The answer is Link Aggregation Control Protocol (LACP). LACP is the correct choice because it enables you to combine multiple physical Ethernet links between two switches into a single logical bundle, which increases the total available bandwidth while providing automatic fault tolerance—if one link in the bundle fails, traffic is seamlessly redistributed across the remaining active links. On the CompTIA Network+ N10-009 exam, this concept tests your understanding of link aggregation and redundancy, often appearing in scenario-based questions where an administrator needs both higher throughput and link-level resilience. A common trap is confusing LACP with static link aggregation (which lacks the negotiation and dynamic failover that LACP provides) or with Spanning Tree Protocol, which blocks redundant links rather than combining them. Remember the mnemonic: LACP Links Aggregate, Combine, Protect.
N10-009 Network Implementation Practice Question
This N10-009 practice question tests your understanding of network implementation. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 administrator is connecting two switches and wants to increase the bandwidth between them while also providing redundancy in case one link fails. Which technology should be configured on the switch ports?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Link Aggregation Control Protocol (LACP)
Link Aggregation Control Protocol (LACP) allows multiple physical links between two switches to be combined into a single logical link, increasing aggregate bandwidth and providing redundancy: if one physical link fails, traffic continues over the remaining links. This directly meets the requirement for both higher bandwidth and link-level fault tolerance.
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.
✗
Spanning Tree Protocol (STP)
Why it's wrong here
STP prevents loops in redundant topologies but does not combine links to increase bandwidth. It may block redundant links.
✓
Link Aggregation Control Protocol (LACP)
Why this is correct
LACP negotiates the bundling of physical ports into a single logical link, providing increased throughput and failover.
Related concept
Read the scenario before looking for a memorised answer.
✗
VLAN trunking (802.1Q)
Why it's wrong here
Trunking allows multiple VLANs to traverse a single link but does not aggregate bandwidth or provide redundancy by itself.
✗
Power over Ethernet (PoE)
Why it's wrong here
PoE delivers power over Ethernet cables and has no effect on bandwidth aggregation or link redundancy.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse STP's loop prevention with redundancy, but STP actively blocks redundant links to avoid loops, whereas LACP allows all links to forward traffic simultaneously while still providing failover.
Detailed technical explanation
How to think about this question
LACP, defined in IEEE 802.3ad, uses Link Aggregation Groups (LAGs) where frames are distributed across member links based on a hash algorithm (e.g., source/destination MAC or IP). A real-world scenario: in a data center, four 10 GbE links aggregated via LACP yield a 40 GbE logical link, and if one cable fails, traffic is redistributed across the remaining three without STP blocking any port.
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 help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
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: Link Aggregation Control Protocol (LACP) — Link Aggregation Control Protocol (LACP) allows multiple physical links between two switches to be combined into a single logical link, increasing aggregate bandwidth and providing redundancy: if one physical link fails, traffic continues over the remaining links. This directly meets the requirement for both higher bandwidth and link-level fault tolerance.
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.
About these practice questions
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Variation 1. A network administrator is connecting two switches to increase bandwidth and provide redundancy. Which technology should be used to combine multiple physical links into a single logical link?
medium
A.Spanning Tree Protocol
✓ B.Link Aggregation Control Protocol
C.VLAN Trunking Protocol
D.Rapid Spanning Tree Protocol
Why B: Link Aggregation Control Protocol (LACP) is the correct technology because it allows multiple physical Ethernet links to be combined into a single logical link, increasing aggregate bandwidth and providing redundancy. LACP (IEEE 802.3ad) automatically negotiates and manages the bundling of ports between switches, ensuring that traffic is load-balanced across the member links and that the bundle remains operational even if one physical link fails.
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This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 exam.
Question Discussion
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