Catalyst 9800-CL + Aironet 3702i Performance

[UltraSPARC]

Hello!

I've been experimenting around with the newer 9800-CL vWLC appliance. I have a sole 3702i connected to it. I cannot for the life of me figure out how to get it to exceed 300Mbps (iperf3 and speedtest.net). I've tested both on a Windows laptop with an Intel 802.11ax card and an iPhone 11 Pro Max. There seems to be some wall that I'm hitting. Any suggestions would be GREATLY appreciated!! Config attached.

[Rasika Nayanajith]

Pls provide below output from your C9800

sh ap dot11 5ghz summary

show wireless client summary

show wireless client mac-address <client_mac_addr> detail | in dB|Rate

HTH

Rasika

[UltraSPARC]

Hi Rasika! First of all, thank you for taking the time to help me. I hope you're staying safe right now! I wanted to add, that I also put a second 3702i AP on the network too. I wanted to see if maybe I had a bad AP... It did not change anything... Although I do have a number of devices connected to it (mostly smart switches), the only three devices connected to the AP's at 5GHz are the iPhone, Apple TV, and Razer laptop...

Here are my results:

sh ap dot11 5ghz summary
Wed Apr 29 2020 13:54:36 GMT-0400 (Eastern Daylight Time)
===================================================================================
#sh ap dot11 5ghz summary
AP Name Mac Address Slot Admin State Oper State Width Txpwr Channel
---------------------------------------------------------------------------------------------------------------------------------
second_floor d8b1.900d.af50 1 Enabled Up 80 *1/6 (17 dBm) (100,104,108,112)*
basement f4cf.e2ae.9df0 1 Enabled Up 80 *1/6 (17 dBm) (64,60,52,56)*

show wireless client summary
Wed Apr 29 2020 13:55:05 GMT-0400 (Eastern Daylight Time)
===================================================================================
#show wireless client summary
Number of Clients: 16
MAC Address AP Name Type ID State Protocol Method Role
-------------------------------------------------------------------------------------------------------------------------
00d0.2df1.df03 second_floor WLAN 1 Run 11n(2.4) None Local
2462.ab05.5e7f second_floor WLAN 1 Run 11n(2.4) None Local
2462.ab05.762d second_floor WLAN 1 Run 11n(2.4) None Local
2462.ab05.d96f basement WLAN 1 Run 11n(2.4) None Local
2cf4.32a4.af1e second_floor WLAN 1 Run 11n(2.4) None Local

3800.25a9.7059 second_floor WLAN 1 Run 11n(5) None Local
4c11.ae12.c68e second_floor WLAN 1 Run 11n(2.4) None Local
5002.9141.bf1e basement WLAN 1 Run 11n(2.4) None Local
5032.37c5.d1e7 second_floor WLAN 1 Run 11n(5) None Local
5caa.fd0c.4ee0 second_floor WLAN 1 Run 11b None Local
Number of Excluded Clients: 0
Number of Clients: 16
MAC Address AP Name Type ID State Protocol Method Role
-------------------------------------------------------------------------------------------------------------------------

787b.8a8e.df1b basement WLAN 1 Run 11n(2.4) None Local
8c86.1e42.c55b second_floor WLAN 1 Run 11n(5) None Local
c44f.3384.d456 second_floor WLAN 1 Run 11n(2.4) None Local
c44f.3384.d574 basement WLAN 1 Run 11n(2.4) None Local
c44f.3385.015e basement WLAN 1 Run 11n(2.4) None Local
d0d2.b09c.f433 basement WLAN 1 Run 11n(2.4) None Local
dc4f.22b4.1253 basement WLAN 1 Run 11n(2.4) None Local
Number of Excluded Clients: 0

show wireless client mac-address 8c86.1e42.c55b detail | in dB|Rate
iPhone:
Wed Apr 29 2020 13:56:28 GMT-0400 (Eastern Daylight Time)
===================================================================================
#show wireless client mac-address 8c86.1e42.c55b detail | in dB|Rate
Current Rate : m9 ss2
Radio Signal Strength Indicator : -44 dBm
Signal to Noise Ratio : 46 dB
AND
Razer Blade 15 /w Intel Wi-Fi 6 AX200 160MHz card
Wed Apr 29 2020 13:58:39 GMT-0400 (Eastern Daylight Time)
===================================================================================
#show wireless client mac-address 3800.25a9.7059 detail | in dB|Rate
Current Rate : m9 ss2
Radio Signal Strength Indicator : -50 dBm
Signal to Noise Ratio : 43 dB

[Rasika Nayanajith]

Thanks for the output detail. APs are on clean channels with 80MHz and clients are getting good RSSI/SNR.

It is strange clients show 11n, that should be 11ac. (here is for iPhone & laptop). 

8c86.1e42.c55b second_floor WLAN 1 Run 11n(5) None Local

3800.25a9.7059 second_floor WLAN 1 Run 11n(5) None Local

Look at below table values (yellow for 11n & blue for 11ac data rates that you can expect based on MCS, channel width, spatial stream, guard interval). As you clients say, m9 ss2, assuming they are connected with 802.11ac (VHT) their data rates should be either 780 or 866.7Mpbs (note that this is not throughput). If you are getting 300Mbps throughput, then that would be normal in those circumstances. Due to half-duplex nature, you won't see 866.7 as client throughput, will be less than 50% of that rate as the client cannot tx/rx simultaneously, then certain % of airtime gone for management & control traffic & other overheads.

http://mcsindex.com/ 

If you want to test best case here is what I suggest. Create a new SSID only on 5GHz. Advertise it on those 2 APs and test your laptop first (no iPhone or AppleTV) & see what upload/download you get. Then do the same test for the other two clients individually. Then you can put 3 clients to SSID and see if you can beat previous values, you will see client performance is below compared to test results you got when you do it individually.

To see that 11n is a cosmetic issue, I would like to check that all MCS rates (11ac/11ax related are enabled) on your 5GHz network. Pls share below output as well

show ap dot11 5ghz network

HTH

Rasika

**** Pls rate all useful responses ***

[Scott Fella]

Just to add, the 3702 is not ax only ac. So what you are seeing isn’t bad to be honest. If your Windows laptop show connection rate for example 600mbps, your theoretical max would be half of that and the more devices transmitting on the same ap and or channel, the lower the throughput.

[UltraSPARC]

Hi Scott! I completely agree and understand that these are only AC AP's. I was honestly looking for something in the 500-600Mbps range, as you've mentioned, you normally take the advertised speed and dived by two. 300Mbps seemed low to me, but I could be wrong! Rasika wanted some additional info above so let's see if he sees anything I'm missing? Thank you so much for your reply!

[Scott Fella]

I know... did you read what Rasika posted? He shows the data rate which lines up with your mcs rates. He also mentioned that you would only be able to achieve half of that number. So let’s say you connection rate is 800mbps, the most you would get theoretically would be 400mbps at most. You will not be able to achieve the 500-600.