Generic on/off model for transferring messages (8 bytes) over mesh

[NikhilIngale]

Hello,

I am using light switch example for mesh with the help of BT840 module as client and 2 BT832 as servers. I have also integrated UART in both the applications to debug and send the data to other MCUs (only one at a time). I have edited the generic on/off model and added 7 more bytes in the same model and tested it with one client and 2 servers. But it the bytes are getting received on servers after some time (1.5 - 2 seconds). Can anyone tell me the exact point why there is delay from server side to reply to the messages from client. When i press the button on BT840 module i can see the data (requests) is getting transferred instantly but sever side it is receiving after 1.5 to 2 seconds. All the modules set up is on bench only (placed hardly at distance of 0.5 meters). 

I have also gone through creating new model for message transfer but before that i want to understand the on/off model first.

Thanks in advance...!!

[Amanda Hsieh]

Hi Nikhil,

Can anyone tell me the exact point why there is delay from server side to reply to the messages from client.

 This mesh blog post says this about mesh latency:

"The network latency and node power consumption depend on how much of the time is spent on scanning and advertising. The latency is on average 15ms per-hop and the power consumption of the nodes is largely determined by the receive current (if everything is configured for minimum latency which means radio is on close to 100% of the time)"

It makes sense that the unreliable communication you receive for 8 bytes of data sent is slightly quicker than the reliable messages since the sender does not get an acknowledgment back from the receiver. If you use the proxy functionality, this would split up the radio time between mesh & GATT proxy, leading to increased latency. 

Please also see this post. 

i want to understand the on/off model first.

The Generic OnOff model is a model which defines a single state, called Generic OnOff, which may have a value of 0x00 representing Off or 0x01 representing On. 

The Generic OnOff model should be used in real applications using the mesh, from infocenter:

Important: The Mesh Model Specification specifies a model called the "Generic OnOff Model", which should be used in real applications using the mesh. However, the example model described in this guide is simpler and serves as a nice introductory example for creating a custom mesh model.

Here you can also find a guide on how to create new models.

Please see this post.  

-Amanda H.