Slow wireless speeds (5Ghz, N, 26MB??)

[Tom_Taylor1]

I've been having intermittent issues that naturally aren't here when ever I log a case with GTAC so was wondering if anyone else has seen something similar.

Our clients here often complain about slow wireless speeds and I'm really having a hard time tracking it down, today though I did notice that one of the clients had "full bars", connected at 5Ghz but the TX rate was only 26Mb?

The network itself isn't anything fancy.

Topology is Bridged locally at AP (Running a tagged VLAN)
CoS is turned off
WPA-PSK v2
No Authentication
WMM turned on for QoS

Anyone seen this before?

Here is another client literally right next to this one

[Gareth_Mitchell]

Tom

The RSSI is very low on the client with the low data rate and it is on a different channel to the client with the higher data rate.

It's hard to tell you exactly why that is, but I imagine the poor performing device is associated to a distant AP (observe the BSSID is different between the 2)

In the controller inventory report you can check which BSSID that matches or check the AP client reports to see which this AP is and map that to your wlan layout.

Typical methods to resolve this kind of sticky client problem are covered in this article: https://gtacknowledge.extremenetworks.com/articles/Solution/Issues-with-clients-staying-with-an-Acce...

-Gareth

[Tom_Taylor1]

Thanks for this Gareth, agreed it does sound like this might be the issue. I've applied what's suggested and we'll see how it goes

[Jeremy_Gibbs]

Look at the RSSI / Noise that client is dealing with. I bet if you were to look, there is a lot of retransmits, which further delays wireless transmissions. What do you have your MBR set to for 5 Ghz? Is it at least 12 Mbps?

What I am thinking is happening is, you have some sticky clients connecting to the 5ghz radio on an AP that is much further away. I would check the MBR settings first, and if it's at 12 Mbps and you have ok coverage, you could start playing with probe suppression with force dissociation. I have mine set for -75 dB (so I think the AP will boot the client at -78 dB).

[Tom_Taylor1]

Thanks for this! Although can I ask a stupid question which is where to check the MBR settings? Wifi is still a bit of a dark art to me.

*EDIT - Found it. Thanks for this. Does quite sound like this might be the source

[Ronald_Dvorak]

Hi Tom,

I've one customer that also reports slow thruput but I wasn't onsite yet to take a closer look.

Could you tell us what AP model is used and the software version and the client type/model.
Also what type of app is used for the output in the screenshots.

The first client show a very low signal with result in "only" 10dB SNR - as you'd see on the second client the signal is far better which result in a higher MCS = rate.