Mesh relay enable/disable

[Peter Gombos]

Hi!

We would like to install approx. 2000 pcs BLE devices in a mesh network. The device density is quite high (2x5 meters matrix, same level, no objects).

I think only couple of nodes should have relay functionality. Too many relays cause extreme network load, message cache overflow and ineffective network operation.

I plan to enable the relay function in 80 devices only. The distance between relays is 10-15 meters. The number of hops between the longest ends is about 20 hops, so TTL will be set to 24.

I plan to disable the relay, proxy and the advertisement functions in the normal nodes.

Is my approach correct? Will it work? What do you recommend to optimize the network? Shall I play with the retransmission parameters?

The next question is related to enable/disable relay functions: I would like to use the same fw in the nodes. Enable the relay is a configuration parameter. I couldn't find API function to do this. However there are public functions in the mesh source code core/include/network.h like network_opt_get/set. (mesh v5.0)

Is it recommended to use these functions to tune the relay function?

[Mttrinh]

Hi,

Your approach seems to be fine. Not having all your nodes in the network beeing a relay node is an intended way of doing it. Like you mentioned, having too many relays will cause a huge load on the network and disturbance between the nodes. 

As for your question regarding the API for enabling/disabling the relay feature, I think you can use it but not entirely sure. I will have to discuss this with the mesh team and come back to you with an answer on Monday.

[Mttrinh]

Hi,

Peter Gombos said:

What is the recommended way to stop advertisement but remain the member of the mesh?

By "stop advertising" I assume you mean disabling the proxy functionality? You can disable proxy by setting this define MESH_FEATURE_GATT_PROXY_ENABLED to 0.

[Peter Gombos]

Yes, I would like to disable the gatt proxy feature. However I would do it runtime. Compile time define is not suitable for me because I have to use the same firmware in every devices.
How can I enable/disable the proxy functionality at startup?

[Mttrinh]

Hi,

You can use these function to enable/disable proxy functionality during run time: 

proxy_enable() and proxy_disable(), they both call mesh_opt_gatt_proxy_set().

[Peter Gombos]

Hi again!

The recommended proxy related functions work fine in my Rigado BDM-300 module.

However if I use the exactly same firmware on a noname module with the same chip, I have a softdevice assert.

Both type of modules work fine as long as the proxy is enabled. If I disable or stop the proxy from RTT then I get the following assert after couple of seconds: Softdevice assert: 88080:0

The Rigado does not assert and the proxy function disabled fine.

The only difference between the modules is the chip variant. Good is AAE1, bad is AAE0.

(chip is 52832, Mesh v5.0.0, SDK 17.0.2)

Please advise.