Mesh Key refresh approach questions

RE: Mesh Key refresh approach questions

Michele Piffari — Wed, 30 Aug 2023 15:53:18 GMT

do you know how can I trigger a key refresh procedure for all nodes being part of a Mesh network?
Provisioner need to write a Config message to a Proxy message? However, ho wcan I config a node to be a Proxy node using Nrf Mesh mobile app?

RE: Mesh Key refresh approach questions

Bjørn Kvaale — Tue, 21 Aug 2018 11:57:55 GMT

Hi,

Sorry for the delayed response. The way I understand it is that you need to provision & configure a node one at a time. Therefore, configuring multiple config servers via one config client is not possible.

Also, the provisioner keeps a track of all of the provisioned & configured nodes, including all of the keys (appkey, netkey, device key) in a big database. The configuration client then fetches the relevant information it needs (like the device key) in order to configure the server device via the configuration server. Therefore, you can only configure one device at a time.

Kind Regards,

Bjørn

RE: Mesh Key refresh approach questions

$pider — Wed, 15 Aug 2018 07:51:05 GMT

Hi Bjørn,

I'm referring that in single cycle update the multiple nodes key means if somehow config client can bind to multiple config server in network at a same time then by executing config_client_netkey_update() those nodes received new key at a same time in single cycle. so is it possible that config client can configure multiple config server at a same time?

RE: Mesh Key refresh approach questions

Bjørn Kvaale — Wed, 15 Aug 2018 06:45:29 GMT

Hi,

Sorry for the delayed response. I would recommend reading the key refresh procedure in Chapter 3.10.4 of the Bluetooth Mesh profile spec if you have not already (it seems you have read this section already though).

1) You are correct that you can use the config_client_netkey_update() function to update the netkey via the config client on the provisioner & the config servers on the mesh nodes.

By single cycle, are you referring to the different phases in the mesh profile spec in Figure 3.48 Key Refresh Diagram.

2) Yes, 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.

If one of the nodes is powered off before it has received the new keys or right after it has received the new keys, the provisioner will know this & either wait for the node to be powered back on or update the powered off device's network key once it is back up & running. Either way, the mesh sdk takes care of this. If I were you, I would test this out yourself.

Kind Regards,

Bjørn