CCNA Switching and Network Access Practice Question
A switch port connected to an IP phone and a PC should separate voice traffic from data traffic while still using one physical edge connection. Which feature best supports that design?
⚠ Common exam trap
Avoid confusing the purpose of trunk ports and link aggregation with traffic separation on a single edge port.
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
✓
Voice VLAN
A voice VLAN best supports that design. In practical terms, a Cisco-style voice VLAN allows the switch to carry voice traffic separately from user data even though the phone and PC share the same physical access connection. This is a common enterprise edge design because it lets the phone use one VLAN while the downstream PC uses another. The key point is separation of traffic types over one edge port, not trunking between switches or link aggregation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Voice VLAN
Why this is correct
A voice VLAN is the correct solution because it enables a single access port to carry both IP phone traffic and PC data while keeping them logically distinct. The Cisco IP phone tags its signaling and media frames with the 802.1Q voice VLAN ID, whereas the PC's untagged frames remain in the data VLAN, allowing the switch to apply separate QoS and security policies for each traffic type.
- ✗
EtherChannel
Why it's wrong here
EtherChannel bundles two to eight physical links into one logical link to increase aggregate bandwidth or provide link redundancy, not to distinguish or separate traffic classes on a single edge port. A phone and PC that share one switch port represent a single physical connection, so there are no multiple links to aggregate, and EtherChannel has no mechanism to classify voice frames versus data frames. Therefore, this option fails to address the need for voice/data separation at the port level.
When this WOULD be correct
In a scenario where the question asks about increasing bandwidth for a server connection without the need for traffic separation, EtherChannel would be the correct answer. For example, a question might ask how to combine multiple links to a server for higher throughput without regard to VLANs.
- ✗
Native VLAN
Why it's wrong here
Native VLAN is a trunk-port mechanism that designates which VLAN is carried without an 802.1Q tag on a trunk link; it does not create any special handling for voice frames on an access port connected to a phone and PC. If the native VLAN were used for voice, the phone's traffic would be untagged and would pass into the same broadcast domain as the PC's data, completely defeating the isolation this question requires. Thus, this option is incorrect because it misapplies a trunking concept to an edge-port separation scenario.
When this WOULD be correct
In a question asking about configuring a trunk link where untagged traffic must be handled, such as when connecting multiple switches that require a common VLAN for management traffic, Native VLAN would be the correct choice.
- ✗
Loop guard
Why it's wrong here
Loop guard is a Spanning Tree Protocol enhancement that protects against Layer 2 forwarding loops caused by unidirectional link failures, typically by placing non-designated ports into an inconsistent state when BPDUs stop arriving. It operates at the STP topology level and has no ability to classify or partition the different frame types arriving on a shared access port. This option is wrong because it solves a loop-prevention problem, not the VLAN-based voice/data isolation described in the question.
When this WOULD be correct
In a question asking about enhancing network stability and preventing broadcast storms in a redundant switch topology, loop guard would be the correct answer. For example, if the question specified a scenario where network loops were a concern, loop guard would be essential to maintain network integrity.
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.
✓Voice VLANCorrect answer▾
Why this is correct
A voice VLAN is the correct solution because it enables a single access port to carry both IP phone traffic and PC data while keeping them logically distinct. The Cisco IP phone tags its signaling and media frames with the 802.1Q voice VLAN ID, whereas the PC's untagged frames remain in the data VLAN, allowing the switch to apply separate QoS and security policies for each traffic type.
✗EtherChannelWrong 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, but it does not inherently separate voice and data traffic on a single port. It does not address the requirement of managing different traffic types on the same physical connection.
★ When this WOULD be the correct answer
In a scenario where the question asks about increasing bandwidth for a server connection without the need for traffic separation, EtherChannel would be the correct answer. For example, a question might ask how to combine multiple links to a server for higher throughput without regard to VLANs.
Why candidates choose this
Candidates may be tempted by EtherChannel because it involves network traffic management and can be associated with optimizing connections, leading them to mistakenly believe it relates to separating voice and data traffic.
✗Native VLANWrong answer — click to see why▾
Why this is wrong here
The Native VLAN is used for untagged traffic on a trunk link and does not separate voice and data traffic effectively; it simply allows untagged frames to pass through without any differentiation.
★ When this WOULD be the correct answer
In a question asking about configuring a trunk link where untagged traffic must be handled, such as when connecting multiple switches that require a common VLAN for management traffic, Native VLAN would be the correct choice.
Why candidates choose this
Candidates may confuse Native VLAN with the concept of VLANs in general, mistakenly thinking it can also manage voice and data separation, leading them to choose it as a viable option.
✗Loop guardWrong answer — click to see why▾
Why this is wrong here
Loop guard is designed to prevent loops in a switched network by blocking ports that receive unexpected BPDUs. It does not facilitate the separation of voice and data traffic on a single physical connection, which is the requirement of the question.
★ When this WOULD be the correct answer
In a question asking about enhancing network stability and preventing broadcast storms in a redundant switch topology, loop guard would be the correct answer. For example, if the question specified a scenario where network loops were a concern, loop guard would be essential to maintain network integrity.
Why candidates choose this
Candidates may choose loop guard because they recognize it as a feature related to switch port configuration and may confuse its role in maintaining network stability with the need to manage traffic types, leading to a misapplication of its function.
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
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.
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.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.