Max client count for Cisco 9120 and 9130 AP

[vinitgori1]

What is the max client count that is recommended for cisco 9120 and 9130 AP operating on wifi 6 with which I can except a decent performance.

Could someone please help me with this query?

[marce1000]

- I think there is no unique answer. It will depend on the traffic
generated by client-apps and the surrounding density of the wireless
environment,

M.

[jagan.chowdam · Accepted solution]

You can refer the Miercom Test report for benchmark results on AP performance. 

Please note that these tests are conducted under specific conditions and may not accurately reflect real-world scenarios.

Like @marce1000 said, it all depends on what application, client capabilities and RF environment.

Jagan Chowdam

/**Pls rate useful responses**/

[Leo Laohoo]

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@vinitgori1 wrote:
What is the max client count that is recommended for cisco 9120 and 9130 AP operating on wifi 6 with which I can except a decent performance.

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Get a WiFi site survey done properly because this exact question "how many clients are supported with <MODEL>" gets asked monthly.  The value is easily misused and misinterpreted. 

Get a WiFi site survey done properly so everyone's expectation is done correctly and erases any future animosity.  

[JPavonM · Accepted solution]

There is an easy answer to that question which is that the quality of experience (QoE) of the wireless connection depend on the fair use of every radio channel.

That means that it does not depend on the vendor, AP model, client type or number, traffic type, and most important, not only in your side, as RF medium is a shared medium. Of course you can try to do the best to minimize the side effects of been in a metropolitan area (isolate your office), and in that case, as my colleagues have mentioned, it all depend on multiple factors.

The indicators used to “measure” the connection performance (on a given frequency/channel) are the signal-to-noise ratio (SNR), the channel utilization and the packet retry rate. These KPIs could be addressed with a proper WLAN design and configuration, but there are situations where this simply cannot be predicted as when a non-Wi-Fi interference appears, or more devices than expected connect, or the type of traffic changes, or there are heavy loads of traffic, …

There are many scenarios and use cases to consider:

• Back-office applications only
• Back-office plus heavy downloads (OS patches)
• Back-office plus conferencing/audio
• Back-office plus non-real-time streaming
• Back-office plus non-real-time streaming plus conferencing/audio
• Back-office plus conferencing/audio plus heavy downloads (OS patches)
• Telemetry from IoT sensors (this scenarios is whjere you will get the most clients connected without impacting channel utilization)
• ...

[vinitgori1]

Hello JPavon,
Thank you all for in detail reply.

Could you please share me the channel utilization threshold for 2.4Ghz and 5 Ghz post which users will start facing issues.

[Leo Laohoo]

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@vinitgori1 wrote:
Could you please share me the channel utilization threshold for 2.4Ghz and 5 Ghz post which users will start facing issues.

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That's a loaded question.  There is no "one answer" because it will depend on multiple factors: 

1.  Type of clients, i.  e.  laptops, smartphones/tablets vs barcode scanner vs "IoT" devices vs etc. 

2.  Type of environment, i.  e.  Industrial/Manufacturing vs office vs medical/health sites vs schools

3.  Time of the day

[JPavonM · Accepted solution]

As previously told, this is not an exact science as it does not depend on an unique factor (your side), but QoE dependency on other networks and devices sharing the same RF medium in the vicinity is something to consider.

The next picture I created some time ago can help you with this, but take it with some precaution as thresholds could change depending on the use case and the environment. The thresholds for SNR take into consideration the MCS rates for a given SNR value (greate SNR means greater MCS index which means greater link speed, SNR values below 12 lead to disconnections), and the ones for Signal Strength are based on the observed behaviour for some wireless adapters, but they could be different depending adapter sensitivity and the conditions of the RF medium. The thresholds for Number of Devices are based on EDCA’s Cwmin and CWmax values for BE and BK traffic and observer behaviour, but they can be different depending on the type of clients and traffic, like telemetry data from IoT sensors. The ones for sensitive traffic are based on EDCA’s Cwmin and CWmax values for high priority traffic queues for Voice and Video. The thresholds for Channel Utilization are based in observed behaviour, but they can be different depending on the type of clients and traffic. And the Retry Count it is what it is, a high retry rate impacts performance.