How does the reliable broradcast message to multiple nodes in a mesh network works?

[khozDonel]

Hello Devzone,

I want to send a group message in light_switch example , I know that the group message is using the non-reliable type of message sending, could you please let me know if it is possible to use reliable type of message transmission to a group address and how would be the behaviour , do we get any collision as all the nodes are trying to respond with acknowledgement?

Thank you!

[MartinBL]

Hi,

There is really no thing such as reliable messaging to a group in the BLE mesh. The problem is that a random device can't know how many nodes there are in a given group. So, what we do is to increase the number of retransmissions

There is an API used by some models called access_reliable_publish(), but that one is sort of lying about the reliability aspect. It will repeat the access message until it gets a response if the message is destined to a unicast address, otherwise it will repeat it until a set timeout is reached