How is the white list size defined in Bluetooth LE?

[Bruno Hars]

Neither in BLE core specification nor in your documentation I found a hint, how the size of white list is defined and what the limits are.

At the Link msdn.microsoft.com/.../jj134352.aspx I found following statement: "Bluetooth controllers must support a minimum LE white list size of 25 entries." The limit seems to be chip-specific. But is that statement true?

Questions:

• Is there a minimum size defined for BLE white list?
• What are the white list size limits (upper / lower) at Nordic Chips?
• Is the white list size configurable or fixed?
• May Centrals and Peripherals use the full size of white list?

Thanks for reply

[Ole Morten]

The S110 supports a whitelist of up to 8 addresses and 8 IRKs. There is no minimum size, and in fact, when you want to bond to a new device, you need to make sure that you don't use a whitelist at all.

You can't change the maximum size of the whitelist, but you are free to fill as many items as you'd want to, i.e. from 0 to 8.

May I ask what you actually try to achieve?

[Bruno Hars]

Thanks for your information.

I am clarifying a use case with fixed 25 or 50 peripherals bonded with fixed 1...n centrals. If once configured, there is no need to bond to new devices. The connections must be secured against unauthorized access. Now with S110 I can bond every peripheral with up to 8 centrals. Do you see any problems for that scenario?

Can you tell me, is the size of the whitelist limited by software stack or by hardware?

[Ole Morten]

This should be possible to do. The whitelist limit is a hardware limitation, so it won't change any time soon.