How i use "InstaBurst feature" for sending large amount of sensor data in mesh network?

Question

Hi, 
 We have developing ble mesh network using nRF52 mesh sdk is 1.0.1. We have large amount of sensor data it near about 24-25 kb and want to send this data to other node in single message. 
 Actually i have refer this link_refer for doing this. I have enable this "EXPERIMENTAL_INSTABURST_ENABLED" and added required source files then complied code. 
 When i define large length is gives error code 9 means invalid length. 
 For sending this all data to server i am using this method: 
 #define SAMPLE_POINTS 4096 
 uint8_t value[SAMPLE_POINTS*2]; 
 status = simple_message_client_send(&m_clients[GROUP_CLIENT_INDEX], &value[0], sizeof(value)); 
 I have few question for sending all data as following: 
 
 Is it possible to send 24-25kb data in single message, if yes how i can send? 
 If not able to send this kind of data is it have other solution for sending all data in ble mesh network? 
 Once i enabled InstaBurst feature is it required specific soft-device version if yes which one? currently i am using sd132_nrf52_3.1.0. 
 how i can use InstaBurst feature and send data via this feature for large packet length and high through put? 
 
 Looking forward your reply....!! 
 Thanks in Advanced...

tesc · Accepted Answer

Hi, 
 Please note that Bluetooth Mesh is best suited for use cases where you have many nodes, possibly over a large area, but where the required data throughput is low. Although Bluetooth Mesh was not written for large data transfers this may still be possible although not in one message and only with low frequency (ref. DFU , which uploads full firmware binaries.) 
 1. Although our Instaburst feature uses extended advertising, it is limited to the auxiliary packet and a single chain packet. We provide some performance numbers in the Nordic Advertiser Extensions (Instaburst) chapter of the nRF5 SDK for Mesh documentation, and it states that you get 498 bytes of advertising data over the bearer for every advertising interval. Subtract overhead throughout the stack and you are left with around 1/3 of that as access layer payload. With maximum 32 segments that becomes approximately 32 * 498 / 3 = ~5k, which is 1/5 of what you ask for. 
 2. As long as the total throughput is low enough you may of course split up the data in as many messages that you want. This resembles what we did for DFU: In order to send large files we are sending packets of smaller size which are assembled to the full firmware binary after reception. 
 3. Our Mesh stack in the nRF5 SDK for Mesh has its own implementation of the required Advertising Extensions for our Instaburst feature. Support for those features is not required from the SoftDevice, and s132 v3.1.0 should work perfectly well. 
 4. Please see the "Usage in the mesh" section of the Nordic Advertiser Extensions (Instaburst) documentation on Infocenter. 
 Regards, Terje

How i use "InstaBurst feature" for sending large amount of sensor data in mesh network?

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