Re: [dnssd] CoAP resource discovery and DNS-SD

Thanks, Ted

Any pointer to Kerry's work in this regard ? I was looking through her expired
draft, but i didn't see anything getting to that exact point
(draft-doi-core-parameter-option looks like related, but i can't really
 make heads or tails out of it).

So lets say:

REQ: GET /.well-known/core?rt=<resource>

     RES: 2.05 Content
     Content-Format: 40
     Payload:
     </b>;rt=<resource>;p=<prio>;w=<weight>;proto=<string>,
     ...

I am just defining in the spec for my resource that it has additional option
link-target attributes. p= for a numeric priority value, w= for a numeric
weight attribute and proto= for a string enumerating protocol details.
And these are the same parameters as what i'd use for the same resource
(oops: service) when using DNS-SD.

It seems as if rfc6690 didn't actually create a registry for those link-targets
but simply created rt= and if= link-targets and just created a registry for
the values of rt= and if=. Which raises the question if i could simply
specify p/w/proto to be normative in the context of the specific resource,
and if not whether those addtiional link-targets would have to be specified as
updated to rfc6690...

Cheers
    Toerless

On Fri, May 13, 2022 at 07:22:41PM -0400, Ted Lemon wrote:
> We were never able to figure that out either. The mapping from Core RD in
> particular to DNS-SD is something that the DNS-SD working group actually
> pursued for a while (Kerry Lynn worked on this pretty heavily for about a
> year).
> 
> On Fri, May 13, 2022 at 7:20 PM Toerless Eckert <tte@cs.fau.de> wrote:
> 
> > 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
> >
> > _______________________________________________
> > dnssd mailing list
> > dnssd@ietf.org
> > https://www.ietf.org/mailman/listinfo/dnssd
> >

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tte@cs.fau.de