[SIPForum-techwg] Question re Application Server

[Chris Sibley]

Hi Hadriel,

Comments inline below..

Thanks,

--Chris

> -----Original Message-----
> From: Hadriel Kaplan [mailto:HKaplan at acmepacket.com]
> Sent: Friday, September 08, 2006 3:53 PM
> To: 'Chris Sibley'; 'Paul Kyzivat'; 'SIP Forum Tech WG'
> Subject: RE: [SIPForum-techwg] Question re Application Server
> 
> Hi Chris,
> Inline...
> 
> > -----Original Message-----
> > From: Chris Sibley [mailto:Chris.Sibley at cbeyond.net]
> >
> > I agree that we need to limit scope, but the points that Paul brought up
> > are hard to ignore. If we don't at least cover the
> > Enterprise<-->Enterprise scenario then I think we would have a serious
> > functionality deficiency given the way the text currently reads (i.e.
> > the SP couldn't route calls between two Enterprises that it services
> > without being a B2BUA.)
> 
> Yup, and the part that creates the problem is the doc specifies what the
> To/From MUST look like when coming from the SP.  We don't have to cover
> any
> specific "scenario" if we just say something like: "This section specifies
> what the To/From MUST look like for PSTN-originated calls from the Service
> Provider.  The To and From headers may be different from those specified,
> for other call path scenarios.  For example, the requests may not come
> from
> an Application Server at all, but rather through Proxies.  A PBX MUST be
> capable of using the Request-URI as the target identifier and not the
> To-URI."  Or something like that.
> 
> 

Actually, I think there is considerable value in defining what the 'To:' and
'From:' fields will look like when coming from the SP. The whole point of
this specification is to define a "profile" of SIP that can be used to
accomplish a specific function, PSTN interconnection. If we restrict
ourselves to only defining rules for the Request URI then IMO we
significantly "water down" the spec. 

At the very least, I think it is very important for the PBX to know in
advance what URIs will look like in the 'From:' field so that they will have
a predictable format that can be used to properly deliver calling number
and/or name identification to the callee. Knowing in advance that an E.164
address will be present in this field is highly useful for delivering that
feature. I'm pretty sure it would also be useful for a myriad of other
traditional PBX features.

> > I'm not sure what you meant by consumer/subscriber. Would this class of
> > user really be fundamentally different enough to warrant different URI
> > formatting conventions?
> 
> Yup.  They don't have to be e164 sources at all. (and of course neither do
> "Enterprise" sources) And the parameters can be different.
> 
> -hadriel
> 

Again, since this is a profile of SIP for PSTN interconnection why would we
want to use non-E.164 addresses and/or different parameters for these users?
What are the critical factors that would drive the need for them to behave
differently (in the scope of PSTN interconnection)?