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[core] CoAP resource discovery and DNS-SD

Toerless Eckert <tte@cs.fau.de> Fri, 13 May 2022 23:20 UTC

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Date: Sat, 14 May 2022 01:19:57 +0200
From: Toerless Eckert <tte@cs.fau.de>
To: core@ietf.org
Cc: dnssd@ietf.org
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Subject: [core] CoAP resource discovery and DNS-SD
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Dear CoAP WG

I am trying to figure out how to use CoAP discovery as specified in RFC7252
(and expanded in rfc6690 and rfc7390),  but i can not figure out how
one would encode basic parameters of a resource, such as those supported
in DNS-SD, rfc6763:

When discovering more than one instance of a resource, such as possible,
when using multicast discovery as on rfc7252, clients will have to figure out,
which instance of a resource to select. DNS-SSD has priority and weight
parameters associated with each instance. How would one describe/encode
such instance and weight ?

When discovering one or more instance via DNS-SD, the discoering client
may further select the best instance in terms of interoperability, functionality
and performance based on one or more key=value property pairs describing
the instance. How is this done in CoAP ?

Thanks a lot!

Toerless

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