Could I use net_state_iv_index_set() to set the iv index at application layer?

[Young]

Hi Nordic,

nRF5 sdk for mesh 5.0, s132, SES

In the mesh network, there are transmitters and receivers. The receivers only receive messages and there are no messages to be transmited out from the receivers. So the iv index of the receiver will not exhaust its sequence number for ever.  Apparently the transmitter will exhaust its sequence number sometime, and the transmitter cannot initiate the iv update since it is a LPN node. So I want to use net_state_iv_index_set() to set both the iv index and sequence number to 0 periodically. 

Is it feasible? If I do like this, what should I consider?

[Young]

Hi Nordic,

I am trying to understand the iv update and the sequence number allocation.  There have been seqnum_block and iv_index, Why are there other two variables seqnum_block_legacy and iv_index_legacy?

How to understand the seqnum_block_legacy and iv_index_legacy?  

[helsing]

Hi Bo,

Just letting you know we have started looking at this. You will hear from us next week.

[helsing]

I will have another look at this next week. However, here are a couple of comments from the Mesh team so far:

"Regarding legacy functions. In Mesh version 4.0.0 flash representation iv index and sequence number have been changed. To allow backward compatibility between versions below 4.0.0 and above that during DFU procedure these functions have been added. It just understands variable representation in the flash if it is legacy version it is converted into actual one. If customer works with v5.0.0 it doesn't do anything."

"To trigger IV update procedure manually they need to take a look at this API:

https://github.com/NordicSemiconductor/nRF5-SDK-for-Mesh/blob/master/mesh/core/include/net_state.h#L149-L158"

[Young]

Hi helsing,

Thanks a lot for your quick reply.  I think I got the info I wanted.