Does PAwR and AUX_CONNECT_REQ need Resolvable Private Addresses (RPA)?

[cegerer]

I'm a bit confused about configuration necessary for PAwR where a connection is initiated with AUX_CONNECT_REQ as in examples periodic_adv_conn/periodic_sync_conn. If I disable CONFIG_BT_PRIVACY and CONFIG_BT_SMP, the connection creation times out. Also changing the extended advertising configuration to advertise with the device's identity address does not prevent the timeout. Are there other configuration or settings needed to make the example work without CONFIG_BT_PRIVACY disabled? And if not could you point to the part in the Bluetooth spec where this requirement comes from?

I'm aware of compromising privacy when disabling it, but I couldn't find something in the Bluetooth spec demanding BT privacy enabled for PAwR and connection establishment.

[Hieu]

Hi cegerer,

When you disable CONFIG_BT_PRIVACY and CONFIG_BT_SMP, did you do so on both devices or just one? If just one, which one?

Hieu

[cegerer]

Hi Hieu,

I tested now all combinations again:

• OFF for both devices (Adv/Scanner) does not work
• OFF for Adv, ON for Scanner works (also works when using option BT_LE_ADV_OPT_USE_IDENTITY for advertising)
• ON for Adv, OFF for Scanner does not work

Could you please explain why it only works if scanning device uses RPA?

Thanks,

Christian

[Hieu]

Hi Christian,

I need to consult with our Host team a little. I will come back with details as soon as I have them.

Best regards,

Hieu

[Hieu]

Hi Christian,

My apology for the long wait. I needed to wait a few days for an equipment to become available to run some tests.

Regarding this case:

cegerer said:

ON for Adv, OFF for Scanner does not work

From Bluetooth Core Spec Vol 3 Part C Section 10.7, a connection initiator using Privacy features cannot initiate a connection with a peer who doesn't have Privacy. So this is expected.

As for this case,

cegerer said:

OFF for both devices (Adv/Scanner) does not work

This is not right, and we are investigating.
We found a strange implementation in the Zephyr Host that explains the behavior but still haven't fully traced the history behind this implementation yet.

For the time being, please try to workaround this issue by:

1. Replace the first argument in the line below with BT_LE_EXT_ADV_NCONN_IDENTITY.
   https://github.com/nrfconnect/sdk-zephyr/blob/ncs-v3.2.4/samples/bluetooth/periodic_adv_conn/src/main.c#L186
   
   
2. Add CONFIG_BT_SCAN_WITH_IDENTITY to periodic_sync_conn.

Best regards,

Hieu

[cegerer]

Hi Hieu,

thanks for the feedback! Will continue to work with privacy enabled for now.

Best regards,

Christian