Enterasys VH-2402-L3 Management Manual page 139

802.1Q standard. Because the VID is 12 bits long, 4094
unique VLANs can be identified.
The tag is inserted into the packet header making the entire
packet longer by 4 octets. All of the information contained in
the packet originally is retained.
Figure 2-6. 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.
9033691-01 VH-2402-L3 Management Guide 131