low power node without friendship

[Young]

Hi Support team,

nrf5 sdk for mesh 5.0,  nrf5 sdk 17.0.2, s132, SES;

We are trying to understand the LPN feature based on the LPN example because in our scenario there are a few node in the mesh network which will work under low power mode.   These low power nodes (such as switches) don't need to receive messages, so we really want to implement the solution without the friendship, without the friend nodes.

The low power node just works like this: the gpio interrupt wakes up the node and sends a message, and then go to sleep.  We have considered the iv update: in the life of the low power node, the sequence number cann't be wrapped since the number of the sent messages is not large enough. 

Is it possible to implement the solution like that mentioned above? And where should we change from the lpn example? 

If it cannot be implemented based on the LPN example, is there a nother approach making the node work under the low power mode (like the above description)? 

Thanks in advance!

[Simonr]

Hi

I'm sorry, but that's not how a Mesh network, or LPN works. In any Mesh network there are IV values and possibly changed security information, so they will have to do the listening/receiving at some point. The LPNs are based on having a friend node, so what you're explaining is a normal Mesh node that only transmits messages, but it will still have to wake up and listen at least once a week to get the updates in the Mesh network. Are you sure you require a Mesh network for you use case at all, and that a BLE star network won't suffice if the beacons/nodes are only meant to transmit very rarely?

Best regards,

Simon

[Young]

Hi Simonr,

Thanks a lot for your patience for my question.

I have read the LPN feature introduction in the infocenter page. Actually we want to implement the solution like this:

1. one or more switches (just transmit unack messages, not receive the messages from other mesh nodes such as lights)

2. a couple of lights (just receive messages, not transmit messages)

so I think the sequence number of the light will never exhaust, and the switch will increment the sequence number and initiate the IV Update procedure, do I understand right? 

And then I think the friendship is not necessary for the switch(powered on battery). Is my understanding right?