Indication loss when multiple peripheral devices are connected

RE: Indication loss when multiple peripheral devices are connected

Jithin A — Tue, 10 Dec 2024 09:55:11 GMT

Hi Susheel,

Sorry for the late reply. I was working on other high priority project.

The above suggestion worked well for us. We now changed the architecture such that the central device monitors all its connected peripherals subscription param without overwriting.

RE: Indication loss when multiple peripheral devices are connected

Susheel Nuguru — Tue, 19 Nov 2024 15:25:58 GMT

Unfortunately we do not have an example to directly show that.

RE: Indication loss when multiple peripheral devices are connected

Jithin A — Tue, 19 Nov 2024 06:52:00 GMT

Hi Susheel,

Thank you for the response, will review the subscription handle as you said and update.

Is there any example reference I can refer to which support multi device subscription and handling, if so, can you please share the link or document which can help me for even better understanding.

RE: Indication loss when multiple peripheral devices are connected

Susheel Nuguru — Sun, 17 Nov 2024 11:03:51 GMT

There seems to be a likely issue related to the management of CCCD (Client Characteristic Configuration Descriptor) settings or the BLE stack's event handling in your application.

Looked at your code briefly, I think there is a flaw in your connection management as CCCD management is not done per connection.

Initial connection, First device connects and enables indications through a CCCD write.
The second device connects. If the application overwrites the CCCD or doesn't enable it for the first device, the first device is unsubscribed.
As a result, bt_gatt_indicate(NULL, &ind_params) now sends indications only to the second device.
The central receives indications only from the most recently connected device because it is the only one with an enabled CCCD.
CCCD writes are not handled per connection.
The application may be overwriting CCCD settings globally or failing to re-enable them for all active connections.
Using NULL as the connection handle for bt_gatt_indicate() sends indications to all subscribed devices. If only the most recent device has its CCCD enabled, only it will receive indications.