RE: Frequent mesh device power cycle makes it unable to communicate after a while

rmarques — Tue, 08 Sep 2020 13:58:12 GMT

Hello Mttrinh, you've been helpful, thank you.

We have to take care about what we changed on the nordic SDK to be able to make an update to the Mesh SDK, but it is nice to know that that work will be useful to benefit from that 4.0 feature.

RE: Frequent mesh device power cycle makes it unable to communicate after a while

Mttrinh — Tue, 08 Sep 2020 13:53:37 GMT

Hi,

The sequence number can only be reset after the end of the IV update procedure. One of the requirement of the Mesh specification is "If the node is added to a network when the network is in Normal operation, then it shall operate in Normal operation for at least 96 hours." Because of this, an internal IV update procedure in the mesh stack will not trigger before at least 96 hours.

Regarding your issue, there is a timer for monitoring the IV update procedure, and will avoid triggering the IV update procedure if it has been triggered less than 96 hours. When the device resets, this timer will also reset. Resulting in that the node would never request IV update procedure (to reset sequence number) and end up running out of sequence number. This issue has been fixed in Mesh SDK v4.0 that we store the timer every 30 minutes to flash. This way if the node get reset, the time will start counting from last saved time then still can trigger a IV Index update in relatively correct 96 hours.

Is it possible to upgrade to our latest Mesh SDK(v4.2)?

This might also be useful.