For CCNA VLAN practice questions, start by drawing the path the traffic must take. Label each host’s access VLAN, the link between switches, and any routing function. That sketch often reveals whether a proposed answer addresses the actual problem.
Cisco’s access and trunk port explanation distinguishes a port assigned to one VLAN from a trunk capable of carrying several. The original scenarios below use a simplified data network to practise that distinction.
Question 1: Two hosts, different VLANs
Host A connects to an access port in VLAN 10. Host B connects to an access port in VLAN 20 on the same Layer 2 switch. No router, Layer 3 switching function, or other path connects those VLANs. Does attaching both hosts to that physical switch provide communication between the VLANs?
Answer: No. The shared device does not remove the logical separation. The scenario explicitly provides no routing path between the VLANs. Cisco includes inter-VLAN routing among its CCNA training topics; keep that function separate from simply placing ports on a switch.
In your diagram, mark the missing routing path. That is more informative than writing “VLAN problem,” which could describe several unrelated faults.
Revisit the CCNA study guide if you can recognize VLAN terminology but cannot explain the distinctions behind a scenario.
Question 2: The trunk excludes the required VLAN
Now place two hosts in VLAN 10, one on each of two switches. Assume their IP settings, host firewalls, access-port assignments, and physical links are correct, and no alternate path exists. The inter-switch link is an operational trunk but permits only VLAN 20. Can VLAN 10 traffic cross that link as configured?
Answer: No. The trunk is present, but the permitted VLAN list excludes VLAN 10. “The trunk is up” does not establish that it carries the VLAN needed by this traffic.
Your first follow-up in a training lab should be to inspect the allowed and active VLANs along the path. Do not propose changing every VLAN setting at once; that would make the cause harder to isolate.
Question 3: What changes when the missing VLAN is permitted?
Keep the second scenario’s assumptions and permit VLAN 10 on the operational inter-switch trunk. VLAN 10 now has the required path between the switches. The change resolves the specific exclusion described; it does not prove that every possible fault in a real network has been checked.
For a variation, move one host’s access port to VLAN 20 while leaving the other in VLAN 10. Explain why fixing the trunk alone would no longer answer the new scenario. The changed detail should change your reasoning.
Turn the answer into a verification task
Use CCNA practice questions on Every Exam Prep to practise identifying those deciding details. For each answer, note what you would inspect in a simulator or authorized lab to confirm your explanation.
Keep observations separate from assumptions. “The link indicator is active” is an observation; “the necessary VLAN is permitted across it” needs its own verification. That distinction makes your review useful beyond a familiar diagram and helps you reason through the next question when the host locations or VLAN numbers change.