Matter; Chip controller and OTBR communication

RE: Matter; Chip controller and OTBR communication

AHaug — Mon, 01 Aug 2022 13:37:41 GMT

Hi,

[quote user="alvin7"]Where do i get the matter specification?[/quote]

You will have to be a member of the Matter Working Group to get access to the specification and I would recommend you ask the Connectivity Standard Alliance for which type of membership that would be (see https://csa-iot.org/ for more).

[quote user="alvin7"]I want to control the matter device globally using MQTT in the border router, is there a sample code available or any documentation for said purpose?[/quote]

Unfortunately we do not have any sample codes for that. As far as Matter and MQTT goes, they are unrelated tehcnologies so someone would need to implement a bridge device to combine those two.

Kind regards,
Andreas

RE: Matter; Chip controller and OTBR communication

alvin7 — Mon, 01 Aug 2022 05:27:12 GMT

Hi, I apologize for the late reply. Thanks a lot for your response. I have a couple more queries to fill up

Where do i get the matter specification?
I want to control the matter device globally using MQTT in the border router, is there a sample code available or any documentation for said purpose?

Thank you in advance.

RE: Matter; Chip controller and OTBR communication

AHaug — Thu, 28 Jul 2022 12:58:27 GMT

Hi,

My colleagues in our Matter team explained it to me as follows:

The protocol stack used for sending Matter commands is: [15.4/WiFi/Ethernet] / IPv6 / UDP/ Matter Message
- Communication between the controller and OTBR happens over WiFi/Etherhet and further within a Thread network over Thread/15.4.
- Matter Message is a generic message format used for all communication initiated or received by a Matter node. For example, for messages used to establish a secure channel, and messages used to encode Matter commands.
Matter Message format is described in the Matter specification which we're not allowed to distribute. If you have access to the specification we can point to the specific chapter. Note that Matter Message format is used for multiple purposes and sending ZCL commands is just one of them, i.e. they use a specific Message Type in the Matter Message. ZCL commands themselves are encoded using a Matter TLV encoding which is also described in the specification.
When you type "zcl" command a specific ZCL command (or "action" I should have said to use Matter's nomenclature) is encoded using the Matter TLV format, then it put in a Matter Message and sent using a UDP socket. If this is the first communication with a given node, before the packet is actually sent the controller must find an IP/UDP address of the node using DNS-SD and establish a secure session with the node using Matter-specific Certificate-Authenticated Session Establishment protocol.

I hope this answers your questions!

Kind regards,
Andreas