Which option lists the 802.1Q minimum frame size as 1522 bytes?

• A. 1518 bytes
• B. 1492 bytes
• C. 1522 bytes
• D. 1500 bytes

Answer: (C)

802.1Q tagging inserts a 4-byte tag into Ethernet frames, which increases the total frame length on VLAN trunks. An untagged Ethernet frame can be up to 1518 bytes, so with the tag added the maximum size becomes 1518 + 4 = 1522 bytes. That’s why 1522 bytes is the figure commonly associated with VLAN-tagged frames. The other values reflect either the untagged maximum (1518), the typical payload MTU (1500), or other encapsulation contexts (1492), but they do not represent the maximum size of a VLAN-tagged frame. Note that the actual minimum size for a tagged frame is smaller (68 bytes), but the question is addressing the size related to 802.1Q tagging, which is 1522 bytes.