets none of the criteria listed above, it is discarded.

See also:


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