relay node in mesh

[ps_anu]

i am using three boards , one is client (nrf52840) and other two boards as server(nRF52832) using light switch example . i want to get the message from  client board ,to relay node and from relay node to server. i want to do hopping from A ---B-----C using relay . 

1.  what are the changes i need to do in light switch example (both in client and server)

2. how to publish /subscribe in nRF mesh app for these three boards  one client , one relay node and another server , procedure to achieve this .i am placing the A and C nodes far away which is not in the range of A . 

anyone have done this please guide me 

thanks in advance 

[tesc]

Hi,

In Bluetooth mesh you never think about what route a particular message will take through the network. All you need to do for messages to reach their destination is to provision all the nodes into the network. Then everything will work as long as the network is contiguous (and as long as the path that a message must take is shorter than the configured time to live.)

For configuration, node A should publish to the address of node C or to a group address that node C subscribes to. It should also use an application key. If you used a group address, then node C must subscribe to that group address. Node C must also use the same application key.

Regards,
Terje

[ps_anu]

Thank you for your response tesc. Do you understand my question.  Actually I want to send the message from A (client ) ----B (server 1which acts as relay node) ------C ( server 2). I want to do hopping from one node to another and so on and should reach the destination .how to do publish /subscribe ?

I know only Unicast address of each device .. which address I should give for subscribe. Can you clearly explain me 

Thanks in advance

[ps_anu]

please have a look below , this is the algorithm i want to do 

• Each node acts as both a transmitter and a receiver.
• Each node wants  to forward every message to every one of its neighbors except the source node.
• want to forward the message from one node to the nearest node which is in range 

how to do this ?  

[tesc]

Hi,

If you want to send one message to two nodes, then you can use a group address. Configure the client to publish to the group address. Configure the two servers to subscribe to the group address.

In Bluetooth mesh you don't have control of the specifics regarding where messages travel, as awneil has explained very well already. What is the motivation for wanting to control the forwarding of messages? What do you get from that, what is your end goal?

Regards,
Terje

[ps_anu]

By this ,i can achieve longer distance node . i want to transmit the data for a long distance so that my destination node  will be not dependent on source node.

[awneil]

ps_anu said:

this is the algorithm i want to do

So you are trying to develop your own Mesh protocol, then?

Because what you describe is not how BLE Mesh works!

Perhaps you should investigate (some of) the other Mesh Network standards (eg, Zigbee, Thread) before re-inventing this wheel?

https://www.google.com/search?q=comparison+of+sensor+mesh+networks

tesc said:

What is the motivation for wanting to control the forwarding of messages? What do you get from that, what is your end goal

Indeed!

http://www.catb.org/esr/faqs/smart-questions.html#goal

[tesc]

Hi,

ps_anu said:

i want to transmit the data for a long distance so that my destination node  will be not dependent on source node.

And that is exactly what Bluetooth mesh does, without any configuration. The message will take multiple hops until it has spread through the whole network. (Up until a configurable maximum number of hops known as the Time To Live (TTL), ranging from one to 127 hops.)

Regards,
Terje

[ps_anu]

yes i have tried. but i am not getting message to node c . Tell me how to do this in nRF mesh app or using provisioner . please guide me

Thanks in advance 

[tesc]

Hi,

Have you tested this with the light switch example, in particular followed the section Testing the example thoroughly?

First get the example up and running, and confirm that you get communication through multiple hops with the configuration set up by the static provisioner. (Or, with the configuration described in the "Evaluating using the nRF Mesh mobile app" if instead you use the nRF Mesh app for the provisioning.)

When that one is working properly you can have a look at how to configure the nodes differently in order to suit your particular scenario of one button (node A) controlling two lights (node B and node C).

Regards,
Terje

[arpita]

even i am trying same as saral is doing. i have the same question what is publication and source address to give if i want to relay from one server to another with "nrf mesh mobile app". 

[tesc]

Hi,

You bind the same application key to client and server. Then you either:

• configure the client to publish to the server unicast address, or
• configure the client to publish to a group address and configure the server to subscribe to that same group address.

After that, whenever the client publishes a message that message should propagate through the network and reach the server.

All you need to do is the configuration in the "ends" (client and server.) How the message is relayed is automatically handled by the network. Both clients and servers can act as relay nodes. The relay feature is not related to mesh models.

Regards,
Terje

[awneil]

arpita said:

i am trying same as saral is doing

Perhaps some background reading will help - especially in understanding the terminology:

https://devzone.nordicsemi.com/f/nordic-q-a/45818/about-mesh-network/180515#180515