Wireless 802.11ac 5Ghz Low Bandwidth

[Helmi Muzammil]

Hi All,

I have Cisco Wireless Infrastructure as below :

Wireless Controller : Cisco WLC 5520

Cisco WLC Version : 8.10.130.0
Cisco AP : AIR-AP2802I-F-K9
Cisco AP Mode : Local Switching

I found strange issue. when client connect to 802.11ac using 5ghz the speed is limited under 10Mbps. I have implemented the Data Rates and RRM as per cisco best practice but the problem persist. i have setted up the clean air and there are no interference,

But when i try to force the channel bandwidth to 20Mhz. the 802.11ac 5ghz speed will increase more than 100Mbps.

Could you please help me analyze why this problem occur? why if we use auto channel bandwidth like 40Mhz and 80Mhz the wireless bandwidth will drop to below 10Mbps?

[Leo Laohoo]

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@Helmi Muzammil wrote:

when client connect to 802.11ac using 5ghz the speed is limited under 10Mbps.

But when i try to force the channel bandwidth to 20Mhz. the 802.11ac 5ghz speed will increase more than 100Mbps.

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This only proves the wireless client does not support 80- or 160 Mhz.  

What is the model of the wireless NIC and what is the exact wireless NIC driver being used?

[Helmi Muzammil]

Hi @Leo Laohoo 

Thanks for the reply, it's happen to all of users ( android, iphone, windows (hp, dell, asus) ).

[Leo Laohoo]

Are you sure the wireless clients are actually connected to 5.0 Ghz (and not 2.4 Ghz) when observing 10 Mbps? 

Re-enable 80- or 160 Mhz channel bond and post the complete output to the following WLC commands: 

show ap auto-rf 802.11a <AP NAME>
show ap auto-rf 802.11-abgn <AP NAME>
grep include <AP NAME> "show advanced 802.11a txpower"
grep include <AP NAME> "show advanced 802.11-abgn txpower"

Ok, let's start with that.