Quick Answer
The answer is the switch, because VLAN traffic separation is a Layer 2 function performed directly by the switch. A switch uses IEEE 802.1Q tagging to assign each port to a specific VLAN, such as VLAN10 or VLAN20, creating isolated broadcast domains so frames from one VLAN never reach ports in another without a router. On the CompTIA ITF+ exam, this concept tests your understanding that VLANs operate at the data link layer, and a common trap is assuming a router or firewall handles this separation—routers only route between VLANs, not separate them. Remember that the switch is the gatekeeper for VLAN traffic; it tags and isolates frames at the port level. A helpful memory tip: “Switch separates, Router connects”—the switch keeps VLANs apart, while the router bridges them when needed.
This FC0-U61 practice question tests your understanding of it concepts and terminology. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Refer to the exhibit. Architecture diagram: Internet -> Firewall -> Router -> Switch -> VLAN10 (Sales) and VLAN20 (Engineering).
Based on the exhibit, which device is directly responsible for separating traffic into VLAN10 and VLAN20?
Refer to the exhibit. Architecture diagram: Internet -> Firewall -> Router -> Switch -> VLAN10 (Sales) and VLAN20 (Engineering).
Firewall
Why wrong: The firewall filters traffic but does not create VLANs.
Internet
Why wrong: The internet is an external network, not a device.
Router
Why wrong: The router routes traffic between VLANs but does not separate them.
Switch
Switches are used to create and separate VLANs.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Switch
The switch is directly responsible for separating traffic into VLAN10 and VLAN20 because VLANs are configured at Layer 2 on a switch, using VLAN tagging (IEEE 802.1Q) to isolate broadcast domains. The switch assigns each port to a specific VLAN, ensuring that frames from VLAN10 are not forwarded to VLAN20 ports without a Layer 3 device.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Firewall
Why it's wrong here
The firewall filters traffic but does not create VLANs.
Internet
Why it's wrong here
The internet is an external network, not a device.
Router
Why it's wrong here
The router routes traffic between VLANs but does not separate them.
Switch
Why this is correct
Switches are used to create and separate VLANs.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often confuse the switch's role in VLAN creation with the router's role in inter-VLAN routing, assuming the router separates the VLANs when it only routes between them after the switch has already isolated them.
Detailed technical explanation
VLANs are implemented by tagging Ethernet frames with a 4-byte VLAN tag (IEEE 802.1Q), which includes a 12-bit VLAN ID (0-4095). The switch uses a VLAN table to map ports to VLANs, and frames are only forwarded to ports in the same VLAN unless a router or Layer 3 switch performs inter-VLAN routing. In real-world networks, misconfigured trunk ports (e.g., allowing all VLANs) can accidentally leak traffic between VLANs, breaking isolation.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
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FAQ
IT Concepts and Terminology — This question tests IT Concepts and Terminology — Read the scenario before looking for a memorised answer..
The correct answer is: Switch — The switch is directly responsible for separating traffic into VLAN10 and VLAN20 because VLANs are configured at Layer 2 on a switch, using VLAN tagging (IEEE 802.1Q) to isolate broadcast domains. The switch assigns each port to a specific VLAN, ensuring that frames from VLAN10 are not forwarded to VLAN20 ports without a Layer 3 device.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
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