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Jlai.9
Jlai.9
Associate
August 29, 2019
Question

How to send packet between mesh nodes by BLE_MeshLightingDemo Example.

  • August 29, 2019
  • 2 replies
  • 1490 views

Hi Sir:

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I try to use BLEMesh_SetRemoteData(..) with Unicast Address from BLEMesh_GetAddress() for sending packets between two nodes, but the received node dosn't call the Vendor_WriteLocalDataCb().

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Is there any suggestion for me to send the packets with manually fiiled payload between Mesh nodes ?

Thanks,

Jack

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This topic has been closed for replies.

2 replies

EMECH
EMECH
ST Employee
August 29, 2019

​Hi Jack,

What is the use case ? What do you mean by sending packets ?

Just for information, Bluetooth Mesh packet sizes are 15 bytes for unsegmented messages (unack'd/unreliable), however, it is also possible to send a segmented/reliable message which can consist of 12 bytes per packet (3 byte packet overhead for segmentation) with a 32 segment max, which would yield a 384 byte total message size.

Obviously, segmented messages are much slower than unsegmented due to the required ack'd response from the receiver.

It is not possible to send 1KBs in a single packet or even feasible to send over multiple messages.

You should note that Bluetooth mesh in its current version (v1.0) is primarily targeted at command/control type applications and therefore the concept of flooding 1K bytes across the mesh is not a primary or expectant use case.

Hopefully Mesh v1.1 will deliver an additional bearer layer which incorporates advertising extensions and additional throughput enhancements, to be confirmed. 

Best regards.

lukasz2
lukasz2
Associate III
January 27, 2020

Hi EMECH,

How to send and receive segmented message?

Correct me if I am wrong. If I send 100 bytes of segmented message, means that BLE Mesh handle all internal communication and on receiver I get complete data of 100 bytes?

And one more question, is it possible to write "default provision data" by user application from CortexM4 STM32WB? I want to avoid use smartphone to configure each node.

Best Regards

EMECH
EMECH
ST Employee
August 29, 2019

​Jack,

Before the 2 nodes has to be provisioned, and configured with the smartphone Mesh application.

The Client node have to be configured as a publisher to the Server node.

The Server node have to be configured as a subscriber to the Client node.

On the application SW side before using the BLEMesh_SetRemoteData() function, you have to get the publish address (a provisioned node can publish to One node or Group) with the BLEMesh_GetPublishAddress() function.

BLEMesh_GetAddress() function give the address of the node that will publish, no the publication address node.

You have an example of the functions use in the function BLEMesh_ModelsCommand() of the models_if.c file.

This function is called each time there is a short SW1 button press.

Best regards.

Best regards.

Jlai.9
Jlai.9Author
Associate
August 30, 2019

Hi Eric:

Thank you for your information, but I am not familiar with BLE mesh.

So I still have few questions!

(1)

I have two nodes provisioned, and the send message like below.

Can I send the message like this?

Send Node:

Unicast Address: 0x0003 from BLEMesh_GetAddress()

TX:

#define TX_DATA_LEN 5
 
MOBLEUINT8 tx_data[TX_DATA_LEN] = {0x00, 0x01, 0x02, 0x03, 0x04};
 
MOBLEUINT32 tx_data_len = TX_DATA_LEN;
 
BLEMesh_SetRemoteData(0x0004, 0x00, APPLI_LED_CONTROL_STATUS_CMD, tx_data, tx_data_len, MOBLE_TRUE, MOBLE_FALSE);

Receive Ndoe:

Unicast Address: 0x0004 from BLEMesh_GetAddress()

RX:

MOBLE_RESULT Vendor_WriteLocalDataCb(MOBLE_ADDRESS peer_addr, 
 
 MOBLE_ADDRESS dst_peer, 
 
 MOBLEUINT8 command, 
 
 MOBLEUINT8 const *data, 
 
 MOBLEUINT32 length, 
 
 MOBLEBOOL response)
 
{
 
 // Not going into here...
 
}

(2) How to configure Client/Sever Node to publisher/subscriber ?

Best regards,

Jack

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