Hi,
I am a bit behind on this so forgive my ignorance, comments inline
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of
> Paul Kyzivat
> Sent: 12 October 2001 16:22
> To: [EMAIL PROTECTED]
> Subject: [Sip-implementors] Re: Need clarification on callerprefs
>
>
> I have another question about callerprefs, in addition to
> the earlier
> messages I have posted on this subject. This is primarily a question
> about the handling of REGISTER by a registrar, but the question only
> makes sense in the context of the changes to the Contact
> header proposed
> in draft-ietf-sip-callerprefs-04.
>
> Section 5.1 says: "This specification adds the following extension
> parameters to the Contact header field ... These parameters
> apply to a
> single URI. When used in a Contact header, they specify
> characteristics
> of the URI in the header."
>
> Now, suppose I want to specify that a given URI is fully capable in
> English and slightly capable in Spanish. This is a
> reasonable thing to
> want to specify, and there seems to be a way to do it:
>
> Contact: sip:[EMAIL PROTECTED]; language="en"; q=1.0,
> sip:[EMAIL PROTECTED]; language="es"; q=0.2
I don't really follow what you are trying to do here, the above
registration will route both Spanish and English requests to the the
same location. Surely a more common registration would be
Contact: sip:[EMAIL PROTECTED]; language="en"; q=1.0,
sip:[EMAIL PROTECTED]; language="es"; q=0.2
all your concerns are based around the fact you want to route to the
same URI, if joe can handle both English and Spanish at the same
location what's the problem.
> My question is: is this a legal construction in a Contact header?
> Normally, if there had been a prior registration of
>
> Contact: sip:[EMAIL PROTECTED]; language="en"; q=1.0
>
> and a new registration was received containing
>
> Contact: sip:[EMAIL PROTECTED]; language="es"; q=0.2
>
> then the new contact would *replace* the old one. As far as
> I can tell,
> the bis is silent on what should happen if two contacts
> with the same
> URI are present in the same register request. I can see
> three possible
> interpretations:
>
> 1) upon receipt of the REGISTER request, the registrar
> first removes any
> previously registered contact entries that match any of the contact
> entries in this REGISTER request. Then all the contact
> entries in this
> register request are saved.
>
> 2) a REGISTER request with multiple contact entries is
> processed much
> like multiple REGISTER requests each with a single contact
> entry. If two
> contact entries mention the same URI, each one in turn replaces the
> previous one. Only the last remains. No error occurs.
>
> 3) a REGISTER request with multiple contact entries
> containing the same
> URI is considered erroneous, and results in an error such as 400 Bad
> Request.
>
> Of these, (1) is compatible with the example above while the others
> aren't. (2) is a silly interpretation - it is never useful.
> (3) forbids
> a useful application and is extra work to detect.
I'd go with 2 here and agree it's a silly interpretation, but add it
was also a silly request and clarify the situation in the 200 Okay.
James
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