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350-401 Practice Question: Which two statements about native VLANs on an…
Which two statements about native VLANs on an 802.1Q trunk are true? (Choose two.)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Frames belonging to the native VLAN are transmitted untagged on the trunk link.
The native VLAN is a key concept in 802.1Q trunking. Frames on the native VLAN are sent untagged to maintain compatibility with legacy devices that do not understand VLAN tags. Both ends of the trunk must agree on the native VLAN; a mismatch can cause connectivity issues or VLAN hopping. The default native VLAN is VLAN 1.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Frames belonging to the native VLAN are transmitted untagged on the trunk link.
Why this is correct
802.1Q does not tag frames for the native VLAN, so they are sent as standard Ethernet frames.
- ✓
The native VLAN must be the same on both ends of the trunk link.
Why this is correct
If the native VLANs differ, the switches will incorrectly place untagged frames into different VLANs, causing Layer 2 loops or connectivity issues.
- ✗
The native VLAN can be any VLAN from 1 to 4094.
Why it's wrong here
While many switches allow configuring any VLAN as native, VLANs 1002-1005 are reserved for legacy Token Ring and FDDI and cannot be used as native VLANs.
- ✗
The native VLAN is always VLAN 1 and cannot be changed.
Why it's wrong here
The native VLAN can be changed using the 'switchport trunk native vlan' command; it is not fixed to VLAN 1.
- ✗
A native VLAN mismatch will cause all traffic on the trunk to be dropped.
Why it's wrong here
A native VLAN mismatch does not drop all traffic; it causes the switches to place untagged frames into different VLANs, which can lead to connectivity issues but not a complete drop.
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Same concept, more angles
1 more way this is tested on 350-401
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which two statements about VLAN trunking using IEEE 802.1Q are true? (Choose two.)
medium- ✓ A.The 802.1Q tag includes a 12-bit VLAN ID field.
- ✓ B.The native VLAN is not tagged on an 802.1Q trunk.
- C.The native VLAN must always be VLAN 1.
- D.The 802.1Q tag uses a TPID value of 0x88A8.
- E.802.1Q supports a maximum of 4096 VLANs.
Why A: Correct: A is true because 802.1Q inserts a 4-byte tag after the source MAC address, which includes a 12-bit VLAN ID (0-4095). B is true because the native VLAN is not tagged; frames on the native VLAN are sent untagged to maintain backward compatibility with devices that do not understand trunking. C is incorrect because the native VLAN can be any VLAN, not just VLAN 1; it defaults to VLAN 1 but can be changed. D is incorrect because the 802.1Q tag uses a TPID of 0x8100, not 0x88A8 (which is used for Q-in-Q). E is incorrect because 802.1Q supports up to 4094 usable VLANs (1-1001 and 1006-4094), not 4096.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.