Hi We have C9800 WLC. If we just setup ssid like ABC, we can see the ssid via end device. I would like to know if this ssid ABC is 2.4G, 5g or both? How can end device choose 2.4G or 5G depends end device NIC configuration? or something else? Thank you
By default when you set up an SSID on the 9800 , assuming 2.4 and 5ghz are both enabled globally for the Ap , the SSID by default supports all radios, you should see this when you click on the WLAN config on the general page in the "radio policy" section . You can change the radio to only be 5GHz for example by setting it to "802.11a" or whatever you would like it to be depending on your business use case
As far as client NIC config , most clients natively prefer 2.4 initially. However , if they support both 2.4 and 5GHz, they can roam to a 5GHz radio if that is available on the AP.
Hope this helps !
>.... if we choose some APs emit 2.4G only and other APs emit 5G only?
- I would strongly advice against that taking into account clients that can only do 2.4Ghz (e.g.), also while 2.4Ghz has more 'contenders' is passes easily through obstructions. All of that being somewhat 'fluid arguments' , the best solution for best coverage is to have site survey done. Your action will introduce all sorts of roaming problems too , take care!
Some client NICs allow you to configure a preference for 2.4 or 5 or even turn either off - entirely dependent on the device driver and what options it exposes to the OS.
In Windows look at the Advanced properties tab for the NIC in Device Manager.
Choosing which band to connect is purely client decision, client will decide this based on how the WLAN driver is programmed. You have the option of configuring this in certain devices and cards such as Windows (as below) and Android.
From controller side you can influence the clients to go to 5GHz by you can have below options enabling Client steering to 5GHz (Band select). This will modify the beaconing process to push the clients towards 5Ghz.
Other option is to have separate SSID's for 2.4 and 5Ghz bands (not recommended as you have to manage 2 SSID's).
If you want to disable 2.4GHz per SSID that is also possible by Cisco WLC configuration. CIsco provides granular options such as disabling 2.4 radios per AP, per SSID, for all the AP's in WLC etc. Depending ont he platform and code you are running please refer to the configuration guidelines.