Transaction Identifier in BLE mesh messages

[Mela]

Hi,

I have a question about the TID field in Generic OnOff set message. I am using two nrf52840 boards and a Light-Switch example included in the mesh SDK_v5.0.  I have enabled logging via RTT for the example to see when the message gets sent from the client and when the server receives the message.

In the Debug Terminal area (Client) I see for example:

<t:    9027644>, access.c,  425, TX: [aop: 0x8203]
<t:    9027646>, access.c,  426, TX: Msg: 82030071010A

 

And in the Debug Terminal (Server) I see:

<t:    8278237>, access.c,  253, RX: [aop: 0x8203]
<t:    8278240>, access.c,  276, RX: Msg: 0071010A
<t:    8278866>, main.c,  142, Setting GPIO value: 0
<t:    8278869>, main.c,  159, Transition time: 0, Target OnOff: 0

 

Considering that the first field in TX message is OnOff, the second is TID and the last two are Transition Time and Delay. In this case TID is 71 (113 decimal).

Does this mean that the Client has sent 113 messages to the server so far?

 

Best regards!

[Mttrinh]

Hi,

Yes, that is correct. The TID field is a transaction identifier indicating whether the message is a new message or a retransmission of a previously sent message, as described in Section 3.4.1.2.2 in Mesh Model 1.0.1.