https://devzone.nordicsemi.com/f/nordic-q-a/22649/icmp-in-openthreadHi All, Can one safely assume when sending a packet to a destination address using the ping command in the CLI, that the payload echoed back is the payload transmitted initially?en-USTelligent Community 13Mon, 19 Jun 2017 10:07:53 GMThttps://devzone.nordicsemi.com/thread/89073?ContentTypeID=1Mon, 19 Jun 2017 10:07:53 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6828041d-4f15-42f0-8ab9-cacf3af7b15bRoger<p>Hi Krzysztof,</p> <p>Thank you very much for the detailed answer. I&#39;ve also noticed the <code>ThreadError otIcmp6SendEchoRequest(otInstance* aInstance,otMessage* aMessage, const otMessageInfo* aMessageInfo,uint16_t aIdentifier)</code> function in the API which I will adapt to my needs.</p> <p>While I was sending ICMP echo request (10 bytes per second for 1000 iterations) from the CLI, I noticed that some sequence numbers displayed on the CLI was skipped. I&#39;m thinking that these must be packets that got lost during transmission and weren&#39;t acknowledged by the sender.</p> <p>Best regards,</p> <p>Roger</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/89072?ContentTypeID=1Mon, 12 Jun 2017 14:23:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2387ad82-2ec9-4029-bf80-5a296471ac13Krzysztof Loska<p>Hi Roger,</p> <p>Yes, this assumption is true. To be even more precise, when you send Echo Request packet using CLI, a timestamp is attached as the payload. Look into <a href="https://github.com/openthread/openthread/blob/master/src/cli/cli.cpp">cli.cpp file</a> line 1599 - method ProcessPing() calls method HandlePingTimer() to do that. Echo Replay sends the payload back. For reference look into <a href="https://github.com/openthread/openthread/blob/master/src/core/net/icmp6.cpp">icmp6.cpp file</a> line 185 - HandleEchoRequest() method.</p> <p>Best regards,</p> <p>Krzysztof</p><div style="clear:both;"></div>