D-Link DES-3326 User Manual page 77

24-port NWay Ethernet Switch User's Guide
Figure 5-8. IEEE 802.1Q Tag
The EtherType and VLAN ID are inserted after the MAC source
address, but before the originial EtherType/Length or Logical
Link Control. Because the packet is now a bit longer than it was
originally, the Cyclic Redundancy Check (CRC) must be
recalculated.
Switch Management and Operating Concepts
61