What is the recv_rssi and recv_ttl in bt_mesh_msg_ctx?

[ImSoMeshy]

I’m using an nRF54L15 evaluation board obtained from a distributor and currently testing transmission and reception of large data chunks. I built a vender model and a custom function that print out the RSSI and TTL of the message received using recv_rssi and recv_ttl from ctx. 

From what I understand, Bluetooth Mesh messages longer than 8–11 bytes are segmented, and the resulting segments may reach the destination via different paths—for example, one segment might be relayed while another might arrive without going through a relay.

So what do recv_rssi and recv_ttl from bt_mesh_msg_ctx show? Which segment are they from? Can I view TTL of each segment individually?

Right now, I use bt_mesh_msg_ctx from handler function registered to bt_mesh_model_op.

[Simonr]

Hi

The recv_rssi is the RSSI of the received packet, so RSSI of the final stretch of the message.

The recv_ttl is decremented for every relay, so the received message should forward the message until the TTL reaches 0. https://docs.nordicsemi.com/bundle/ncs-2.3.0/page/nrf/protocols/bt_mesh/concepts.html#relays Why would you need to see the TTL of each segment? If you know what the initial TTL was, then that would be a pointer to how many times it has been relayed before reaching the device you check.

Best regards,

Simon

[ImSoMeshy]

I just want to clarify what is the TTL value here telling as each segment can be relayed independently. Is it the minimum TTL of all segments or is it the TTL of the last segment like the RSSI?