What is the difference between subnet and group in BLE mesh?

[Milan]

Hi Team,

I am a bit confused in terminology used in BLE MESH PROFILE specs.

Can someone help me to understand the difference between subnet and group?

Are both the same?

Which parameters (key, id, etc.) differentiates the subnet and group?

Thanks!

[Hung Bui]

Hi Milan, 

 

Could you clarify what you mean by "group" ? 

There isn't a definition of group in mesh spec as far as I know. 

Are you thinking of "group address" ? Group address is just the address that multiple nodes can subscribe and publish to. 

The subnet is a group of nodes that share the same subnet (network) key.

[Milan]

Hi Hung Bui,

Thanks for the reply.

I tried to understand in more depth after posting this query.

What I understood is in a network there could be multiple subnets (separated by NetKey) and subnets may have multiple groups using group addresses.

Also, I understood that a node acting as a gateway device having multiple subnets in a mesh network need to remember NetKey to pass the message to that particular subnet.

Please confirm my understanding.

[Hung Bui]

Your understanding is correct. And any node that belong to multiple subnets would also need to remember all the netkeys of each network.