Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A switchport on one side of a link is configured as a trunk, but the peer side is configured as an access port. What is the most likely result?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
The link roles are mismatched, so VLAN traffic will not be handled as intended.
This is correct because trunk/access disagreement creates a logical mismatch.
B
Distractor review
The access side automatically becomes a routed port.
This is wrong because a trunk/access mismatch does not convert the port into Layer 3 mode.
C
Distractor review
Both switches automatically synchronize their switchport settings.
This is wrong because switchport configuration is not automatically synchronized that way.
D
Distractor review
The mismatch forces OSPF to change router IDs.
This is wrong because OSPF router-ID behavior is unrelated to a Layer 2 switchport mismatch.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is assuming that a trunk/access mismatch will cause the link to go down or convert the port into a routed interface. Candidates may also incorrectly believe that switches automatically synchronize trunk and access settings or that routing protocols like OSPF adjust router IDs due to Layer 2 mismatches. In reality, the physical link stays up, but VLAN traffic is mishandled, causing connectivity issues that are not immediately obvious. Misinterpreting these symptoms can lead to incorrect troubleshooting and exam answers.
Technical deep dive
How to think about this question
In Cisco switching environments, a trunk port is designed to carry traffic for multiple VLANs by tagging frames with IEEE 802.1Q tags. This tagging allows switches to differentiate between VLANs across a single physical link. Conversely, an access port is configured to carry traffic for a single VLAN and does not tag frames. When one side of a link is set as a trunk and the other as an access port, the two ends have fundamentally different expectations about frame tagging and VLAN handling. The decision process in Cisco switches for trunk and access ports is strict: a trunk port expects to receive and send tagged frames for multiple VLANs, while an access port expects untagged frames belonging to a single VLAN. This mismatch causes a logical disagreement where the trunk side tags frames but the access side strips or ignores tags, leading to VLAN traffic not being properly forwarded or recognized. The link may remain physically up, but VLAN separation and traffic forwarding fail, causing connectivity issues. This scenario is a common exam trap because the physical link status may appear operational, misleading candidates to think the configuration is correct. However, the logical mismatch prevents proper VLAN communication. In practical networks, this mismatch can cause intermittent connectivity or VLAN leakage issues. Understanding this behavior helps network engineers troubleshoot VLAN problems and ensures consistent switchport configuration across links to maintain VLAN integrity.
KKey Concepts to Remember
- A trunk port carries traffic for multiple VLANs by tagging frames with IEEE 802.1Q tags to distinguish VLAN membership.
- An access port carries traffic for a single VLAN and sends untagged frames without VLAN tags.
- A trunk/access mismatch causes a logical disagreement where VLAN tagging expectations differ, preventing proper VLAN traffic forwarding.
- Switchports configured as trunks expect tagged frames, while access ports expect untagged frames, leading to traffic handling conflicts if mismatched.
- The physical link may remain up during a trunk/access mismatch, but VLAN traffic will not be handled as intended.
- Cisco switches do not automatically synchronize switchport modes between connected devices, requiring manual configuration consistency.
- OSPF router IDs and Layer 3 routing behavior are unrelated to Layer 2 switchport trunk/access configuration mismatches.
- A trunk/access mismatch does not convert a switchport into a routed port; it remains a Layer 2 interface with conflicting VLAN handling.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
A trunk port carries traffic for multiple VLANs by tagging frames with IEEE 802.1Q tags to distinguish VLAN membership.
What is the correct answer to this question?
The correct answer is: The link roles are mismatched, so VLAN traffic will not be handled as intended. — The most likely result is a logical mismatch that prevents VLAN traffic from crossing the link as intended. In practical terms, one side is trying to carry multiple VLANs with tagging behavior, while the other side is treating the connection as a normal one-VLAN endpoint port. That disagreement usually leads to unexpected or failed traffic behavior. This is a classic switching mismatch scenario. The link may still be physically up, but the two sides do not agree on how the traffic should be handled.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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