The answer is that the AP is operating in 802.11ac mode with 80 MHz channel bonding, which causes high interference in the dense environment. This is correct because wider channel widths like 80 MHz increase the likelihood of co-channel interference and overlapping basic service sets (OBSS), degrading throughput even when clients are close to the AP. On the CCNA 200-301 v2 exam, this tests your understanding of how wireless channel width performance in dense environments is directly impacted by the trade-off between speed and interference—a common trap is assuming wider channels always improve throughput. Remember that in crowded spaces, narrower 20 or 40 MHz channels with 802.11ax’s OFDMA and spatial reuse actually deliver better real-world performance. A useful memory tip: “Wide is fast in the clear, narrow is king when the air is thick.”
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. 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.
Exhibit
AP Name : AP9130-01
MAC Address : aabb.cc00.0100
Admin State : ENABLED
Operational State : UP
Channel Width : 80 MHz
Channel : 36
DFS Status : DFS-NON-COMPLIANT
Primary Channel : 36
Secondary Channel : 40
Radio Band : 5 GHz
Client Count : 25
Utilization : 75%
Interference : HIGH
Power Level : 1 (Maximum)
Antenna Type : Internal
Antenna Gain : 4 dBi
802.11 Protocol : 802.11ac
Beacon Interval : 100 TU
DTIM Period : 2
Supported Data Rates : 6,9,12,18,24,36,48,54 Mbps
MCS Rates : 0-9 (HT), 0-9 (VHT)
QoS Parameters : WMM Enabled
Security : WPA2-PSK
Rogue Detection : Enabled
A network engineer is troubleshooting a wireless performance issue in a dense office environment. Clients on the 5 GHz band are experiencing low throughput even though they are close to the AP. The AP is a Cisco 9130AXI running IOS-XE 17.9. What is the most likely cause of the poor performance?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
AP Name : AP9130-01
MAC Address : aabb.cc00.0100
Admin State : ENABLED
Operational State : UP
Channel Width : 80 MHz
Channel : 36
DFS Status : DFS-NON-COMPLIANT
Primary Channel : 36
Secondary Channel : 40
Radio Band : 5 GHz
Client Count : 25
Utilization : 75%
Interference : HIGH
Power Level : 1 (Maximum)
Antenna Type : Internal
Antenna Gain : 4 dBi
802.11 Protocol : 802.11ac
Beacon Interval : 100 TU
DTIM Period : 2
Supported Data Rates : 6,9,12,18,24,36,48,54 Mbps
MCS Rates : 0-9 (HT), 0-9 (VHT)
QoS Parameters : WMM Enabled
Security : WPA2-PSK
Rogue Detection : Enabled
A
The AP is using an incorrect channel width of 80 MHz, which is not supported by 802.11ac.
Why wrong: 802.11ac does support 80 MHz channel bonding (and up to 160 MHz), so this is not the issue.
B
The AP is operating in 802.11ac mode instead of 802.11ax, and the 80 MHz channel bonding is causing high interference in the dense environment.
802.11ax (Wi-Fi 6) uses OFDMA to reduce interference and improve efficiency in dense environments. The AP is using 802.11ac with 80 MHz channel bonding, which is more prone to interference, leading to poor throughput.
C
The AP has DFS non-compliance, which prevents it from using channel 36 and causes the radio to operate at reduced power.
Why wrong: DFS non-compliance means the AP is not properly detecting radar, but it does not necessarily reduce power; it may cause the AP to avoid certain channels. The power level is set to maximum (1), so power reduction is not the issue.
D
The AP is using WPA2-PSK instead of WPA3, which causes lower throughput due to weaker encryption.
Why wrong: WPA2-PSK does not inherently reduce throughput compared to WPA3; encryption overhead is negligible. The performance issue is due to interference and protocol choice, not security.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The AP is operating in 802.11ac mode instead of 802.11ax, and the 80 MHz channel bonding is causing high interference in the dense environment.
Option B is correct because in a dense office environment, using 80 MHz channel bonding with 802.11ac (Wave 2) increases the likelihood of co-channel interference and overlapping basic service sets (OBSS), which degrades throughput despite strong signal. The Cisco 9130AXI supports 802.11ax (Wi-Fi 6), which includes OFDMA and better spatial reuse, but if the AP is configured for 802.11ac mode, it loses these efficiency gains and suffers from the wide channel's interference penalty.
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.
✗
The AP is using an incorrect channel width of 80 MHz, which is not supported by 802.11ac.
Why it's wrong here
802.11ac does support 80 MHz channel bonding (and up to 160 MHz), so this is not the issue.
✓
The AP is operating in 802.11ac mode instead of 802.11ax, and the 80 MHz channel bonding is causing high interference in the dense environment.
Why this is correct
802.11ax (Wi-Fi 6) uses OFDMA to reduce interference and improve efficiency in dense environments. The AP is using 802.11ac with 80 MHz channel bonding, which is more prone to interference, leading to poor throughput.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The AP has DFS non-compliance, which prevents it from using channel 36 and causes the radio to operate at reduced power.
Why it's wrong here
DFS non-compliance means the AP is not properly detecting radar, but it does not necessarily reduce power; it may cause the AP to avoid certain channels. The power level is set to maximum (1), so power reduction is not the issue.
✗
The AP is using WPA2-PSK instead of WPA3, which causes lower throughput due to weaker encryption.
Why it's wrong here
WPA2-PSK does not inherently reduce throughput compared to WPA3; encryption overhead is negligible. The performance issue is due to interference and protocol choice, not security.
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 AP is operating in 802.11ac mode instead of 802.11ax, and the 80 MHz channel bonding is causing high interference in the dense environment.Correct answer▾
Why this is correct
802.11ax (Wi-Fi 6) uses OFDMA to reduce interference and improve efficiency in dense environments. The AP is using 802.11ac with 80 MHz channel bonding, which is more prone to interference, leading to poor throughput.
✗The AP is using an incorrect channel width of 80 MHz, which is not supported by 802.11ac.Wrong answer — click to see why▾
Why this is wrong here
802.11ac supports 80 MHz channel bonding, so this is not incorrect.
✗The AP has DFS non-compliance, which prevents it from using channel 36 and causes the radio to operate at reduced power.Wrong answer — click to see why▾
Why this is wrong here
DFS non-compliance does not directly reduce power; it may cause channel avoidance, but the power is set to maximum.
✗The AP is using WPA2-PSK instead of WPA3, which causes lower throughput due to weaker encryption.Wrong answer — click to see why▾
Why this is wrong here
WPA2-PSK does not cause throughput degradation; the issue is interference and protocol mode.
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?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that wider channels always improve performance, when in reality, in dense environments, 80 MHz or 160 MHz channels cause severe interference and throughput degradation, especially with 802.11ac's lack of spatial reuse mechanisms.
Detailed technical explanation
How to think about this question
802.11ac uses wider channels (80 or 160 MHz) to increase peak data rates, but in dense deployments, each 80 MHz channel consumes four 20 MHz subchannels, drastically reducing the number of non-overlapping channels (only two in 5 GHz UNII-1/3) and increasing contention. 802.11ax (Wi-Fi 6) mitigates this with OFDMA, which allows multiple clients to share a channel simultaneously, and BSS coloring to reduce co-channel interference, but these features are unavailable when the AP operates in 802.11ac mode. The 'show ap dot11 5ghz summary' command would reveal the operational mode and channel width, making the mismatch clear.
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 200-301 question in full detail.
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The AP is operating in 802.11ac mode instead of 802.11ax, and the 80 MHz channel bonding is causing high interference in the dense environment. — Option B is correct because in a dense office environment, using 80 MHz channel bonding with 802.11ac (Wave 2) increases the likelihood of co-channel interference and overlapping basic service sets (OBSS), which degrades throughput despite strong signal. The Cisco 9130AXI supports 802.11ax (Wi-Fi 6), which includes OFDMA and better spatial reuse, but if the AP is configured for 802.11ac mode, it loses these efficiency gains and suffers from the wide channel's interference penalty.
What should I do if I get this 200-301 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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