CCNA Switching and Network Access Practice Question
A switch interface is configured as `dynamic desirable`, and the peer interface is configured as `dynamic auto`. What is the most likely result?
⚠ Common exam trap
Be careful not to confuse DTP modes with Spanning Tree Protocol states or assume passive modes prevent trunking.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The link is likely to become a trunk.
The most likely result is that the link becomes a trunk. In simple terms, `dynamic desirable` actively tries to negotiate a trunk, while `dynamic auto` listens and responds. Because one side is willing to initiate the process, trunking can be established if the rest of the configuration is compatible. This question tests whether you know the difference between passive and active DTP behavior. The classic failure pairing is auto/auto. Desirable/auto, by contrast, is a normal path to trunk formation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The link is likely to become a trunk.
Why this is correct
Dynamic desirable is the most proactive DTP mode; it actively sends DTP frames to initiate trunk negotiation. When the remote switch port is configured as dynamic auto, it passively listens and responds to DTP, allowing the two switches to agree on trunking and place the link into trunk mode. Therefore, this pairing is a valid and expected way to form a trunk.
- ✗
The link becomes a routed port.
Why it's wrong here
A routed port is created by explicitly configuring an interface with the 'no switchport' command, which moves it from Layer 2 switchport mode to Layer 3 routed mode. DTP frames are only processed on switchports and negotiate trunking status; they do not change an interface's layer mode. Even if trunk negotiation fails, the interface remains a Layer 2 switchport, never a routed port.
When this WOULD be correct
In a different scenario where a switch interface is configured as a routed port and the peer interface is also set to routed, the link would indeed become a routed port. The question would need to specify that both interfaces are configured for routing rather than dynamic negotiation.
- ✗
All VLANs are deleted from both switches.
Why it's wrong here
DTP is a Layer 2 control protocol that only negotiates whether a switchport should operate as an access port or a trunk port. It has no mechanism to modify, delete, or alter the VLAN database; VLANs are removed only through explicit configuration or VTP deletion, not through trunk negotiation. Thus, the statement that all VLANs are deleted is factually impossible via DTP.
When this WOULD be correct
In a different scenario, if the question specified that both switches were configured to use `vlan access` mode and that a VLAN pruning command was executed, it could lead to the deletion of VLANs from the trunk, making this option correct.
- ✗
The port is immediately error-disabled.
Why it's wrong here
Error-disabled states are triggered by specific Layer 1 or Layer 2 fault conditions, such as duplex mismatch, BPDU guard violation, or port security breach. The combination of dynamic desirable and dynamic auto is a standard DTP pairing that successfully negotiates a trunk, not a fault scenario. Hence, this configuration does not cause the port to enter an err-disable state, and the link becomes operational.
When this WOULD be correct
In a different scenario, if the question specified that both interfaces were configured for Layer 3 routing and that the switch was set to operate in a routed mode, then the link could be described as a routed port. This would involve a configuration where Layer 2 switching is not intended.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The link is likely to become a trunk.Correct answer▾
Why this is correct
Dynamic desirable is the most proactive DTP mode; it actively sends DTP frames to initiate trunk negotiation. When the remote switch port is configured as dynamic auto, it passively listens and responds to DTP, allowing the two switches to agree on trunking and place the link into trunk mode. Therefore, this pairing is a valid and expected way to form a trunk.
✗The link becomes a routed port.Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because a switch interface configured as `dynamic desirable` and its peer as `dynamic auto` will negotiate a trunk link, not a routed port. Routed ports are typically configured explicitly and not through dynamic negotiation.
★ When this WOULD be the correct answer
In a different scenario where a switch interface is configured as a routed port and the peer interface is also set to routed, the link would indeed become a routed port. The question would need to specify that both interfaces are configured for routing rather than dynamic negotiation.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of how dynamic negotiation works, conflating it with routed port configurations, which can lead to confusion about the roles of switch interfaces.
✗All VLANs are deleted from both switches.Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because configuring a switch interface as `dynamic desirable` and `dynamic auto` does not lead to the deletion of VLANs; it instead allows for trunk negotiation between the switches.
★ When this WOULD be the correct answer
In a different scenario, if the question specified that both switches were configured to use `vlan access` mode and that a VLAN pruning command was executed, it could lead to the deletion of VLANs from the trunk, making this option correct.
Why candidates choose this
Candidates might choose this option due to a misunderstanding of VLAN management and trunking, confusing the negotiation process with VLAN deletion when misconfigurations occur.
✗The port is immediately error-disabled.Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because a switch interface configured as `dynamic desirable` and its peer as `dynamic auto` will negotiate a trunk link, not a routed port. Routed ports are typically configured explicitly and do not involve dynamic negotiation.
★ When this WOULD be the correct answer
In a different scenario, if the question specified that both interfaces were configured for Layer 3 routing and that the switch was set to operate in a routed mode, then the link could be described as a routed port. This would involve a configuration where Layer 2 switching is not intended.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of port roles and the assumption that dynamic configurations could lead to a routed state, especially if they confuse Layer 2 and Layer 3 concepts.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Go deeper
Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
Key term
Dynamic auto
Dynamic auto is a switchport trunking mode where the port will automatically form a trunk if it receives a trunk negotiation request from the other device, but will not actively initiate trunking.
Key term
CAN
A CAN (Controller Area Network) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer.
About these practice questions
This 200-301 question is part of Courseiva's 1,389-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.