CCNA Switching and Network Access Practice Question
A network administrator is configuring a Cisco IOS switch port that connects to an IP phone and a PC daisy-chained behind the phone. The administrator wants the PC's data traffic to be untagged on VLAN 20, and the phone's voice traffic to be tagged with VLAN 30. The phone is already configured to use VLAN 30 for voice. Which configuration on the switch port will accomplish this?
⚠ Common exam trap
Many candidates confuse the voice VLAN and data VLAN assignments, or incorrectly using a trunk port when an access port with voice VLAN is sufficient.
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
✓
switchport mode access switchport access vlan 20 switchport voice vlan 30
The correct configuration uses an access port for data VLAN 20 and a voice VLAN 30. This allows the PC to send untagged data frames that are assigned to VLAN 20, while the IP phone tags its voice frames with VLAN 30. This is the standard and recommended approach for connecting an IP phone and PC to a single switch port.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
switchport mode trunk switchport trunk native vlan 20 switchport trunk allowed vlan 30
Why it's wrong here
This configuration makes the port a trunk, which would require the PC to tag its data frames with VLAN 20, but typical PCs do not support VLAN tagging. Additionally, the native VLAN is 20, so untagged frames from the PC would be placed in VLAN 20, but the phone would need to tag voice frames with VLAN 30, which is allowed. However, this is not the recommended configuration because it adds unnecessary trunking complexity and could cause security issues.
- ✗
switchport mode trunk switchport trunk native vlan 30 switchport trunk allowed vlan 20
Why it's wrong here
This configuration makes the port a trunk with native VLAN 30 and allowed VLAN 20. Untagged data frames from the PC would be placed in VLAN 30, which is incorrect. The phone would need to tag voice frames with VLAN 20, but the requirement is VLAN 30. This configuration is the opposite of what is needed.
- ✗
switchport mode access switchport access vlan 30 switchport voice vlan 20
Why it's wrong here
This configuration swaps the VLAN assignments: data VLAN 30 and voice VLAN 20. The PC's untagged data traffic would be placed in VLAN 30, not VLAN 20 as required. The phone's voice traffic would be tagged with VLAN 20, not VLAN 30. This does not meet the administrator's requirements.
- ✓
switchport mode access switchport access vlan 20 switchport voice vlan 30
Why this is correct
This configuration sets the port as an access port for data VLAN 20 and uses the voice VLAN 30 for tagged voice traffic. The phone will receive untagged data frames on VLAN 20 and will tag its voice frames with VLAN 30. This is the standard Cisco configuration for a port connecting to an IP phone with a PC behind it.
Visual reference
Go deeper
Related to this question
Learn chapter
Puppet and Chef for Network Automation
Key term
Voice VLAN
A Voice VLAN is a separate virtual local area network configured on a network switch to carry voice traffic, such as from IP phones, ensuring quality of service and security by isolating it from data traffic.
Key term
Switch
A switch is a networking device that connects devices on a local area network and uses MAC addresses to forward data only to the intended recipient.
About these practice questions
This 200-301 question is part of Courseiva's 1,450-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 200-301 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 200-301 exam.