Wrong lowest supported rates: code 8.5.151.0

[SS87824]

Hi Folks,

My lowest supported rates on 5GHz in global configuration is 36 and I don't have RF profiles configured in groups, but for clients I see 6.0 in supported rates.

WMM Support...................................... Enabled
APSD ACs....................................... BK BE VI VO
Current Rate..................................... m8 ss2
Supported Rates.................................. 6.0,36.0,48.0,54.0
Mobility State................................... Local

Same has been reported in the below post.

https://community.cisco.com/t5/wireless-and-mobility/mcs-rate-that-being-used-by-clients/m-p/3403742/highlight/true#M100239

If I go to the AP and check #sho controllers dot11Radio 1, there is traffic on 6.0

show per rate stats:

RATE 6.0
Rx Packets: 713864 / 30 Tx Packets: 3544 / 0
Rx Bytes: 345693 / 0 Tx Bytes: 283520 / 0
RTS Retries: 0 / 0 Data Retries: 0 / 0

RATE 36.0
Rx Packets: 9668 / 1 Tx Packets: 7471 / 0
Rx Bytes: 4092482 / 1504 Tx Bytes: 3084468 / 0
RTS Retries: 0 / 0 Data Retries: 18668 / 0

RATE 48.0
Rx Packets: 4277 / 0 Tx Packets: 81 / 0
Rx Bytes: 1921559 / 0 Tx Bytes: 27132 / 0
RTS Retries: 0 / 0 Data Retries: 0 / 0

RATE 54.0
Rx Packets: 10947 / 1 Tx Packets: 3 / 0
Rx Bytes: 4063012 / 1504 Tx Bytes: 1026 / 0
RTS Retries: 0 / 0 Data Retries: 0 / 0

[Scott Fella]

You should open a TAC case. I haven’t seen that in any of my installs. What controller and AP’s? Is this on various client devices?

[SS87824]

WLC: AIR-CT5520-K9
AP: AIR-AP3802E-F-K9

This is on multiple devices and the device which are showing this has huge difference in speed in what is in dashboard and actual from client machine.

For example: WLC Dashboard is showing 780Mbps, 80MHz, 2SS for 1 client. But a quick netsh wlan show interface  on same client machine shows the speed as 173Mbps.

I found one device which did not show 6.0 as supported rates and the speed that client received is 433 Mbps. Interestingly for this client the speed is same in both WLC and in actual machine.

In below debug logs it looks like client is associating with rate 6.0

*apfMsConnTask_5: Jan 17 13:25:09.939: [PA] <redacted MAC> STA - rates (4): 12 200 96 108 0 0 0 0 0 0 0 0 0 0 0 0
*apfMsConnTask_5: Jan 17 13:25:09.939: [PA] <redacted MAC> suppRates statusCode is 0 and gotSuppRatesElement is 1

Unfortunately support has expired and it will take some time to renew it. So TAC is not an option.

[Scott Fella]

Well from my experience, the RF dashboard doesn’t refresh right away and windows netsh aslo doesn’t refresh right away and at times it seems to hang, drivers fix or break that). Now what I end up doing is still looking at the cli for the client device to see what it’s connected to and I will also do the netsh and if it’s close, I don’t really care.

As far as the 6mbps supported rate, TAC will probably say to upgrade or open a bug for that. I don’t think without a different firmware that your issue will go away. There is a newer code for 8.5 and you can always try that and see if that fixes it or not, but if not, well then TAC would file a bug and you would have to wait for a fix.