> -----Original Message-----
> From: Doug Hurtig [mailto:[EMAIL PROTECTED]]
> Sent: Monday, March 26, 2001 10:09 AM
> To: Christer Holmberg
> Cc: [EMAIL PROTECTED]
> Subject: [Sip-implementors] Re: contact headers
>
>
> Thanks,
>
> Not sure about the Contact header. The 2543 document uses
> the 1#(name-addr | addr-spec)... syntax which implies that
> a contact header can contain at least 1 but optionally multiple
> addresses.
>
> Do you remember where you saw the restriction on the number
> of contacts that may be in a given method, particularly the invite
> method?
Unfortunately, Contact conveys two different things, depending on the
message. In INVITE, 200 to INVITE, it means "this is the address for
subsequent signaling". For redirects and registers, its "here is a list of
places to try". For INVITE and 200 OK to IVNITE, there *MUST* be only a
single URI, and it *MUST* be a sip URL. For registrations (and registration
responses, of course), and redirects, it can be any number. Rule of thumb:
if the Contact is used to build a route header, there better be just one,
and it better be a SIP URL. Thats because the contact URI in this case is
used for explicit addressing, not naming, and it has to be recognized by all
proxies. Since the purpose here is addressing and not naming, a URI which
really represents a name, such as a tel URI, makes no sense.
We'll clarify this.
-Jonathan R.
>
> Christer Holmberg wrote:
>
> > Hi Doug,
> >
> > Doug Hurtig wrote:
> > >
> > >Christer,
> > >
> > >Below you suggest that multiple contacts headers should
> > >be allowd in an invite. I have assumed that an invite can
> > >already have multiple contact records. Is this not true?
> >
> > My understanding was that it is not. Maybe this has
> changed, so I guess
> > it's better to verify it :)
> >
> > >I sent the original message just to find out if it would
> > >be a problem when I received a URI as a telephone number,
> > >if it would be allowed to send my response with SIP URIs.
> >
> > First, I don't think that's a good idea. I would be very telephone
> > number specific, and it could cause mapping problems somewhere.
> >
> > Second, I don't see the idea of using tel-urls in the first place :)
> > Everything you can do with a tel-url you can do with a sip-url. Or?
> >
> > Regards,
> >
> > Christer Holmberg
> > Ericsson Finland
> >
> > >
> > > If there are multiple contact headers, then I assume that all
> > > of them would be copied to the route header.
> > >
> > >
> > > Doug
> > >
> > >
> > > > Hi Jon,
> > > >
> > > > First a comment on the thread in general.
> > > >
> > > > It's true that a tel-url can be mapped into a sip-url,
> but do we really
> > > > solve a problem by allowing only sip-url and tel-url in
> the Contact
> > > > header? Sure, this would solve the problem when we talk
> about telephone
> > > > numbers, but isn't the whole idea of what we are doing
> to finally go
> > > > "beyond" that?
> > > >
> > > > >My original mail on this subject was intended to refer
> only to UA call
> > > > >set-up behavior (the subject that kicked off this
> thread); bis 2.2
> > > > >explicitly forbids non-SIP URIs in the Contact headers
> of INVITE,
> > OPTIONS,
> > > > >BYE, and 2xx messages, -not- 3xx messages nor
> REGISTER. Sorry for my
> > lapse
> > > > >of precision; didn't mean to start a panic here.
> > > >
> > > > I think the proposal I wrote in my other mail (by specifying the
> > > > supported URI in an Accept-XXX header) would solve also
> this. In my
> > > > initial INVITE I add a Contact with ANY URI, and if the receiver
> > doesn't
> > > > support it he will send some 4xx response, and a header
> indicating
> > which
> > > > URIs he supports. An idea could be to even allow
> multiple Contacts, all
> > > > with different URIs, in the INVITE, and the UAS can
> choose the one he
> > > > wants and/or supports...
> > > >
> > > >
> > > > Regards,
> > > >
> > > > Christer Holmberg
> > > > Ericsson Finland
> > > >
> > > Regards,
> > > Doug Hurtig
> > >
> > > Tekelec
> > > 2425 N. Central Expressway
> > > Richardson, Texas 75080
> > >
> > > [EMAIL PROTECTED]
> > > 972.301.1203
> > >
> > (See attached file: christer.holmberg.vcf)
>
> --
> Regards,
> Doug Hurtig
>
> Tekelec
> 2425 N. Central Expressway
> Richardson, Texas 75080
>
> [EMAIL PROTECTED]
> 972.301.1203
>
>
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---
Jonathan D. Rosenberg 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.cs.columbia.edu/~jdrosen PHONE: (973) 952-5000
http://www.dynamicsoft.com
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