Ble Mesh PB-GATT - how is the connection established?

[Mahendra Tailor]

Hi

An unprovisioned device will advertise a beacon and the spec says that it shall be advertised with non-connectable and non-scannable undirected advertising events

The provisioning protocol can use PB-ADV or PB-GATT. The latter involves making a connection. The Mesh Profile specification even goes as far as saying that the connection interval is recommended to be between 250 and 1000 milliseconds.

Question ::: if the unprovisioned beacon is not connectable how does a provisioner even initiate a connection?

Is it the case that there will be additional adverts that the unprovisioned device will send to invite connections? If so that is inefficient.

If the spec allows for PB-GATT then I would have thought that the beacon would be connectable to give the provisoner the choice of using PB-ADV or PB-GATT

Look forward to hearing from you and thank you in advance

[Hung Bui]

Hi Mahendra,

From my understanding, PB-GATT use Proxy protocol (GATT bearer) so a BLE connection need to be established. The unprovisioned device needs to send normal connectable advertising packet. And the provisioner should established the connection like a normal BLE connection.

After that they can start provisioning via PB-GATT.

Is it the case that there will be additional adverts that the unprovisioned device will send to invite connections? =>Correct if it wants to be provisioned by both options.

If the beacon do PB-ADV it has to be nonconnectable non-scannable as stated in the spec.

[Mahendra Tailor]

So the implication behind what you are saying is ...

Provisioner sees the provisioning beacon. It wants to use PB-GATT, so it will initiate a connection for a set amount of time using the mac address in that beacon. The provisonee knows it wants to accept PB-GATT provisioning so it interleaves normal adverts which will allow that initiation to work and result in a connection.

I now understand that and I wish the BT SIG had just placed a note to this effect :-)

Kind regards

[johnny]

BT SIG Management of Devices in a Bluetooth Mesh Network blog.bluetooth.com/management-of-devices-bluetooth-mesh-network