low power node without friendship

RE: low power node without friendship

Simonr — Thu, 21 Jul 2022 08:07:19 GMT

If the switches also do listening to get any IV/security updates (from the provisioner for example) once every week or so this should be fine I think.

Best regards,

Simon

RE: low power node without friendship

Young — Wed, 20 Jul 2022 14:47:13 GMT

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?

RE: low power node without friendship

Simonr — Wed, 20 Jul 2022 09:27:31 GMT

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

RE: low power node without friendship

Young — Tue, 19 Jul 2022 10:58:59 GMT

Hi Simonr,

I have tested the LPN example (nRF5 SDK for Mesh 5.0), the current is around 5 or 6 uA and the onoff message can be sent well. Now I want to make my project based on the LPN example for the low power device. The low power device will only send messages, and will not receive any messages, so we will not implement the friendship for the low power devie, which means in our mesh network there are no friend nodes. Is there anything needed to consider for our low power device project?

RE: low power node without friendship

Simonr — Tue, 19 Jul 2022 09:24:46 GMT

The "this page" link only leads to this DevZone ticket, did you perhaps upload the wrong link? I would recommend having your battery powered nodes be LPN nodes, and then have stable friend nodes that forward data to them.

Best regards,

Simon

RE: low power node without friendship

Young — Tue, 19 Jul 2022 02:06:45 GMT

In fact, in the real scenario, it is quite possible that all the friend nodes have been out of the mesh network for a little long time (greater than the poll timeout), however, according to the introduction about the Low Power node feature on this page , the LPN node will go to the high power option mode once the friendship terminates. For a battery based device, it absolutely cannot put up with this kind of situation.

We just want to implement a private local mesh network, not interact with other standard mesh network or nodes. How to make a battery based device take part in the mesh network? Is there a feasible approach for this kind of implementation?

RE: low power node without friendship

Simonr — Mon, 18 Jul 2022 13:19:34 GMT

I'm afraid the LPN node is only possible with friend nodes, as an LPN uses the friend node to be able to participate in the mesh network. You can have multiple LPNs befriending one Friend node though, if that helps. But how this works is that the LPN node wakes up periodically and polls the friend node for any new messages. The friend node then delivers any updates to the LPN. Here is more information on the LPNs in a Mesh network.

Best regards,

Simon

RE: low power node without friendship

Young — Mon, 18 Jul 2022 10:25:08 GMT

I learned about the low power mode from the LPN example, which is that except for the receive windown the scanner stays in the disabled state. Is just diabling the scanner to make the device sleep and work under low power mode? Is there other places that should be taken care of ?