What is Connection bonding ?

RE: What is Connection bonding ?

bjorn-spockeli — Fri, 15 Jul 2016 09:28:00 GMT

If you want the MCP app to reconnect automatically, then you have to modify the MAC address in the bootloader as well.

RE: What is Connection bonding ?

ToTo — Thu, 14 Jul 2016 08:47:21 GMT

No. In the app use a MAC @ totally different. I take the one given by Nordic and i change the 2 first bytes to FF. And on the bootloader , i keep the one given by Nordic.

RE: What is Connection bonding ?

bjorn-spockeli — Thu, 14 Jul 2016 07:52:35 GMT

Is it the bootloader MAC adress equal to the application MAC address + 1?

RE: What is Connection bonding ?

ToTo — Thu, 14 Jul 2016 07:18:11 GMT

Ok thnaks . the other question you didn't reply : I changed the bluetooth MAC address in the app where i'll add the DFU service, so when after jumping to the bootloader, there is another MAC address. Dose it bother ?

RE: What is Connection bonding ?

bjorn-spockeli — Wed, 13 Jul 2016 11:39:08 GMT

This is already implemented in the SDK, please take a look at the ble_app_hrs example with DFU support, you'll find it in /examples/ble_peripheral/PCA100xx/s13x_with_dfu.

RE: What is Connection bonding ?

ToTo — Wed, 13 Jul 2016 10:43:55 GMT

I want an app that perform DFU service ( i choose DFU service on the app when connecting to it with MCP then automatically the app jump to bootloader and MCP reconnect automatically to continue DFU) , can you help me ?

RE: What is Connection bonding ?

ToTo — Wed, 13 Jul 2016 09:54:26 GMT

Ok, just one other question to be sure : I'm using an mac address different in the app than the one of the bootloader, it doesn't bother no ? I understand that the mac address will be shared is the one of the dongle linked to the MCP . Am i right ?

RE: What is Connection bonding ?

bjorn-spockeli — Wed, 13 Jul 2016 08:24:39 GMT

Hi Toto,

After you've connected to a device you may pair with it in order to encrypt the connection. Pairing is essentially the exchange of temporary encryption keys, referred to as Short Term Keys(STKs).

After you have paired, you have the optional choice of bonding with the device, which is the exchange of Long Term Keys (LTKs) which can be used to re-encrypt the connection. The bonding information( the LTK and the device address) is stored in flash, so if you disconnect from the device and reconnect after some time, the device will use the LTK to re-encrypt the link so that you do not have to go through the paring and bonding process again.

The application will share the bonding information with the bootloader (saves in RAM), resets into bootloader and then the bootloader uses this to automatically reconnect using whitelist advertising. However, the device will reconnect even though you do not bond, then only the device address will be shared and it will reconnect using directed advertisment. This is described on this Infocenter page.

I recommend taking a look at our Glucose Application example if you want to see how bonding is done.

Bjørn