9800-CL download rate half of upload rate

[Clem58]

Hello,

We have a WLC 9800-CL on 17.9.3 code, APs are running in flexconnect.

I'm testing a 9120AXI AP, I have implemented WIFI6 802.11ax and tested on one Dell laptop, It's showing 1633/1922Mbps, DL/UL. Anyway it's limited by the switch port speed where it's connected, as 1Gbps.

However when I do a file test transfer, I can see it's uploading at 100MBps but max at 50MBps for downloading.

Can it be a settings on the WLC ?

Many thanks by advance for your help.

[marce1000]

    - Have a checkup-review of your  WLC  9800-CL   controller configuration with the CLI command : show tech wireless  , have the output analyzed with : https://cway.cisco.com/wireless-config-analyzer
                                         Checkout all advisories!

  M.

[Clem58]

Hi Marce,
Thanks for your help, unfortunately the wireless config analyzer is not working, it stays blank even after uploading the logs archive and running.

[marce1000]

                 >....., it stays blank even after uploading the logs archive and running.
    ?? You only need to  use the procedure as mentioned , remember to use the CLI command show tech wireless (do not use simple show tech for WirelessAnalyzer)

 M.

[Clem58]

I have already did that, I generated the tech log via the GUI downloaded it and droped into the analyzer like I did last times, and after clicking on run, it did not do anything

[marce1000]

                                         >...I generated the tech log via the GUI 
 - That is not the log that WirelessAnalyzer needs it contains to much info (indeed) stick to the CLI command : show tech wireless (only!)

 M.

[Clem58]

Ok thanks Marce but I did "show tech wireless" via the gui and it generated a taz.gz, then I dropped it, I did it several times like this and it worked.
Anyway using the CLI has worked.
Nothing relevant in the report.

[Scott Fella]

Usually you have to extract the tar.gz to actually get the output file.  Anyways, you still having issues and how are the iperf test local on your network?  

[Clem58]

Hi Scott, it's good, if I connect the same laptop on a 1Gb port I have symetrical DL/UL max throughput (~100MBps)

[Clem58]

I mean wired connected on a switch gig port the laptop is at max speed rate on dl and ul, but on wireless dl is at around 50MBps and 100Mbps on ul

[Scott Fella]

You will never get the same ul/dl with wireless.  Mine always changes and is never the same.  Using openspeedtest at my home lab, I get 150 dl / 109 ul.  That changes when I move around in my house or even outside.  Keep in mind that file transfers are also dependent on the disk and hardware.  

[Rich R]

And back to Scott's initial question - how were you testing?

To something on the internet or using iperf server connected to local LAN? (that's how you should be doing it)

Have you checked that the wireless driver is running the latest version?
What is the network adapter model and driver version number?

[Clem58]

I have updated the wireless adapter with the latest version. I'm testing using file transfer on a LAN server, if I copy a file from the computer to the server it's uploading at ~100Mbps, if I download I obtain ~50Mbps, the computer hard drive is a SSD.

But I have also noticed that even if I have put 160Mhz on the DCA config of the RF Profile, the AP keeps staying on 80Mhz.

According to specs the 9120AXI AP should be able to do 160Mhz, so I'm a but surprised.

[Rich R]

When you set that it's the desired channel width, not guaranteed.

Read https://www.cwnp.com/the-wise-article-series-wi-fi-subtleties-explained-channel-bonding/ for background on channel width selection - what you actually get depends on a number of variables.
Also https://www.cwnp.com/the-wise-article-series-wi-fi-subtleties-explained-parameters-that-matter/ on throughput.

[Clem58]

I have tried with 20Mhz and 40Mhz, the AP is correctly changing to this channel width when I modify the profile, but it's not working for 160Mhz, it seems it can support only up to 80Mhz. 

In the specs I can see this AP can run on 160Mhz, so I'm a bit lost :

Could it be because this AP is connected on a 1Gbps port and so does not select 160Mhz because it knows it won't be able to do more ? Would it work if I connect it on a multi-gig port for example ?