When someone is calling the AOR, it will be replaced with the registered
contact. Does it matter is someone else registered the contact/AOR? The
call is not for that someone.

Regards,

Christer

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Mary Barnes
Sent: Saturday, March 14, 2009 4:47 PM
To: Hans Erik van Elburg; [email protected]
Subject: Re: [Sip] Issue 3 - two tags
(wasRE:I-DACTION:draft-rosenberg-sip-target-uri-delivery-01.txt

Correct, you don't know anything about the URI that overwrites the
request-URI.   BUT, you know the type of URI that was overwritten (with
respect to how it is used at the incoming Proxy). You know that the
request URI that was overwritten was one of the types we've been
discussing - i.e., a URI that can be used for a service Lookup in a
Registrar, whether that URI is mapped, configured, etc. or whether that
URI is just for a proxy hop - i.e., it's not a URI for which the proxy
is responsible. And, you are using that tag against the URI that is
being overwritten.
 
Mary. 

________________________________

From: [email protected] [mailto:[email protected]] On Behalf Of
Hans Erik van Elburg
Sent: Saturday, March 14, 2009 2:55 AM
To: [email protected] List
Subject: Re: [Sip] Issue 3 - two tags (was
RE:I-DACTION:draft-rosenberg-sip-target-uri-delivery-01.txt


I just realised that there is an additional problem that makes it even
harder to do any distinction.

A UA may register as a contact an AOR of another user or resource.
Effectively this causes the request to be forwarded to the other user by
overwriting the Request-URI.

So the fact that the Request-URI was overwritten due to a location
lookup, doesn't tell you a bit about the nature of the rewrite.

/Hans Erik van Elburg



On Fri, Mar 13, 2009 at 10:53 PM, Mary Barnes <[email protected]>
wrote:


        Responses below [MB].
        
        ________________________________
        

        From: Hans Erik van Elburg [mailto:[email protected]]
        
        Sent: Friday, March 13, 2009 4:17 PM
        
        To: Barnes, Mary (RICH2:AR00)
        
        Cc: Elwell, John; [email protected]
        
        Subject: Re: [Sip] Issue 3 - two tags (was RE:
        I-DACTION:draft-rosenberg-sip-target-uri-delivery-01.txt
        
        
        
        I guess you mean that you agree with John that such rule can not
be
        reliably construed.
        
        [MB] Which rule?  I fully agree we can discern the 3 cases as I
        explained below. Per 16.5 (Determining Request Targets) in RFC
3261,
        these are unique and recognized situations. The reason I refer
to loose
        routing is that it's my understanding it is far more commonly
used and
        RFC 3261 doesn't even describe strict routing - it focuses on
loose
        routing and strict routing support is for 2543 backwards
compatibility
        as I understood. But, actually it makes no difference to
History-Info
        processing.  The important thing really, is that you MUST tag
the old
        entry as you are doing the processing per 16.5 as that
information is
        lost by the time you get around to adding the next History-Info
header
        in section 16.6 ( Request Forwarding). I think one thing that
might be
        being missed in this thread is that I have been very careful to
rely
        explicitly on what is described in 16.5 - that a must read to
understand
        what I am saying - again there is a lack of clarity in that
section and
        we can suggest clarifications once we all can finally agree
appropriate
        terms. If you'd like me to pull the explicit text that supports
        everything I've been saying, I can do so, but it's somewhat a
waste of
        time. [/MB]
        

        I dont think I have seen convincing proof that such is the case.
        
        [MB] And, I'm not saying that you can't construct such a rule -
indeed I
        am saying that you certainly should be able to per RFC 3261
section
        16.5.  Can you point out what text below that suggests I am
saying that?
        [/MB]
        

        Are you also saying that we may only consider loose routing
being used?
        
        [MB] Nope. [/MB]
        

        Further for "configured mappings" for which we never saw a
proper
        definition. But assuming that this is a proxy that can be
configured to
        do a Request-URI  rewrite based on some configured setting.
        
        [MB] The concept of "configured mappings" is described in RFC
3261 -
        perhaps not with the level of granularity or specificity that
some might
        desire, but it's there - it's initially described as an abstract
        location service (1st Paragraph section 16.5).  And, then later
it
        specifies that a proxy can determine "targets" (3261 term not
mine) just
        about any ole way it wants, so I don't know that we need to
define a new
        term for "configured mappings" per se - there is no limitation
as to the
        mechanism one can use to determine the request-URI for the
outgoing
        request (once it is determined that the Proxy is ALLOWED  to
overwrite
        the request-URI - the right domain, etc.),  This is a
fundamental SIP
        concept that many products use to give a (human) user
flexibility in
        configuring where an incoming call might terminate. So, I see no
issue
        at all is specifying two tags to capture this rewrite as it's
already in
        section 16.5 that this is information that a Proxy should be
able to
        derive. [/MB]
        

        In that case there are two variants of such mapping:
        1. A mapping that changes the identity of the target to be
reached.
        (This is what call forwarding or diversion does normally.)
        2. A mapping that only changes  the next hop route taken towards
the
        target identity that has not been changed.
        
        For the UAS it only matters that the home domain does the
tagging
        consistently and correctly if it wants to rely on such
information.
        
        [MB] I don't know that I agree it's the home domain - it's a
proxy that
        has responsibility for the domain in the request-URI that is
able to do
        the service lookup or using any other sort of mapping to
determine the
        new URI for the request-URI in the outgoing request.  I don't
know that
        we want to restrict that to the "home" domain. If we restrict it
to the
        home domain, then that implies that we are only tagging the
entries that
        are determined based on service lookup in a Registrar (per RFC
3261's
        definition of a "home domain").  [/MB]
        

        Otherwise we would have to start adding information about the
domain
        that added a specific hi-entry, if one wants to be sure who
added the
        particular hi-entry.
        
        [MB] I'm not sure why this would be needed and I wasn't
espousing that
        it would - we know by definition that the domain that mucked
with a URI
        is the domain associated with the URI that was overwritten/lost,
etc.
        [/MB]
        

        /Hans Erik van Elburg
        
        
        
                ---remainder of theread snipped by Mary. --------
        


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