If configured, the VLAN tag is added to the stripped packet of both tagged and non-tagged packets in the first L2 header. The following figure shows tag addition for a non-tagged packet.
For a tagged frame, tag-addition is based on the existing tag. The operation is applied to the E Tag, VN Tag, or C Tag, as shown in the following figure. Note the newly added C Tag.
STag and double-CTag additions are no-operation (NOOP) additions, meaning it's a computer processor instruction. The following figure shows an example of tag addition for NOOP cases.
