Related to Thread cloud coap client and NCP

[Alan Ajit]

Dear nordic,

I have some doubts regarding this both examples. I am new in this thread coap

1. In Thread coap cloud client example uses coap post method is it right?(i think its send coap post request to border router)

2. How this cloud coap client example find the IPV6 address of Border router ?

3. This NCP example i didn't find a Thread Handler to resolve the Thread coap message how this NCP border router works?

                             * where handle the Thread coap post message?

                             *I think this NCP is resolve the Thread Coap post message and send this message to raspberry pi here its sending to cloud am i right?

can you guide me how this client and NCP works?

[Jørgen Holmefjord]

Hi,

1. It is correct that the example use CoAP POST method to update cloud data, but this packet is sent directly to the cloud, not to the Border Router.
2. Thread runs IPv6 natively, and use IPv6 routing mechanisms to send packets to the correct device. The example does not find the IPv6 address of the Border Router, but all nodes in the Thread network are assigned global IPv6 addresses by the border router when this is attached to the network. The border router will create a IPv6 subnet from its own global IPv6 address, meaning that all nodes in the Thread network will know that the border router is where all packets addressed to nodes outside the subnetwork should be directed. The IPv6 address of the cloud service is retrieved using DNS service and URL.
3. The NCP example is a network co-processor, that is used to give the border router Thread connectivity. The NCP does not resolve the messages, only receives and forwards IPv6 packets. When a packet is received by the NCP, it is transferred to the Raspberry Pi through the serialization interface Spinel. The border router forwards the packet from the Thread interface to the Ethernet/WiFi interface without processing/modifying the packet. All happens on IPv6, and the packets are addressed directly to the end-point. Similar the cloud service can address response packets directly to the IPv6 enabled Thread end-device.

I would recommend that you read the documentation for our SDK and the guides on OpenThread.io.

Best regards,
Jørgen