[SIPForum-techwg] Comments on 10.1 3 (Route header)

[David Hancock]

John,

Here is some proposed text that attempts to resolve your two comments
below. 

I attempted to write this w.r.t. our reference architecture, where
SIPconnect defines the requirements only for the interface between the
SIP-PBX and SP-SSE, and doesn't say anything about the interfaces
internal to the SP-SSE (for example). Therefore, the SP-SSE requirements
for inclusion of a Route header in out-of-dialog requests sent to the
SIP-PBX on the SIPconnect interface apply only when the SP-SSE receives
a Path header from the SIP-PBX in a REGISTER request. 

These requirements don't apply for the case where the SP-SSE receives a
REGISTER request containing no Path header from the SIP-PBX, but the
SP-SSE decides to add a Path header as the REGISTER traverses internal
proxies on its way the Service Provider registrar. Does this line up
with your/everyone's understanding?

Here's the text...

--------------------------------

17.7	Routing Inbound Requests to the SIP-PBX

If the SP-SSE obtains path vector information from the SIP-PBX during
registration of the Main Public Identity, then the SP-SSE MUST include a
Route header in any out-of-dialog request sent to the SIP-PBX, as
described in RFC 3327. The SP-SSE MUST populate the Route header with
the path vector information received from the SIP-PBX during
registration, and append to it (as the bottom-most Route header entry)
the SIP signaling address of the SIP-PBX. 

    Note, the SIP signaling address of the SIP-PBX is the 
    Contact URI (including any associated URI parameters) 
    that was bound to the called Main Public Identity when 
    the SIP-PBX registered, as described in Section 17.4. 

The path vector information learned by the SP-SSE when the SIP-PBX
registers the Main Public Identity applies to the implicitly registered
Alternate Public Identities as well. Consequently, the SP-SSE MUST
support the Route header requirements defined in this section for
out-of-dialog requests sent to the Main and Alternate Public Identities
of the SIP-PBX. 
 
A SIP-PBX receiving an out-of-dialog request containing a Route header
field MUST ignore the route if the route identifies a local (SIP-PBX)
contact address.

An example of the Route header field is shown below:

Route: sip:outbound.example.net

--------------------------------------

David


> -----Original Message-----
> From: techwg-bounces at sipforum.org [mailto:techwg-bounces at sipforum.org]
On
> Behalf Of Elwell, John
> Sent: Tuesday, April 21, 2009 1:52 AM
> To: techwg at sipforum.org
> Subject: Re: [SIPForum-techwg] Comments on 10.1 3 (Route header)
> 
> 
> 
> > -----Original Message-----
> > From: Elwell, John
> > Sent: 09 April 2009 14:25
> > To: techwg at sipforum.org
> > Subject: Comments on 10.1 3 (Route header)
> >
> > This seems to be solely to do with registration mode, so
> > should it be moved to Annex A?
> >
> > In fact, should there be a sub-section of Annex A on the
> > topic "Routing inbound requests to the SIP-PBX" and should
> > this form part of it? I guess this relates to some existing
> > open issues in 17.4.
> [JRE] I see that this has been partly taken care of in v06. However,
the
> text concerned has been moved to 17.4.2, which is a subsection of 17.4
> (Registration). Since the text deals with INVITE requests (or more
> specifically, new inbound requests), it really doesn't belong there.
It
> probably instead should be a new subsection 17.7 "Routing inbound
> requests to the SIP-PBX", and the words should be generalised to cover
> any inbound request, not just INVITE.
> 
> 
> >
> > In the 3rd paragraph it states:
> > "The SIP signaling address of the SIP-PBX is the Contact
> > address (including any associated URI parameters) that was
> > bound to the called Enterprise Public Identity when the
> > SIP-PBX registered, as described in Section 17.4."
> > Considering that the title of this subsection is "Route
> > header", it is unclear from this wording what the relevance
> > is. Should the contact address be added to the path vector
> > and included in the Route header field?
> [JRE] It is still unclear what is the significance of this paragraph.
> 
> John
> 
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