Missing connect requests

[MKJ]

We are using the soft device (s140) in SDK version 16, our device is configured as a peripheral.

I have a program that connects to and then immediately disconnects from our peripheral device as fast as possible (obviously dependent on the advertising parameters, etc). I am monitoring the behaviour using Wireshark.

I find that occasionally the stack seems to miss the connection event even though I can see the connection request on Wireshark. I have put relevant debugging into the BLE event handler specified in  NRF_SDH_BLE_OBSERVER() and the connection event does not appear there. So it would seem that the stack is missing connection requests. Is this normal/possible? There is little or no other BT traffic.

[Karl Ylvisaker]

Hi,

Could you be more specific with what you mean when you say "occasionally", how often is this roughly occurring?
It is possible for a packet to be corrupted from interference, even when the amount of possible interference sources seems minimal.
Could you provide the Sniffer log from Wireshark, so I may take a look at it?

Best regards,
Karl

[MKJ]

ConnectFail.pcapng

Here's the wireshark log the peripheral device address is  F9:45:36:CE:2C:3B

Occasionally - one in ten

[Karl Ylvisaker]

I could not find anything unusual in your log, regarding the missed connection request.

Missing one in ten connection requests however does sound normal, depending on local interference(not just from other Bluetooth communication, but everything on the 2.4 GHz frequency). Normally the central will assume connection after a connection request, but when it falls through you can just send another connection request immediately.

Best regards,
Karl

[MKJ]

Ok, thanks - it was just that I could see the  connect request on Wireshark but of course that device is in a different position to the peripheral under test.

[Karl Ylvisaker]

No problem at all, I am glad to help!

You are correct, the sniffer will sometime be able to receive packages that other devices does not, and vice versa - depending largely on its position relative to sender, but also on the general interference on the 2.4 GHz frequency and obstacles in the path of the signal.

Best regards,
Karl