LPIC-2 Advanced Networking Configuration Practice Question
Which TWO statements about VLAN tagging are correct?
⚠ Common exam trap
It's easy for candidates to assume VLAN tags are always 12 bits, confusing the VLAN ID field with the entire tag, or they think only switches can add tags, missing the fact that hosts (e.g., Linux with 802.1Q interfaces) can also tag frames.
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
✓
Untagged frames on a trunk port are typically assigned to the native VLAN
On a trunk port, frames that do not carry a VLAN tag are considered to belong to the native VLAN. The switch forwards these untagged frames as part of the native VLAN, which is typically VLAN 1 by default but can be configured to any VLAN. This behavior is defined in IEEE 802.1Q and is essential for interoperability with devices that do not support VLAN tagging.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
VLAN tagging can only be used with Ethernet
Why it's wrong here
VLAN tagging can also be used with other technologies like Fiber Channel over Ethernet (FCoE).
- ✗
VLAN tags are always 12 bits
Why it's wrong here
The tag has 4 bytes: TPID (2 bytes), TCI (2 bytes) which includes 3-bit priority, 1-bit CFI, 12-bit VLAN ID.
- ✓
Untagged frames on a trunk port are typically assigned to the native VLAN
Why this is correct
Standard behavior: untagged traffic on a trunk belongs to native VLAN.
- ✗
VLAN tags are added by the switch, not the host
Why it's wrong here
Hosts can also add VLAN tags if configured as VLAN interfaces.
- ✓
Linux can use VLAN interfaces with 802.1q tags
Why this is correct
Linux supports VLAN interfaces via ip link or vconfig.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.