What is the 802.1Q minimum frame size listed?

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

Answer: (A)

802.1Q tagging inserts a 4-byte VLAN tag into the Ethernet frame. That tag sits after the source MAC and before the EtherType, increasing the total frame size by 4 bytes. The standard untagged Ethernet frame maxes out at 1518 bytes (6 bytes dest, 6 bytes src, 2 bytes EtherType/Length, up to 1500 bytes payload, and 4-byte CRC). Add the 4-byte VLAN tag, and the maximum size for a VLAN-tagged frame becomes 1522 bytes. In practice, references that list 802.1Q frame sizes use 1522 bytes for tagged frames, which is why the correct choice is 1522. The other options reflect untagged sizes or different MTU contexts and do not represent the tagged-frame size.