Multicasting a message with secure coap in openthread

[Sunidhi Dixit]

So I did the exercise with the 3 thread k32w dongles

On device-1

> coaps start

> coaps psk 1 1

** the ipaddr for device-1 is fe80:0:0:0:3c0b:f8c0:7744:6d86

On device-2

> coaps start

> coaps psk 1 1

> coaps connect fe80:0:0:0:3c0b:f8c0:7744:6d86

after this I got the message of coap connected

but when I tried the same steps on device-3

> coaps start

> coaps psk 1 1

> coaps connect fe80:0:0:0:3c0b:f8c0:7744:6d86

The coap session was not connected.

How can I multicast/broadcast a secure coap message on multiple devices?

Thanks in advance.

[Stuart Longland]

On Tue, 21 Dec 2021 10:27:34 -0800 (PST)
"'Sunidhi Dixit' via openthread-users" <openthre...@googlegroups.com> wrote:

> How can I multicast/broadcast a secure coap message on multiple devices?

I don't think dTLS over multicast is even possible at this time.
Secure CoAP is built upon dTLS.

There is a draft RFC on the topic:
https://datatracker.ietf.org/doc/html/draft-lucas-dtls-multicast-00

It expired in 2018.
--
Stuart Longland (aka Redhatter, VK4MSL)

I haven't lost my mind...
...it's backed up on a tape somewhere.