Iterate through Matter devices on Fabric

[fhfs]

Hello Devzone,

If I'm understanding correctly, if I commission a Matter device onto a Matter fabric.

1. That Matter device should be able to communicate with any device on that fabric?

2. Depending on the privilege in the access control cluster that Matter device can view/operate/manage/administer any device on the fabric?

3. How can I request a list of nodes in the Matter Fabric, from the Matter device? What class/functions do I use on the Nordic Matter Lighting example to view/operate all the nodes in the fabric?

The only examples I have seen are Chip tool controllers that can use discover to find all devices on the fabric.

[Maria Gilje]

Hello,

1. That Matter device should be able to communicate with any device on that fabric?

Yes:

1. For a fabric with a single-network topology the nodes can communicate with any other node through a single network interface. See the Matter 1.1 Core Specification Ch 2.3.1.
2. For a fabric with several peripheral networks, communication is the same as in 1. for nodes in the same peripheral network or through a border router for communication across network boundaries. See Matter 1.1 Core Specification Ch. 2.3.2.

2. Depending on the privilege in the access control cluster that Matter device can view/operate/manage/administer any device on the fabric?

Correct. See more on this in the Access Control Guide.

3. How can I request a list of nodes in the Matter Fabric, from the Matter device?

You can find the different forms of discovery in a Matter fabric in Ch. 4.3 of Matter 1.1 Core Specification. Operational discovery is covered in Ch. 4.3.2

I realize this does not have any information on the actual implementation, so I will contact our developers to ask for specific information about this in NCS.

What class/functions do I use on the Nordic Matter Lighting example to view/operate all the nodes in the fabric?

I will include this when contacting the developers.

Edit: For us to give you the most relevant information please specify which NCS version you are using and if you are using the Matter: Light Switch or Matter: Light Bulb sample.

Best regards,

Maria

[Maria Gilje]

Hello again,

The response from a developer is summarized below.

3. How can I request a list of nodes in the Matter Fabric, from the Matter device?

In general, discovering devices in the same network is done by the DNS entries registered by the nodes and commissioner.

You need a DNS resolver to find the other nodes in the fabric. In NCS you can use the SHELL command matter dns resolve in the connected terminal after including CONFIG_CHIP_LIB_SHELL=y into prj.conf. See Using CLI in nRF Connect examples for more information on the Matter shell commands and usage.

The NCS samples uses binding, which again uses a DNS resolver in a way which is not visible for the user. So the node ID is not discoverable for the user in the default NCS samples.

What class/functions do I use on the Nordic Matter Lighting example to view/operate all the nodes in the fabric?

You can modify the sample to include a DNS resolver by adding the methods of Dnssd::ResolverProxy from the SHELL command implementation for DNS resolver (NCS v2.5.1) .

Best regards,

Maria

[fhfs]

Thank you for your response, I have some reading to do!