what the TID (Transaction number) means?

[Phan_hai_hust]

Hello, I read in the documentation how to create a model, in the client model, which defines a struct: simple_on_off_msg_set_t {uint8_t on_off, uint8_t tid}.
I do not understand what the TID (Transaction number) means? Why use it?

[Joakim Jakobsen]

Hi.

TID (Transaction number) is supposed to be used to differentiate between which message is the "last" received command.
In Mesh, a sequence "On" then "Off" may be sent. But on the receiving side this might be recieved as "Off" then "On", depending on the route it took.
The TID let's you determine whih was the last command that was sent.

Which SDK are you working with?
I would suggest upgrading to the latest nRF5 SDK for Mesh (currently v.2.2.0), and looking at Generic OnOff instead of Simple OnOff.

Best regards,
Joakim.