WLAN Speed Difference

[Robert Stack]

Good morning,

I am noticing a difference in speed when I connect to one WLAN SSID vs another. I have checked the WLC with no noticable difference in the configuration of one over the other. When I do a Speedtest to the same server I get 20Mbps on the slow WLAN and over 150Mbps on the other. 

Does anyone have any ideas what could cause this? Could there be a bug in the controller software?

Model 5508 Running :7.4.110.0

[Stephen Rodriguez]

Can you share the WLAN configuraitons?

If you are looking to get 802.11n/ac speeds, the WLAN needs to be either open/no encryption or WPA2/AES ( no mixing of AES and TKIP) and WMM has to be allowed.

HTH,

Steve

[Noor Shukri]

Hey Robert,

How did you test the speed? same AP, same client? same location? and above all (same radio band)?

What about QoS configurations on each?  WLC and wired side?

Have you tried to test each SSID interface VLAN speed ?

I don't think its a bug form the controller, kindly share more information about these details.

Cheers,

Nour

[Robert Stack]

How did you test the speed? Working on a unrelated issue I went to Speedtest.net to do a test. It maxed out at 20Mbps. When I switch to the other SSID it maxed out at over 100Mbps

same AP, same client? same location? Yes, I use the same laptop, same login, same location. All i do is switch the network and rerun the test to the same server. I have repeated this test numerous times with the same result. 

and above all (same radio band)? It is switching bands  When on 802.11A speedtest result is the 20Mbps. When on 802.11N speed is over 100Mbps. Where would I find the setting to change to 802.11N on the WLAN that is now running 802.11A?

What about QoS configurations on each? No QoS

  WLC and wired side? No problem with this on wired side.

Have you tried to test each SSID interface VLAN speed ? Nope

[Venkatesh Attuluri]

“Wireless clients are experiencing very slow speed” ,   is a common  problem on a wireless lan environment.

As part of troubleshooting this, we got to take care of

• 1)      Low Signal Strength.
• 2)      Low SNR.
• 3)      Insufficient Data rate.
• 4)      Packet Drop.
• 5)      Interference.
• 6)      Client Driver problem.
• 7)      QoS related problem.
• 8)      Problem with Roaming.
• 9)      OR  Any configuration related problem.

During the course of troubleshooting, we do need a way to test the throughput, as and when we make any changes.

IPERF comes as a very handy tool. This can easily tell us the speed of data transfer.

Here are the details for the IPERF test.

https://supportforums.cisco.com/document/12068771/iperf-test-measuring-throughputspeed-wlan-client