[nRF Mesh] how to know the secure network beacon is received by configuration server during the key refresh

[xiaolongba]

Hi Nordic Experts,

I completed the key refresh feature based on the latest mesh sdk(v4.2), but i still have one doubt about key refresh would like to ask. I have implemented this feature with the Config Key Refresh Phase Set. However, i looked into the spec and found that as soon as the first phase is complete (i.e. new keys (network and/or application keys) are distributed to each node), the provisioner will transmit a secure network beacon to tell the other nodes that each node has received new keys. so my question is 

if i used the Config  Key Refresh Phase Set Command, i can fully understand if the message is received by node as the acknowledge. but i used the secure network beacon, How can provisioner know the secure network beacons are received by nodes during the key refresh and then determine if it can go into the next phase? Could you give me a hand?

Many thanks.

[Hung Bui]

Hi Helon, 

The provisioner usually wouldn't check if the secure network beacons are received by all nodes. It would assume that the beacon will be propagated across the network and all nodes will receive the beacon at one point. 
If you have a specific need to get the phase of each node, it should send Config Key Refresh Phase Get message to each node. 

[xiaolongba]

Hi Hung,

Many thanks for your fast response. as you said, the provisioner doesn't need to wait for other nodes if they received the SNB or not. so provisioner will transmit the SNB(Key Refresh Flag = 1) after all acks from nodes are received during the phase 1, and then the provisioner goes into the phase 2. afterward, provisioner will transmit the SNB (Key Refresh Flag = 0) when it received the SNB(Key Refresh Flag = 1) and then it goes into the phase 3 until the key is revoked and then goes into the phase 0

the understanding above if it is correct?

thanks again

[Hung Bui]

Hi Helon, 

Yes your understanding is correct. The procedure is described at section 3.10.4 in the Bluetooth Mesh spec v1.0.1

[xiaolongba]

Hi Hung,

Thank you so much, bro. you can close this ticket now.