The answer is passive mode. This is correct because LACP active and passive modes define how a switch initiates link aggregation negotiation: active mode actively sends LACP packets to form a Link Aggregation Group, while passive mode only listens and responds to those packets without initiating them. Since Switch A is set to active, Switch B must be in passive mode to complete the negotiation and successfully form the LAG. On the CompTIA Network+ N10-009 exam, this concept tests your understanding of LACP’s dynamic negotiation process, often appearing in scenario-based questions where one side must be active and the other passive to avoid a deadlock. A common trap is assuming both switches can be passive, which prevents any LACP packets from being sent. Remember the memory tip: “Active announces, Passive answers”—if one side initiates, the other must respond, not initiate.
N10-009 Network Implementation Practice Question
This N10-009 practice question tests your understanding of network implementation. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer is configuring a Link Aggregation Group (LAG) between two switches. Switch A is set to LACP active mode. Which mode should be configured on Switch B to form the LAG?
LACP passive mode will respond to negotiation requests from the active peer, forming the LAG. This is the correct complementary mode.
B
On
Why wrong: The 'on' mode creates a static LAG without LACP negotiation. It will not form a LAG with an LACP active port because no control protocol is used.
C
Static
Why wrong: Static is not a valid LACP mode; interfaces are either active, passive, or on (manual). It is a generic term often confused with manual configuration.
D
Auto
Why wrong: 'Auto' is a mode used with Cisco's PAgP (Port Aggregation Protocol), not LACP. It will not negotiate with LACP active.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Passive
LACP active mode initiates negotiation by sending LACP packets, while passive mode responds to those packets without initiating. Since Switch A is set to active, Switch B must be in passive mode to successfully form a Link Aggregation Group (LAG). This combination allows the two switches to exchange LACP frames and agree on the aggregation parameters.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Passive
Why this is correct
LACP passive mode will respond to negotiation requests from the active peer, forming the LAG. This is the correct complementary mode.
Related concept
Read the scenario before looking for a memorised answer.
✗
On
Why it's wrong here
The 'on' mode creates a static LAG without LACP negotiation. It will not form a LAG with an LACP active port because no control protocol is used.
✗
Static
Why it's wrong here
Static is not a valid LACP mode; interfaces are either active, passive, or on (manual). It is a generic term often confused with manual configuration.
✗
Auto
Why it's wrong here
'Auto' is a mode used with Cisco's PAgP (Port Aggregation Protocol), not LACP. It will not negotiate with LACP active.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between LACP modes (active/passive) and PAgP modes (desirable/auto), leading candidates to mistakenly choose 'Auto' (a PAgP mode) for LACP questions.
Trap categories for this question
Similar concept trap
Static is not a valid LACP mode; interfaces are either active, passive, or on (manual). It is a generic term often confused with manual configuration.
Detailed technical explanation
How to think about this question
LACP, defined in IEEE 802.3ad (now 802.1AX), uses active and passive modes to control negotiation. In active mode, the switch sends LACP Data Units (LACPDUs) every 1 second (fast rate) or 30 seconds (slow rate). Passive mode only responds to received LACPDUs, making it ideal for preventing loops when only one side initiates. A real-world scenario is connecting a server NIC team (active) to a switch (passive) to avoid unnecessary LACP traffic on the server.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this N10-009 question in full detail.
Network Implementation — This question tests Network Implementation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Passive — LACP active mode initiates negotiation by sending LACP packets, while passive mode responds to those packets without initiating. Since Switch A is set to active, Switch B must be in passive mode to successfully form a Link Aggregation Group (LAG). This combination allows the two switches to exchange LACP frames and agree on the aggregation parameters.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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