Question about 2.4Ghz and 5Ghz

[carl_townshend]

Hi Guys

I have a quick question around how clients decide which band to connect to normally, for example a laptop which does not have prefer 5Ghz enabled and no band steering on the access points, would the client generally pick the 2.4Ghz band as this is normally seen as a stronger signal ?

cheers

[Kasun Bandara]

this thread is really helpful and check that

https://community.cisco.com/t5/wireless/clients-seem-to-prefer-2-4ghz-instead-of-5ghz/td-p/3849958

[balaji.bandi]

Its all depends on what client WLAN you using. and drivers and chipset.

you can configure on the end device, what frequency to connect. latest prefer 5GHz over 2.4ghz

Some legacy clients still need to 2.4Ghz to connect.

some example clients here :

https://documentation.meraki.com/MR/Other_Topics/Configuring_Wireless_Band_Preference_on_Client_Devices

[Arshad Safrulla]

Even though you have band steering enabled, client has the ultimate authority to take the decision to connect to which AP on which band. Concept is simple, client uses it WLAN NIC programming to decide what AP has the best connectivity (mostly client's make bad and wrong decisions due to drivers). As you mentioned above 5GHz preferred configured under the Driver Advanced option will steer the client to 5GHz, but it some times works some times doesn't. Also I do not think Intel or any driver manufacturer has reveled what parameters they look at when the client is steered to 5GHz from 2.4GHz or how the roaming decisions are taken. The best you can do is assume that the client will work properly and make best WLAN design decisions.

[Leo Laohoo]

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@carl_townshend wrote:

would the client generally pick the 2.4Ghz band as this is normally seen as a stronger signal ?

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@carl_townshend, 

NOTE:  I am going to presume the wireless NIC driver was never updated. 

From past experiences and past history in this forum, yes.  By default, the wireless NIC will pick 2.4 Ghz not because of a "stronger signal" because this is how they were coded.  When Intel released the first two generation of dual-band NICs "for commercial" use (low-end installation), the developers had in mind that 2.4 Ghz was going to be "mainstream" for residential use.  No one envisaged 5.0 Ghz to be found in homes.  This is one of the reasons why 2.4 Ghz were the "default" behavior.  

Fast forward to present day, if I get calls of "WiFi not working" (or something to those words), the Level 1 people know that my first  two questions would be "what is the model of the NIC" and "what is the firmware of the NIC".  They also know that if they do not update the wireless NIC firmware FIRST (before calling me), the next thing they will hear is me slamming down the phone.