Q: 1
How much must the MTU be increased when configuring the 802.1q VLAN tag?
Options
Discussion
Option B, Similar question popped up on practice exams, always 4 bytes for 802.1q tag.
B . It's 4 bytes for the 802.1q VLAN tag, official Cisco docs and lab sims always show that value. If you want to see it hands-on, try packet captures in a lab environment. Correct me if I'm missing something.
Maybe A. I remember some L2 headers are just a couple bytes, so 2 seemed right for VLAN tags. Not totally sure since there's some confusion between different tagging methods here, but that's how I used to think about it. Anyone see actual exam phrasing favoring this?
B vs D. Saw similar wording on another mock, and it's easy to mix up with QinQ/double tagging (which would be higher). Here, since it's just single 802.1q tag, I'm pretty sure they're after B, not D, but happy to hear arguments for D if anyone thinks otherwise.
Option B makes sense because the standard 802.1q tag adds exactly 4 bytes to the frame. I think sometimes people confuse it with other tagging mechanisms or scenarios like QinQ, but for single VLAN tagging it's just 4. If they've worded it to imply classic 802.1q, B is right. Anyone feel differently?
Wouldn’t the answer change if jumbo frames were already in use or if double tagging (QinQ) was specified? Standard is B for 802.1q, but extra tags or non-standard MTUs could flip it. Anyone else notice that edge case?
A is wrong, B, . Official Cisco guide or hands-on labs both cover this type of MTU question pretty well.
B tbh, single 802.1q tag is 4 bytes, D's a distractor if you're thinking QinQ.
Nah, not D-easy trap since double-tag (QinQ) would need more. For normal 802.1q it's B.
Would official Cisco docs or lab sims be best to check this MTU detail for 802.1q tags?
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