CCNA Switching and Network Access Practice Question
A switch port should allow an IP phone and attached PC to operate correctly. The phone should place voice traffic in VLAN 200 while the PC remains in VLAN 20. Which configuration approach best supports that design?
⚠ Common exam trap
Avoid assuming trunk mode is needed for VLANs; understand access vs. voice VLANs for edge ports.
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
✓
Configure the port with an access VLAN for data and a voice VLAN for the phone
The best approach is to configure the access VLAN for user data and the voice VLAN separately. In plain language, the PC should remain a normal untagged data endpoint in VLAN 20, while the phone can tag its own voice traffic for VLAN 200. Cisco access-port designs support this exact use case and allow the switch to keep voice and user traffic logically separated without requiring two physical ports. This is a classic CCNA edge-port design. It is not a general trunking problem, and it does not require EtherChannel or router subinterfaces. The important idea is that one switchport can support an access VLAN and a voice VLAN together in a way designed specifically for IP phones with downstream PCs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure the port with an access VLAN for data and a voice VLAN for the phone
Why this is correct
Cisco IP phones contain a small 3-port switch that places PC traffic on the configured access VLAN while the phone itself uses a distinct voice VLAN advertised via CDP. This design keeps data and voice in separate Layer 2 broadcast domains, allows separate QoS policies and subnets, and works over a single physical cable without a trunk to the desktop. The access VLAN carries untagged PC frames, while the voice VLAN uses 802.1Q tagging on the phone uplink, making coexistence correct.
- ✗
Configure the port as a routed port with no switchport
Why it's wrong here
A routed port assigned with 'no switchport' makes the interface a Layer 3 port that expects an IP address and routes packets rather than forwarding frames in VLANs. This would prevent the switch from applying the access or voice VLAN features, and the attached PC would need its own subnet separate from the phone, requiring a router instead of a simple edge switch. Cisco IP phones use L2 protocols (like CDP for voice VLAN) that only function on switchport interfaces, making a routed port incompatible with the standard phone-plus-PC deployment.
When this WOULD be correct
In a scenario where a question asks for a configuration to route traffic between different VLANs without needing Layer 2 switching, such as when connecting to a router or Layer 3 switch, configuring the port as a routed port would be appropriate.
- ✗
Configure the port as an EtherChannel member
Why it's wrong here
EtherChannel is a link-aggregation technique that combines multiple physical switch ports into one logical interface to increase bandwidth and provide redundancy, typically using LACP or PAgP. It has no effect on how a single access port should segregate IP phone and PC traffic, because the goal here is VLAN membership, not link bundling. Configuring this port as an EtherChannel member would also require a compatible peer on the phone, which is not how Cisco IP phones operate.
When this WOULD be correct
In a scenario where the question specifies that multiple switch ports need to be aggregated for increased bandwidth without the need for VLAN separation, configuring the port as an EtherChannel member would be correct. For instance, if the question states that both devices operate in the same VLAN and require load balancing, this option would be appropriate.
- ✗
Use a native VLAN only and disable all tagging
Why it's wrong here
Using only a native VLAN and disabling all tagging collapses both phone and PC into the same broadcast domain, eliminating the VLAN separation needed for voice QoS and security. The native VLAN is primarily for untagged frames on a trunk, but here there is no trunk; a single port cannot distinguish phone traffic from PC traffic without either a voice VLAN or separate physical switchports. Cisco phones also rely on CDP to receive a voice VLAN assignment, so failing to tag voice frames prevents the phone from implementing its voice VLAN configuration.
When this WOULD be correct
In a scenario where a network design requires a simple setup with only one VLAN for both voice and data traffic, and where VLAN tagging is not needed due to the network's limited complexity, this option could be correct.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Configure the port with an access VLAN for data and a voice VLAN for the phoneCorrect answer▾
Why this is correct
Cisco IP phones contain a small 3-port switch that places PC traffic on the configured access VLAN while the phone itself uses a distinct voice VLAN advertised via CDP. This design keeps data and voice in separate Layer 2 broadcast domains, allows separate QoS policies and subnets, and works over a single physical cable without a trunk to the desktop. The access VLAN carries untagged PC frames, while the voice VLAN uses 802.1Q tagging on the phone uplink, making coexistence correct.
✗Configure the port as a routed port with no switchportWrong answer — click to see why▾
Why this is wrong here
A routed port (no switchport) is used for Layer 3 routing between switches or routers, not for connecting end devices like IP phones and PCs. It does not support VLAN assignment or the coexistence of multiple VLANs on a single port, making it unsuitable for this scenario.
★ When this WOULD be the correct answer
In a scenario where a question asks for a configuration to route traffic between different VLANs without needing Layer 2 switching, such as when connecting to a router or Layer 3 switch, configuring the port as a routed port would be appropriate.
Why candidates choose this
Students might confuse a routed port with a trunk port or think that routing is needed to separate voice and data traffic, but the correct approach is to use switchport features like voice VLAN, not routed ports.
✗Configure the port as an EtherChannel memberWrong answer — click to see why▾
Why this is wrong here
EtherChannel is used to aggregate multiple physical links into a single logical link for increased bandwidth and redundancy. It does not provide any mechanism to separate voice and data traffic into different VLANs on a single port, and it is not relevant to the requirement of connecting an IP phone and PC.
★ When this WOULD be the correct answer
In a scenario where the question specifies that multiple switch ports need to be aggregated for increased bandwidth without the need for VLAN separation, configuring the port as an EtherChannel member would be correct. For instance, if the question states that both devices operate in the same VLAN and require load balancing, this option would be appropriate.
Why candidates choose this
A test-taker might think that EtherChannel can be used to carry multiple VLANs, but that is the function of a trunk, not EtherChannel. EtherChannel itself does not affect VLAN assignment; it simply bundles links.
✗Use a native VLAN only and disable all taggingWrong answer — click to see why▾
Why this is wrong here
Using a native VLAN only and disabling all tagging would place all traffic (voice and data) in the same VLAN, which contradicts the requirement to separate voice into VLAN 200 and data into VLAN 20. The native VLAN is used for untagged traffic on a trunk, but this design requires distinct VLANs with tagging for voice.
★ When this WOULD be the correct answer
In a scenario where a network design requires a simple setup with only one VLAN for both voice and data traffic, and where VLAN tagging is not needed due to the network's limited complexity, this option could be correct.
Why candidates choose this
Students may think that the native VLAN can be used to carry both voice and data without tagging, but that would not achieve VLAN separation. The voice VLAN feature specifically uses tagging for voice traffic while keeping data untagged in the access VLAN.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
Key term
Switchport
A switchport is a physical or virtual interface on a network switch that connects devices like computers, printers, or other switches to a local area network.
Key term
Link Aggregation Control Protocol
Link Aggregation Control Protocol (LACP) is a standard protocol that automatically bundles multiple physical network links into a single logical link to increase bandwidth and provide redundancy.
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