Eth-Trunk LACP Mode: Which Statement Is True?
Short answer
C In an LACP-mode Eth-Trunk, the two devices exchange LACPDUs to negotiate and maintain the aggregation, so option C is the true statement.
Question
Key Takeaways
The question tests LACP’s control-plane signature—LACPDU exchange—and the main trap is choosing a generic forwarding statement instead of the behavior that uniquely identifies LACP mode.
This H12-811 question tests the boundary between LACP-mode link aggregation and manual load balancing. The true statement is C: both ends of an LACP Eth-Trunk exchange LACPDUs to negotiate and maintain the aggregation.
Common mistake: The most plausible wrong choice is D: active links do forward and load-balance traffic, but that is a general data-plane result and not the LACP-specific behavior being asked for; A and B are false because max active-linknumber is configurable and Huawei supports up to eight active links.
Expert Analysis
The boundary being tested
This item asks for the true statement about an Eth-Trunk in LACP mode, so the key distinction is between LACP's control-plane negotiation and the data-plane behavior of a working trunk. In LACP mode, the two peers exchange LACPDUs to negotiate which member links are selected, detect failures, and keep the aggregation synchronized. That is the defining feature that separates LACP from manual load-balancing mode, where no LACPDU exchange occurs and all member links are simply placed into forwarding.
Applying it to the options
Option C states exactly that boundary: devices at both ends exchange LACPDUs. That is true for LACP and is the reason the mode is dynamic. Option A is false because the number of active links can be controlled with max active-linknumber. Option B is false because Huawei's platform supports more than four active links, commonly up to eight, not a hard four-link ceiling. Option D says all active interfaces forward and load-balance traffic; that is a normal data-plane outcome once links are selected, but it is not the LACP-specific discriminator the question is testing, and in a single-answer item C is the decisive statement. Some comments argue that C and D are both correct; the better exam reading is that C identifies LACP itself, while D describes generic forwarding and can distract from the control-plane signature.
Verdict
The correct option is C. Look for LACPDU exchange first whenever an item asks what is special about LACP-mode link aggregation.
Exam Strategy
When an LACP-mode question appears, separate control plane from data plane: look first for LACPDU exchange and negotiation, then for active-link forwarding. Eliminate count-based distractors by recalling that max active-linknumber is configurable and Huawei Eth-Trunks support up to eight active links, not four. If the item is single-select, choose the statement that uniquely identifies LACP rather than a generic forwarding behavior; if it is explicitly multi-select, verify whether the forwarding statement is also defensible before adding it.
Frequently Asked Questions
Can the number of active links in an LACP Eth-Trunk be limited?
Do standby links forward traffic in an LACP Eth-Trunk?
What distinguishes LACP mode from manual load balancing mode?
Community Votes
100% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 3 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 3
-
Fmoura17 👍 1 Answered CThe correct answer is C. C. Devices at both ends exchange LACPDUs ✅ This is correct. LACP mode is a dynamic link aggregation mode where both ends continuously exchange LACPDUs (Link Aggregation Control Protocol Data Units) to negotiate and maintain the Eth-Trunk, detect link failures, and select active/standby interfaces automatically.
-
e9b92a4 👍 1 Answered C✅ Correct answer: C. Devices at both ends exchange LACPDUs. C. Devices at both ends exchange LACPDUs. ✅ True. This is the defining feature of LACP (IEEE 802.3ad / 802.1AX). Devices at both ends exchange LACP Data Units (LACPDUs) to negotiate link aggregation, determine active/standby links, and detect link failures.
-
Heidorn 👍 1 Answered CC AND D are correct Both devices do exchange LACPDUs in LACP mode. And all active interfaces load balance.
Reader comments & corrections
No reader corrections yet — spotted an error or have a note? Share it below.