mediumMultiple Choice
CCNP Practice Question: Consider this configuration: interface…
Consider this configuration:
interface Port-channel1 switchport mode trunk switchport trunk native vlan 999
!
interface GigabitEthernet0/1 switchport mode trunk switchport trunk native vlan 999 channel-group 1 mode active
!
interface GigabitEthernet0/2 switchport mode trunk switchport trunk native vlan 999 channel-group 1 mode active
What is the effect of the 'switchport trunk native vlan 999' command on the EtherChannel?
⚠ Common exam trap
Cisco often tests the misconception that the native VLAN must be VLAN 1 or that changing it will break the EtherChannel, but the key requirement is consistency across all interfaces, not a specific VLAN number.
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
✓
The EtherChannel will use VLAN 999 as the native VLAN, and any untagged frames will be associated with VLAN 999.
The 'switchport trunk native vlan 999' command on each physical interface and on the port-channel interface ensures that the EtherChannel uses VLAN 999 as the native VLAN. Untagged frames received on any member link are associated with VLAN 999, and frames tagged with VLAN 999 are sent untagged. Since the configuration is consistent across all interfaces, the EtherChannel forms correctly and operates with VLAN 999 as the native VLAN.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The EtherChannel will drop all untagged frames because the native VLAN is not in the allowed list.
Why it's wrong here
The native VLAN is the VLAN assigned to untagged frames on an 802.1Q trunk, and it does not need to be listed in the allowed VLAN list for those frames to be forwarded. The EtherChannel will not drop untagged frames merely because the native VLAN is absent from the allowed list; instead, untagged traffic is associated with the configured native VLAN. A mismatch between the allowed list and the native VLAN would only affect tagged traffic in that VLAN, not untagged frames.
- ✓
The EtherChannel will use VLAN 999 as the native VLAN, and any untagged frames will be associated with VLAN 999.
Why this is correct
Correct: When the native VLAN is configured as 999 on the EtherChannel, the port-channel treats all untagged frames as belonging to VLAN 999. This is standard 802.1Q trunk behavior: untagged frames are placed into the native VLAN, and in this case the native VLAN is explicitly set to 999 rather than the default VLAN 1. Both ends of the EtherChannel must agree on the native VLAN value to avoid misconfiguration, and here that consistency is maintained.
- ✗
The EtherChannel will not form because the native VLAN must be the same across all interfaces, which it is.
Why it's wrong here
The statement is incorrect because the native VLAN on all interfaces is already consistent (VLAN 999), which satisfies the requirement for forming an EtherChannel. The native VLAN does need to match across all member links, but since it does match, the EtherChannel will form normally. Merely having a consistent native VLAN is a prerequisite, not a barrier, so the claim that the channel will not form is false.
- ✗
The EtherChannel will form but the native VLAN will be ignored on the port-channel.
Why it's wrong here
The port-channel does not ignore the native VLAN; instead, it inherits the native VLAN configuration from the physical member interfaces when the logical interface is created. Once the EtherChannel is operational, the port-channel uses VLAN 999 as its native VLAN, so any untagged frames arriving on the port-channel are associated with that VLAN. The native VLAN is fully functional on the port-channel and must be the same on both sides of the channel to prevent traffic misclassification.
Visual reference
About these practice questions
Courseiva writes every 350-401 question from scratch — 1,923 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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.