Mesh provisioning limitations

[Rob Johnson]

Hello,

I have been using another vendors mesh stack to develop a product that uses mesh networking, however, their stack is limited to storing provisioning data in a certain area that I cannot augment. As a result I would be unable to provision more than ~20 nodes using their stack as a provisioner. This is unacceptable for my application.

Are there any hard limits (beyond the limitations in the mesh standard) to the number of devices that can be provisioned with the Nordic mesh 2.0.1 SDK? I looked at the memory manager used in the mesh SDK and it seems as if it can scale as much as is needed. I will need a device that is capable of provisioning ~200 nodes.

Can external memory be used for provisioning data as well if needed?

Thanks in advance,

Rob

[leonwj]

hello,

There are a number of previous posts (see links below) within the forum which cover your queries (if not individually, then in their entirety) which should provide you with some guidance...

1. https://devzone.nordicsemi.com/f/nordic-q-a/32510/large-scale-bluetooth-mesh-network-hundreds-of-nodes/130293#130293
2. https://devzone.nordicsemi.com/f/nordic-q-a/32864/mesh-provisioner-recovery
3. https://devzone.nordicsemi.com/f/nordic-q-a/32953/how-many-device/126951#126951
4. https://devzone.nordicsemi.com/f/nordic-q-a/33197/how-many-mesh-nodes-can-be-managed-by-a-provisioner/127548#127548

You haven't provided any info on whether you have to use an nrf5x SoC as your preferred provisioner or if it's possible (within your architecture) to offload the function to a smartphone/tablet or gateway type device. I would suggest reviewing the included posts and getting back should you have additional questions and to let us know about your planned provisioning device.

Regards,

[Rob Johnson]

Hello Leon, thank you for the links. I have seen a couple of those threads but hadn't seen #1 which was the most pertinent here.

A phone or a tablet wouldn't work well for our application but some sort of single board computer might. The biggest reservation I have about using a gateway to provision and configure the network is lack of experience, we have several engineers who can work with microcontrollers but no one who has worked with embedded linux. 

I guess the main question that I still have is whether the memory manager can utilize external memory or if it is restricted to using the on-device flash. I read through the API reference for it and have the impression that it might be limited to the device flash, but am not certain.

Thanks,

Rob

[leonwj]

Hello Rob,

As specified in a few of the links above, the Bluetooth SIG has left the management of provisioning data up to each individual vendor and so the storage/accessing of that data is pretty much implementation specific.

I believe that there is an initiative underway by the Bluetooth SIG to define a JSON format for provisioning data and so if you want some insight this post may be on value... I would imagine that would allow a consistent cross-vendor approach via simple parsing of the JSON objects thereby negating the direct use of flash manager etc.)

Additionally, the nrf52840 does offer a QSPI peripheral for interfacing external flash memory, see this post.

Again, the idea would be that you manage your provisioning data as best suits your application (e.g. possibly reading from the memory manager and storing to external etc.)

Regards,

leonwj