https://devzone.nordicsemi.com/f/nordic-q-a/24622/to-avoid-lost-packageWhen i use sd_ble_gatts_hvx() send package,i can use the usb dongle get the data package,as it show i can get the information such as, LLID, MESN, SN,MD,PDU-Length show in the catch package tool, but if i can get that information at the return informationen-USTelligent Community 13Thu, 24 Aug 2017 07:57:29 GMThttps://devzone.nordicsemi.com/thread/96928?ContentTypeID=1Thu, 24 Aug 2017 07:57:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:09956a36-13f6-404e-af84-ff926343ff38run_ar<p>@hyw : Just check the error codes returened by sd_ble_gatts_hvx() to make sure you actually place the packets in the TX buffer.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/96927?ContentTypeID=1Thu, 24 Aug 2017 07:17:17 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6e344ec2-e118-4b98-8623-b4714a1a99c5RK<p>It’s fairly difficult to figure out what you are asking here. However since BLE is a reliable transport there’s no such thing as a lost packet (unless the connection actually breaks completely and you need to reconnect) so you’re trying to solve a problem which doesn’t exist.</p> <p>Eithe way none of that information is available at the application level, this is all handled by the soft device.</p><div style="clear:both;"></div>