How to determine hops used for a Thread message?

[Mary]

HW: nRF52840 custom board
SDK: NCS 1.9.1

We have a project based on the OpenThread coap_client and coap_server.  We have one server and several clients.  We plan to offer what we call "Repeaters" that are simply mains powered FTD devices that can act as routers in cases where a client is far from a server, or there are obstacles in between.

Is there a way to know if the "Repeater" is actually being used to forward messages?  We would like to know for testing and possibly in operation.

Can the receiver find out how many hops were used to send the message it received? Or the sender find out?

Can a router know (and maybe count them, or blink or something) when it is forwarding messages?

Thanks,

Mary

[Jørgen Holmefjord]

Hi,

I'm looking into your question.

The details about hop limit is certainly available to the routing nodes, as the hop limit is decremented every time a package is forwarded. I'm uncertain if the final hop limit is available to the application on the receiver side, and also if the original hop limit is available (if you have control over both sender and receiver, you should also have control of this number).

I will let you know when I have more details to share.

Best regards,
Jørgen