Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A switchport connected to another switch is configured as an access port by mistake. Which symptom is most likely in a multi-VLAN design?
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
Only one VLAN is likely to pass correctly, while other VLAN traffic across the link fails
This is correct because an access port normally carries one VLAN rather than multiple VLANs.
B
Distractor review
The link automatically becomes a routed port for all VLANs
This is wrong because an access-port mistake does not convert the link into a routed port.
C
Distractor review
OSPF metrics on all routers are reset
This is wrong because OSPF metrics are unrelated to this switchport mistake.
D
Distractor review
The switch stops learning MAC addresses entirely
This is wrong because the switch can still learn MAC addresses on an access port.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is assuming that a switchport misconfigured as an access port on an inter-switch link will convert the link into a routed port or disrupt routing protocols like OSPF. In reality, the physical link remains operational, and Layer 3 protocols continue unaffected. The real issue is that only one VLAN’s traffic passes, while other VLANs are blocked, causing partial network outages. Candidates might also mistakenly believe the switch stops learning MAC addresses, but MAC learning continues normally on access ports. Recognizing that the problem is a VLAN tagging and forwarding issue, not a routing or MAC learning failure, is crucial to avoid this trap.
Technical deep dive
How to think about this question
In Cisco networking, a switchport configured as an access port carries traffic for only a single VLAN. This means that all frames entering or leaving that port are tagged or untagged as belonging to one VLAN only. In contrast, trunk ports are designed to carry traffic for multiple VLANs simultaneously by tagging frames with VLAN identifiers using protocols like IEEE 802.1Q. This fundamental difference is critical in multi-VLAN environments where inter-switch links must transport traffic for several VLANs to maintain network segmentation and communication. When a link between two switches is mistakenly configured as an access port instead of a trunk port, only the VLAN assigned to that access port will pass traffic correctly. Traffic from other VLANs will not be forwarded across the link, causing communication failures for devices in those VLANs. The physical link remains operational, which can mislead network engineers into thinking the connection is healthy. However, logically, the port restricts traffic to a single VLAN, breaking the multi-VLAN design and causing partial network outages. This misconfiguration is a common exam trap because the link appears up and active, but VLAN traffic is limited. Candidates might incorrectly assume that the link converts to a routed port or that routing protocols like OSPF are affected, which is not the case. Understanding the difference between access and trunk ports and their roles in VLAN traffic forwarding is essential for troubleshooting and designing Cisco networks that support multiple VLANs effectively.
KKey Concepts to Remember
- An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.
- A trunk port carries traffic for multiple VLANs by tagging frames with VLAN IDs using protocols like IEEE 802.1Q.
- Inter-switch links in multi-VLAN environments must be configured as trunk ports to transport all VLAN traffic correctly.
- Configuring an inter-switch link as an access port restricts traffic to a single VLAN, causing other VLANs' traffic to fail across the link.
- The physical link status remains up on an access port misconfiguration, which can obscure the VLAN traffic failure.
- Routing protocols such as OSPF are unaffected by switchport mode misconfigurations because they operate at Layer 3, not Layer 2.
- Switches continue to learn MAC addresses on access ports, so MAC address learning does not stop due to this misconfiguration.
- Exam candidates must distinguish between access and trunk port roles to avoid misinterpreting symptoms of VLAN traffic failures.
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?
An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.
What is the correct answer to this question?
The correct answer is: Only one VLAN is likely to pass correctly, while other VLAN traffic across the link fails — The most likely symptom is that only one VLAN’s traffic works correctly across the link while traffic for other VLANs fails. In plain language, an access port belongs to one VLAN in normal switching behavior. If an inter-switch link that should carry multiple VLANs is accidentally configured as an access port, the network loses the ability to transport the other VLANs. The physical link may stay up, which can make the problem seem subtle, but the logical role of the port is wrong.
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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