VLAN Identification using IEEE 802.1q Tag

The 802.1q header is 4 Bytes
When the tag is created the FCS must be recalculated
When sent to end devices, this tag must be removed and the FCS recalculated back to its original number

802.1Q VLAN Tag Field	Function
Type	2-Byte field with hexadecimal 0x8100 This is referred to as Tag Protocol ID (TPID)
User Priority	3-bit value that supports
Canonical Format Identifier (CFI)	1-bit value that can support token ring frames on Ethernet
VLAN ID (VID)	12-bit VLAN identifier that can support up to 4096 VLANs