NRF Mesh app related query (iOS)

[ArpitA]

Hi,

I need to understand about the group and application key used in NRF Mesh App.

Please explain usage of multiple groups and multiple Application keys.

What is the the limitation to use  application keys ?

How many group can be handled at a time?

How many Application keys can be used in a group at a time?

How groups and application keys can be communicated?

Please response in detail.

Thanks!

Regards,

Arpita

[Edvin]

Hello Arpita,

What is the the limitation to use  application keys ?

What do you mean by limitations?

The purpose of different application keys is that you may want to have different level of security. Not different levels strictly speaking, but dividing the nodes into separate groups, where you can say that for instance if you want to access a Mesh doorlock, you need to have that specific application key. If one of the nodes (let us say a light bulb) is hacked, but it didn't have the application key used for the door lock, then the attacker will not be able to unlock the door.

Regarding distribution, these keys are distributed through the provisioner (the phone app, for instance).

Best regards,

Edvin

[ArpitA]

Hi Edvin,

May I know how many DCS can be added in a group using same application key.

Thanks!

Regards,

ArpitA

[Edvin]

I don't think there is any limitation on this. You can e.g. have thousands of Mesh Light Bulbs using the same application key.

BR,
Edvin

[ArpitA]

Hello again  Edvin,

Thanks for quick response!

How many groups can be created and they can communicated , and each group required unique application key, and please explain how group and application keys getting mapped .

If we connect 1000 DCS at a time, is there any chances to loss packet?

Best Regards,

ArpitA

[Edvin]

I think you just need to start experimenting. 

How many unique application keys do you need?

How many groups do you need?

Groups and application keys are not really related, so they are not being mapped. Everything is set up from the provisioner (nRF Mesh phone app). 

The only limitation I can think of is thr group address. It is 2 bytes, and I think half of them are restricted (because they are unicast adresses), so that leaves you with 32000 group addresses that you can use as you like (this is the same number of nodes you can have in a network, because every node needs a unicast address). 

BR,
Edvin

[Edvin]

Regarding packet loss, this is a concern in Bluetooth Mesh. The throughput in a network is limited, and the more nodes you have that try to send packets at the same time, the higher is your chance of packet loss.

Mesh is ideal for one-to-many messages, such as one light bulb telling thousands of light bulbs to turn on or off.

Mesh is not ideal for many-to-one messages, such as thousands of temperature sensors trying to report their temperature to a gateway.

There are no definite limitations. The performance gets worse as the network increases, and as traffic per node increases. You simply have to test to see what sort of throughput/performance you get.

BR,

Edvin