CCNA Switching and Network Access Practice Question
Network Topology
Refer to the exhibit. A network engineer is troubleshooting an EtherChannel on R1 that is not passing traffic. The output of the show etherchannel summary command is displayed. What is the most likely cause?
⚠ Common exam trap
Cisco often tests the misconception that LACP passive/active is incompatible, but the real trap is confusing static mode 'on' (which disables negotiation) with LACP modes, leading candidates to overlook the protocol mismatch between LACP and static configuration.
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
✓
One side is configured with LACP active and the other side is configured with mode 'on' (static).
The 'show etherchannel summary' output shows the port-channel is down (flags indicate 'D' for down), and the most common cause when one side is configured with LACP active and the other with mode 'on' (static) is a protocol mismatch. LACP active expects to negotiate with another LACP-enabled port, but static mode 'on' forces the link up without negotiation, causing the EtherChannel to fail to form. This mismatch prevents the exchange of LACP frames, leaving the bundle in an error-disabled or non-functional state.
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 local switch is configured with LACP passive while the remote switch is set to LACP active.
Why it's wrong here
LACP passive mode is a valid negotiating mode and is designed to pair with an active neighbor. In a passive-active configuration, the active switch initiates LACP PDUs and the passive switch responds, allowing both sides to aggregate ports into a bundled channel. The output shows member ports flagged D, which means the physical link is down or the port was administratively shut down, not that negotiation is pending. Therefore, a passive-active LACP pair would appear as bundled (P) members, not D, so this cannot be the misconfiguration shown.
- ✓
One side is configured with LACP active and the other side is configured with mode 'on' (static).
Why this is correct
With LACP active on one side and mode 'on' on the fabric peer, the 'on' port forces an EtherChannel statically and never transmits LACP PDUs, so the active LACP port never receives a response and cannot move the member port to a bundled state. The port-channel interface may still be administratively up and declared up (SU) because it exists in configuration, but the physical member ports remain in a down (D) state because no LACP negotiation completed. This exact combination produces the (D) flags on member ports while the port-channel itself remains up, making it the correct cause.
- ✗
The remote switch is configured with PAgP desirable while the local switch uses LACP.
Why it's wrong here
A PAgP vs LACP mismatch would typically result in suspended ports (indicated by (s) or (I)), not the (D) down state shown, and the protocol column would likely show NONE or flags for mismatch. The (D) state suggests the physical link is down, not suspended due to protocol mismatch.
- ✗
The port-channel member interfaces are configured as access ports, preventing LACP from negotiating.
Why it's wrong here
LACP operates independently of the Layer 2 access or trunk mode, because LACP PDUs are sent to the well-known multicast address 01:80:c2:00:00:02 directly over the physical link before any VLAN tagging or access-port filtering is applied. Configuring an interface as an access port only affects the allowed VLAN and 802.1Q tagging; it has no bearing on whether LACP packets are exchanged. Therefore, access-port configuration cannot block LACP negotiation or cause the member ports to show a (D) down state, so this option is incorrect.
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.
✓One side is configured with LACP active and the other side is configured with mode 'on' (static).Correct answer▾
Why this is correct
With LACP active on one side and mode 'on' on the fabric peer, the 'on' port forces an EtherChannel statically and never transmits LACP PDUs, so the active LACP port never receives a response and cannot move the member port to a bundled state. The port-channel interface may still be administratively up and declared up (SU) because it exists in configuration, but the physical member ports remain in a down (D) state because no LACP negotiation completed. This exact combination produces the (D) flags on member ports while the port-channel itself remains up, making it the correct cause.
✗The local switch is configured with LACP passive while the remote switch is set to LACP active.Wrong answer — click to see why▾
Why this is wrong here
LACP passive is not incompatible with LACP active.
✗The remote switch is configured with PAgP desirable while the local switch uses LACP.Wrong answer — click to see why▾
Why this is wrong here
PAgP/LACP mismatch leads to suspended state, not down; the exhibit's (D) indicates the link is not up, which points to LACP negotiation failure rather than protocol mismatch.
✗The port-channel member interfaces are configured as access ports, preventing LACP from negotiating.Wrong answer — click to see why▾
Why this is wrong here
LACP negotiation is independent of the access/trunk configuration.
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?”
Go deeper
Related to this question
Learn chapter
Interpreting Packet Capture Output for Layer 2/3 Troubleshooting
Key term
EtherChannel
EtherChannel is a technology that bundles multiple physical Ethernet links into a single logical link to increase bandwidth and provide redundancy.
Key term
LACP
LACP is a protocol that automatically combines multiple physical network links into a single logical link to increase bandwidth and provide redundancy.
About these practice questions
One of 1,389 original 200-301 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. 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.