Question 1mediummultiple choice
Full question →A switch shows this output:
Gi0/1 on 802.1q trunking 1 Gi0/2 auto n-802.1q trunking 1
Which statement is correct?
mediummultiple choiceObjective-mapped
A switch shows this output:
Gi0/1 on 802.1q trunking 1 Gi0/2 auto n-802.1q trunking 1
Which statement is correct?
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
Distractor review
Gi0/1 is an access port in VLAN 1
The output explicitly shows Gi0/1 trunking, not access mode.
B
Best answer
Gi0/1 is trunking, and Gi0/2 is waiting for DTP negotiation
Correct. Gi0/1 is trunking now; Gi0/2 is in a passive DTP negotiation state.
C
Distractor review
Gi0/2 is forced to trunk mode
Dynamic auto does not force trunking by itself.
D
Distractor review
Neither interface can carry tagged traffic
A working 802.1Q trunk absolutely can carry tagged traffic.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is assuming that dynamic auto mode forces a port to trunk. Many candidates mistakenly believe that dynamic auto ports will become trunk ports automatically. However, dynamic auto is a passive mode that waits for the other side to actively request trunking. If both sides are set to dynamic auto or access, the link remains an access port, not trunking. This misunderstanding can lead to incorrect answers about interface states and VLAN tagging behavior in Cisco switches.
Technical deep dive
How to think about this question
802.1Q trunking is a VLAN tagging protocol used on Cisco switches to carry multiple VLANs over a single physical link. A trunk port tags Ethernet frames with VLAN identifiers, allowing traffic from multiple VLANs to traverse the same interface. Cisco switches use Dynamic Trunking Protocol (DTP) to negotiate trunk links automatically, with interface modes such as trunk, access, dynamic desirable, and dynamic auto determining how the port behaves in trunk negotiation. In the given output, Gi0/1 is explicitly trunking using 802.1Q, meaning it is actively tagging frames for VLAN 1 and potentially other VLANs. Gi0/2 is in dynamic auto mode, which means it passively waits for the other side to initiate trunk negotiation. If the other side does not actively request trunking, Gi0/2 remains an access port. This behavior is fundamental to understanding how Cisco switches establish trunk links dynamically. The exam trap here is confusing dynamic auto mode with forced trunking. Dynamic auto ports do not actively negotiate trunking; they wait for the peer to initiate. This can cause a link to remain in access mode if the other side is also passive or set to access. Understanding this subtlety helps avoid misinterpreting interface states and ensures correct VLAN traffic flow in practical networks and exam scenarios.
KKey Concepts to Remember
- 802.1Q trunking tags Ethernet frames to carry multiple VLANs over a single physical link on Cisco switches.
- Dynamic Trunking Protocol (DTP) negotiates trunk links automatically using interface modes like trunk, access, dynamic desirable, and dynamic auto.
- A port in dynamic auto mode passively waits for the other side to initiate trunk negotiation before becoming a trunk port.
- A port in trunk mode actively tags frames and carries traffic for multiple VLANs without waiting for negotiation.
- If both ends of a link are set to dynamic auto or access, the link remains an access port and does not trunk.
- Dynamic desirable mode actively attempts to form a trunk by sending DTP negotiation frames to the peer.
- Understanding interface modes and their negotiation behavior is essential to correctly interpret switch port states and VLAN traffic flow.
- Misinterpreting dynamic auto as forced trunking is a common exam mistake that leads to incorrect conclusions about port states.
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?
802.1Q trunking tags Ethernet frames to carry multiple VLANs over a single physical link on Cisco switches.
What is the correct answer to this question?
The correct answer is: Gi0/1 is trunking, and Gi0/2 is waiting for DTP negotiation — Gi0/1 is already operating as an 802.1Q trunk. Gi0/2 is in dynamic auto mode, which waits for the other side to actively negotiate trunking.
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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