Disconnect latency after calling bt_conn_disconnect()

[kpreiss]

Hi,

Our application is running in the central role connected to a peripheral.  The app disconnects from the peripheral by calling the bt_conn_disconnect() function.  It appears to take from 1 to 2 seconds before the "disconnected" callback handler is called.  There is no data being pushed out over the link prior to calling the disconnect function. The connection interval is 1 second, 0 latency with a 4 second supervision timeout.  I would expect the worst case latency would be 1 second.  Is this expected?

nrf Connect SDK 2.4.4
nrf5340

Thank you

[Turbo J]

No, you would expect 2 seconds here.

One second to get the "disconnect" packet out, another second to get the answer "packed received" in. Its unusual for hosts to be able to reply within the very few µs between BTLE packets in a single connection exchange step.

[kpreiss]

Hi,

Thank you.  It appears that the disconnect command is transmitted by the central and gets "ACKd" immediately with the empty PDU packet.  I don't see the peripheral respond with an acknowledgement other than the Empty PDU packet.  The disconnection occurs after the peripheral responds to the LL_TERMINATE_IND packet which I think should occur immediately.....