Re: Is GRUU generated in the case of registration with instance-ID and reg-ID

Hi Christer,

Christer Holmberg wrote:
> Hi Michael, 
> I think it is confusing that the 200 OK does not contain the gruu.
> Shouldn't the 200 OK contain all currently registered contacts?
>   

Yes, the 200 OK should contain all currently registered contacts, but a
GRUU isn't a registered contact.  When the UA indicates support, the
GRUUs are returned as header parameters to their associated contact, not
as separate contacts.

> When a contact has been registered for an AOR (the RFC3680 statemachine
> for the AOR is in "active" state), meaning that the AOR is reachable.
>
> So, what is the justification for generating a gruu, but not returning
> it (after all, the gruu will be sent to the UA if it registers to the
> regevent package, so...)??? 
>   

Sending a header parameter to a UA that doesn't declare it supports it
seems to be inviting interop issues.  I suspect this is the reason,
although I wasn't involved with that decision so I can't say
categorically what the reason was.

> My question is still: if the REGISTER contains instance-id AND
> Require:gruu, is a gruu generated?
>
> On one side the presence of instance-id always creates a gruu, but on
> the other side the text says that the precense of Require:gruu does NOT
> mandate the creation of a gruu.
>
> OR, does the text simply mean that Require:gruu on its own (ie no
> instance-id) does not mandate the creation of a gruu?
>   

I think it is this last one.  'Require: gruu' has no special meaning to
a gruu-supporting registrar - it only prevents non-supporting registrars
from handling the request. 

A gruu-supporting registrar will follow section 5, which contains the
phrase:
"If there is no valid public GRUU, the registrar SHOULD construct a
public GRUU"

Assuming the UA includes a +sip.instance, and doesn't try to do anything
silly (register the AoR as a contact, register a gruu as a contact),
then you SHOULD get a GRUU made for you.

> I don't remember the exact details, but: 3GPP uses gruu, and 3GPP has
> adopted outbound for the multiple registration feature (previously it
> was defined only for NAT traveral), so the question came up when the
> procedures for the multiple registration feature was discussed: will a
> gruu also be generated?
>
> It may be obvious to people on this list, and of course we could clarify
> it in the 3GPP specifications. But, I think this would be a useful
> generic clarification in the outbound spec.
>   

Maybe someone else would like to address this point.  Personally, I am
ambivalent.

> Regards,
>
> Christer
>   

Regards,

Michael

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