BLE Mesh 4.0 send notification to all GATT connections

RE: BLE Mesh 4.0 send notification to all GATT connections

tesc — Wed, 05 Feb 2020 12:23:11 GMT

Hi,

From the viewpoint of the application, all nodes in a Bluetooth mesh network are addressed exactly the same way, and you always operate on models. That includes for instance node configuration, where you use the configuration model. Even the provisioner is a "normal" node on the network in this sense.

GATT is nothing but just another way for nodes to join the network. Just as there are no methods to specifically send messages to nodes connected over the ADV bearer, there are no methods to specifically send messages to nodes connected over the GATT bearer.

What this all means is, for any mesh node (including smartphones), you communicate to and from that node using the mesh models only. For instance by using access_model_publish(). There is no separate GATT communication channel.

From your descriptions, it sounds like you ask for the default configuration for the Light switch example. Note how among the descriptions for how to test that example, it reads: "you can also press Button 1 on the servers to locally toggle the state of their LED 1, and the status reflecting this state will be sent to the client board." I suggest that you look into the Light switch example, and in particular the configuration part.

Regards,
Terje

RE: BLE Mesh 4.0 send notification to all GATT connections

SET — Wed, 05 Feb 2020 08:02:18 GMT

Hi,

You are right, I tackle this problem from the transport layer, because I don't see how I can create a message for GATT on the application layer. In the mesh_gatt.c there is the m_gatt.connections[i], which contains all GATT connections to smartphones, so I think I need somehow this handle on the application layer. When I look in the access layer, I can use access_model_publish(access_model_handle_t handle, const access_message_tx_t * p_message), but this handle is for a model and not for a GATT connection.

So, how can I send a message directly to a GATT connection?

RE: BLE Mesh 4.0 send notification to all GATT connections

tesc — Tue, 04 Feb 2020 14:01:54 GMT

Hi,

There still should be no reason to hook into the stack on the transport layer. (Which you do when directly using mesh_gatt_packet_send().) As the smartphone is a proper node in the network you should use the access layer (through the Access layer API) for sending messages.

I must admit I still do not quite understand what your use case is, what nodes are involved, and what kind of notification is going from what node to what node and when. Can you elaborate, possibly with a figure / drawing of the network?

Regards,
Terje

RE: BLE Mesh 4.0 send notification to all GATT connections

SET — Tue, 04 Feb 2020 13:04:53 GMT

Hi Terje,

I think you missunderstood my question. What I want to achieve is to send notifications to the smartphone from a connected node in the mesh network. The problem here is, that when I send a network PDU with mesh_gatt_packet_send() from the light control examples, I receive the message on the phone, but the additional header data seems not to be included. This header data should include the nid, the ivi etc... How can I generate this additional information for the network PDU?

RE: BLE Mesh 4.0 send notification to all GATT connections

tesc — Tue, 04 Feb 2020 12:21:55 GMT

HI,

Whenever the server model is updated, it will send out a Status message to its configured publish address. (This happens in addition to any Status message sent directly as an answer to an acknowledged Set message..) This means you should have the corresponding client model on the smartphones, all subscribed to the same group as you set as publish address on the server model.

While there is a predefined group address for all proxy nodes (0xFFFC, all-proxies), there is no such address for "all nodes connected over GATT to a proxy". This means you must configure the address yourself on each smartphone. (In any case it is a good thing to be able to configure the network as you want, e.g. it will be possible to configure non-GATT devices to subscribe to the Status updates as well.)

Regards,
Terje