Band Select

[hs08]

In wireless environment should we enable the 'Band Select' or not? Based on this document enabling the Band Select will make 5Ghz will more attractive so the client will try to join to the 5Ghz first.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/802-11-parameters-and-band-selection.html#:~:text=Band%20select%20works%20by%20regulating,show%20dot11%20band%2Dselect%20command.

But if I enabled this, then if I go to the best practice i got below recommendation. Are this recommendation say that we must disable the band select?

[marce1000]

  - Ref : https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/technical-reference/c9800-best-practices.html#Bandselect
   >...
   >Do not use band select if you will deploy voice or video services (any interactive traffic), as it may impair roaming performance on some client types.

  M.

[Saikat Nandy]

It's always a good option to enable band select. But world is moving and there are quite a lot of customers who prefers to disable 2.4 completely. If you disable 2.4 then this option is null n void.

[hs08]

so based on Cisco Best Practice in the controller should we disable the band select?

[Scott Fella]

@hs08 This is not a best practice per say, because it's a feature and this features depends on your environment.  Like what others have mentioned, you have different devices that others would have in their environment, so you need to know if enabling this has any bad affect on clients, you must also look at your 2.4GHz and 5GHz client distribution.  If you already have majority of clients connected at 5GHz, then maybe this feature isn't going to help much.  Some device also have problems with band select enable, which you need to test.  There are also setting in band select that can be adjusted, which again, you need to test.  It's easy to say, its a good feature to enable, then all of a sudden you have devices that can't connect or have issues when roaming or just initially connecting to the network.

The most stable wireless environment is the most basic. I like features, but you never know if that will cause harm in your environment, when there are upgrades, or client side upgrades.

[Saikat Nandy · Accepted solution]

One thing you need to understand that Cisco's best practise might not be best practise for your 'environment'. Cisco Best Practise is a generic recommendation. Also we need to understand that what sorts of configuration or feature we are talking here. This feature is specific to clients. Now it depends how much control do you have on your clients, whether those are latest or legacy, what sorts of SSID is this etc.

Few years back during AireOS era, we used to suggest people to enable band select (the restriction of voice/video was still there). Now that recommendation has changed as the endpoints have evolved. If you have a mixed environment with legacy (dual band capable but connect to 2.4Ghz quite often) as well as latest clients, then you can enable band select. If you see the devices are connecting to 5Ghz, then you don't need band select. In fact you can just keep the SSID on 5Ghz. So it's all about your environment, client type.

[eglinsky2012]

In my higher education environment, I’d say 95% of our provided and our BYOD mobile devices connect at 5 GHz. Most of those on 2.4 are IOT devices, or are in an area where 5 GHz coverage is lacking. It seems the devices do a good job deciding for themselves to connect a 5 GHz, so I don’t see the need to use band select, especially since it introduces the roaming issues as mentioned. Your mileage may vary.
 

[Karsten Iwen]

I would address this problem differently: 

1) If this is a corporate SSID, just don't enable it for 2.4 GHz. We don't want an interband roaming between 5 and 2.4.

2) If it is an SSID for IoT-like devices, either only use 2.4 or use both 2.4 and 5 GHz and don't care which band is used.

In both cases, you can keep Band Select deselected because it doesn't matter.,