RE: how contol certain number of specific devices who config server with a PHONE

Hik — Fri, 15 Sep 2023 13:31:29 GMT

Consider time limit，send message to each address is not very good for me,I will think about how to build a custom model.

Many thanks for sharing

RE: how contol certain number of specific devices who config server with a PHONE

tesc — Fri, 15 Sep 2023 13:06:15 GMT

Hi,

[quote user=""]Is there a way control a certain number of specific devices with a smart phone dynamically[/quote]

Messages are typically addressed either to unicast addresses or group addresses. The group address subscriptions are more or less fixed. (You can configure group subscription, but it requires a few messages back and forth, so you would only do so if the same set of nodes should be addressed several times in that configuration.)

If you have a large number of nodes, and only a subset of those nodes should get a message, there are a few scenarios:

A. It is the same subset every time -> Use a group address, all nodes in the subset subscribes to that node.

B. It is always one of a small number of subsets (that may or may not overlap. -> Use group addresses, one for each combination.

C. It is a new subset every time. (I.e. the selection of nodes looks random.) -> The easiest way to implement this is to simply send one unicast message to each node in the subset. This will take some time, though, since there is a restriction of maximum 100 network packets originating from a node per 10 second sliding window. This is in the Bluetooth mesh specification. There is also a technical limit to the throughput when a node sends (or relays) a series of messages.

Maybe, for C, one option you could investigate could be to use a custom model, where the message contains an additional payload which is a bitmap for flagging which nodes should act on the message. Then you could use a group message, to send the same message to all nodes, and implement the model such that the nodes will ignore or act on the main contents of the message based on their corresponding bit in the bitmap. Alternatively, consider having multiple groups like that, and to address multiple devices you send one message to each group, each containing both the main message and the bitmap for the corresponding group. For this you would probably need a custom way to configure the node with which bit (and group) the node corresponds to. Please note that everything suggested in this paragraph is nothing more than ideas, which may or may not work in practice, and which we haven't tested nor scrutinized.

Maybe, for C, depending on the use case, there may be other schemes that will let you address the proper subsets without needing to address each node individually.

The simplest solution, however, if your throughput and timing constraints allow it, is to address each node individually. This way you will be able to address 10 nodes per second on average, or lower if you have message retransmits.

Regards,
Terje