RE: Openthread SED multicast

Øyvind — Wed, 31 Mar 2021 13:22:48 GMT

Hello Farhang,

I needed to confer with our OpenThread experts.

Question 1 - SEDs do no receive the ff03::1 multicast messages by design. There are different multicast addresses that are used by SEDs. From Thread 1.1 Spec - Chapter 5.2.3.2:

You should be able to use the following addresses:

ff33:40:fde2:3960:66dd::1
ff32:40:fde2:3960:66dd::1

These are Link-Local All Thread Nodes and Mesh-Local All Thread Nodes addresses. For more information, please see RFC3306 - Unicast-Prefix-based IPv6 Multicast Addresses.

Question 2 - If the board board was programmed from FTD to MTD FW and the persistent storage has not been cleared, you may observe issues similar to that. Then flashing the device, make sure to use:

west flash --erase

Question 3 - The Zephyr CoAP API implementation is simpler than OpenThread. In Zephyr's case the CoAP implementation will prepare the frame, but you will need to send it yourself. Also retransmissions are not handled automatically. There are plans to port the CoAP server, however, I have no timeline for this I'm afraid.

Please note that the following days are Easter holidays in Norway and one must expect a delayed answer due to short staff in the Technical Support team.

Kind regards,
Øyvind