Device discovery when bonded devices re-connect

RE: Device discovery when bonded devices re-connect

tesc — Wed, 08 Jul 2026 21:11:48 GMT

Hi,

The layout of the GATT table does not change on reset, provided the application is still the same.

For completeness: For the GATT table to change, you need to either perform a firmware upgrade, or deliberately initiate a different set of services and characteristics (or in a different order.) Please note that for any change of the GATT table (either by firmware upgrade or otherwise) you should make sure to use the Service Changed characteristic to communicate the change, or use a different BLE address for the device.

Regards,
Terje

RE: Device discovery when bonded devices re-connect

Phil — Tue, 07 Jul 2026 00:13:30 GMT

Terje,

Thanks for your reply. This makes sense and is useful as device discovery on every re-connection takes time.
We want the bonded devices to connect quickly, upload some data to the Central then disconnect.

If the peripheral resets, either by software reset or power cycle, does the GATT table and all the attribute handles stay the same?

RE: Device discovery when bonded devices re-connect

tesc — Mon, 06 Jul 2026 18:05:31 GMT

Hi,

The central generally does not need to perform database discovery again on a bonded device, no. By default, peripherals in nRF Connect SDK has the Service Changed characteristic, which is used for indicating whether the GATT table has changed or not. This means the central may choose to cache the GATT table layout, thereby not having to perform Database Discovery on reconnection. Nevertheless, it all depends on the central, whether the central does the caching or not. Some centrals do, others do not.

Regards,
Terje