Hi Johan,
Thanks for your quick response.

All application-level messaging with mesh is always in the context of models. I’d suggest familiarising yourself with the Mesh Model Specification to see if any of the standard models suits your needs.

I already have gone through the mesh model spec, but I don't think there is a model that I could use to do what i want. I would like to send a message looking like this : UUID_A, UUID_C, RSSI_C.
I have not found a model that allows me to send a specific message (I might be wrong of course), so I don't know what model or at least what kind a model I could use.
EDIT : I think I will have to create a new model (a vendor model if I am right). I don't know if there is some kind of guide to do so, but there is a vendor model in the onoff_level_lighting_vnd_app that I could rely on it's implementation.

The heartbeat is a mesh transport layer feature. You can find a description of it in section 3.6.7 of the Mesh Profile Specification. The sending and receiving of heartbeat messages is configured using the configuration model, however it sounds like this is not what you are looking for since the heartbeat message is not extensible with any additional payload.Since you say you need periodic sending it sounds like periodic publishing for a model is what you are after (see section 3.7.6.1 in the Mesh Profile specification). Model publishing is also configured using the configuration model.

I did not see this section, thanks for the info.

Zephyr doesn’t support acting as provisioner or a configuration client (except for local configuration), however many of the mesh apps available for phones can do this (e.g. nRF Mesh). Did you have something specific in mind to use as the provisioner and configuration client?

I am using nRF Mesh to act as a provisioner right now.

I’m not sure I understand your question, however it is possible for a Mesh node to listen for other advertising packets, such as those coming from a non-mesh beacon. At the moment we’re missing a clean API for it, so you’d need to modify the scan callback (bt_mesh_scan_cb function) in subsys/bluetooth/host/mesh/adv.c to handle any non-mesh advertisements.

You did understood what I meant. I will look further into it once I will be able send a message in my mesh network.

Regards,
Paul.