Subject: Re: [sipcore] #38: How is the mapping of a GRUU into its UA Contact marked?

From: Mary Barnes <[email-masked]>
Date: Wed, 13 Oct 2010 15:03:44 -0500

Dale,

So, then it seems you are advocating we add an additional "gr" tag.
However, wouldn't the absence of "mp" or "rc" for a GRUU indicate that
the GRUU wasn't mapped.  I guess it is not harmful to add a unique tag
for cases where a GRUU is used, but do you have a use case where this
is relevant?

Thanks,
Mary.

On Tue, Sep 7, 2010 at 12:32 PM, Worley, Dale R (Dale)
<[email-masked]> wrote:
> ________________________________________
> From: Shida Schubert [[email-masked]]
>
> I guess we could but is it really necessary when "gr" tag is present for GRUU?
> _______________________________________________
>
> That's a possibility.  But just because the mapped-from URI is a GRUU doesn't mean that the mapped-to URI was done by looking up the GRUU's binding -- there may be some other mapping mechanism that is involved.
>
> Dale
> _______________________________________________
> sipcore mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/sipcore
>

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From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Thu, 21 Oct 2010 16:08:35 -0400

________________________________________
From: Mary Barnes [[email-masked]]

I haven't thought through all the use cases.  I've just been assuming that the goal is for each conversion of one URI into another to describe the nature of the conversion.  I expect the case of a GRUU being converted into its registered contact to be frequent, and there is the possibility that in some situations GRUUs will be converted into URIs some other way.  So it seems to me to be reasonable that there is a tag meaning "the mapping of a GRUU into its registered contact".

Perhaps an explanation of the organizing principle of the set of tags would make clearer why some conversions have tags and others do not.

Dale

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From: Mary Barnes <[email-masked]>
Date: Fri, 22 Oct 2010 13:54:36 -0500

Hi Dale,

Responses inline below [MB].

Mary.

[MB] The question Shida raised earlier was why would you need this tag
when you have the "gr" tag in the URI and you have the "rc" tag in the
History-Info entry.  The question to me is to whom does it matter that
it was a GRUU that was mapped to a registered contact.  There is a
gruu use case in the call flows describing this.  [/MB]

> Perhaps an explanation of the organizing principle of the set of tags would make clearer why some conversions have tags and others do not.
[MB] That might help. The reason there are just the two tags was
because those were the ones that came out of the use cases. We
originally had all entries tagged and the pushback was that the other
tags were not necessary (at least for the use cases envisioned). For
example, there was a "noop" for next hop forwarding, a "predetermined"
for things like the Request-URI containing a maddr, strict routing,
etc. and the "rc"s were divided into two categories - normal
registered contacts and registered aliases.   In the end, it was only
the "rc" and "mp" that seemed to be relevant for most applications,
although one could debate that the others might help with debug. [/MB]