The VLAN Tag increases the frame header by __________ bytes?

Question

Options

• A0
• B16
• C2
• D8
• E4

• C
  3% (1)
• D
  3% (1)
• E
  93% (28)

Explanation

VLAN Tag Frame Header Increase

A VLAN tag, defined by the IEEE 802.1Q standard, inserts a 4-byte (32-bit) tag into the Ethernet frame header between the source MAC address and the EtherType field. Those 4 bytes consist of 2 bytes for the Tag Protocol Identifier (TPID, set to 0x8100) and 2 bytes for the Tag Control Information (TCI), which carries the 12-bit VLAN ID, 3-bit priority (PCP), and 1-bit DEI flag.

Why the distractors are wrong:

• A (0): Zero bytes would mean no tag is added - that describes an untagged frame.
• B (16): 16 bytes is the size of a full IPv6 address; it has no relation to 802.1Q tagging.
• C (2): Only half the tag - 2 bytes covers just the TPID or the TCI, not the complete tag.
• D (8): 8 bytes is a common value in other contexts (e.g., 802.1ad double-tagging adds 8 bytes total), but a single 802.1Q tag is only 4.

Memory tip: Think "VLAN = 4 bytes" by remembering the tag splits evenly - 2 bytes TPID + 2 bytes TCI = 4. The number 4 also matches the 4-letter word "VLAN."

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