High latency for wireless clients

[AxL1971]

This is one of them open questions and probably not a simple answer

AP's are MR56 and noticed alot of users complaing about wireless performance.

Looking at the clients performance on the dashbooard the latency is around 700 ms, however the number of clients connected to the access point is about 30 which to me isnt that high and wouldnt expect high latency.

I cross referenced the high latency for the device to the AP and no high latency recorded on the AP at the time the client recorded an high latency.

I also checked for channel collision and the other AP's on the same floor are using different channel. We only broadcast the SSID on 5 Ghz

What is common reasons for high latency 

[Inderdeep]

You should check this one 

https://documentation.meraki.com/Architectures_and_Best_Practices/Cisco_Meraki_Best_Practice_Design/... 

[alemabrahao]

30 connected clients, which is a considerable number depending on the type of traffic they are consuming, could be one of the explanations.

Take a look at the troubleshooting you can do.

https://documentation.meraki.com/MR/Wireless_Troubleshooting/Wireless_Issue_Resolution_Guide

https://documentation.meraki.com/MR/Wi-Fi_Basics_and_Best_Practices/Tools_for_Troubleshooting_Poor_W...

[michalc]

Interesting issue you have there. I have couple of questions that might help you with finding the solution:

• How many SSIDs are configured on the AP's?
• Do all of the clients experience the same issue on all of the SSIDs? 
• Is there any common denominator between the clients? (perhaps same laptop with same wireless adapter driver)
• Is there a Mac device that experience the issue? It would be great to check the RSSI, Noise, TX Rate and MCS index. This could be done pressing the "Command" + WiFi symbol on Mac.
• Do one of the clients use an excessive bandwith compared to others?
  • Have you tried setting up a bandwith limit per client on the SSID?
• Do you have default traffic shaping rules applied on the SSID?
• Do you see an excessive broadcast or multicast traffic while the issue occurs?
• Are your AP's up to date? 

[AxL1971]

answer you your questions

• How many SSIDs are configured on the AP's? 3 SSID - 1 Corporate SSID on 5Ghz and 2 SSID's on 2.4 Ghz - all laptops with latency issue connect to the 5Ghz band
• Do all of the clients experience the same issue on all of the SSIDs? - so far only 4 people have mentioned it, so can assume others may experience some issue but not said anything 
• Is there any common denominator between the clients? (perhaps same laptop with same wireless adapter driver) Laptops are Thinkpads - around 2 years old either running the Intel AX201 or AX211 wireless chipset
• Is there a Mac device that experience the issue? It would be great to check the RSSI, Noise, TX Rate and MCS index. This could be done pressing the "Command" + WiFi symbol on Mac. - No Mac devices
• Do one of the clients use an excessive bandwith compared to others? - not that I am aware of, majority of traffic would be outlook and Teams
  • Have you tried setting up a bandwith limit per client on the SSID? - no
• Do you have default traffic shaping rules applied on the SSID? - yes default traffic shaping
• Do you see an excessive broadcast or multicast traffic while the issue occurs? - not that I am aware of, issue mostly occur in Teams call
• Are your AP's up to date?  AP running firmware that we applied late last year, I am aware a new firmware was released this month so plan on applying to all AP's

[PhilipDAth]

Have you set the minimum bitrate on the 5Ghz band to 12Mb/s or higher?

[AxL1971]

currently set to minimum bitrate 18 Mb/s

[PhilipDAth]

Does Wireless Health report anything interesting?

https://documentation.meraki.com/General_Administration/Cross-Platform_Content/Meraki_Health_Overvie...

Does the issue exist when there are less people on the WiFi?  Aka, does the issue always exist, or only when a lot of people are using it?

[AxL1971]

Health status for the AP where users have high latency is good, this is the confusing bit to me, latency from AP is good where as latency from client is high.

I suspect issue is probably due to number of devices connected, however in my opinion 30 people connected to an AP isnt classed as high.

[PhilipDAth]

>latency from client is high

This smells like client power savings.  What kind of device is this?
Does it happen when the client is plugged into the mains?

If this is affecting Windows hosts you can usually disable WiFi power savings with these commands:

powercfg /SETDCVALUEINDEX SCHEME_CURRENT 19cbb8fa-5279-450e-9fac-8a3d5fedd0c1 12bbebe6-58d6-4636-95bb-3217ef867c1a 0
powercfg /SETACVALUEINDEX SCHEME_CURRENT 19cbb8fa-5279-450e-9fac-8a3d5fedd0c1 12bbebe6-58d6-4636-95bb-3217ef867c1a 0

[AxL1971]

These are all Thinkpad laptops running Windows 10/11.

Not sure if they are plugged in not. I will need to ask the user.

[AxL1971]

This is what confused me, this is one of the client with the high latency issue - the peak is around 700 ms 2.35 pm today

Now for the AP the client was connected to, the latency around the same time is much lower. At 2.25pm today the latency on the AP was 6ms

Unless I am misreading the graphs on the dashboard, but I would expect the latency to be same/similair on the dashboard for AP and client