Yeah I like STUD because it's explicit.
But the big difference I see is what happens if R1 supports STUD but P2, or 
more likely a domain between P2 and P3, Retarget but don't support STUD.  Then 
R2 gets a Target which is wrong - it's the URI of C vs. D (or something between 
D).  In other words it could be the target uri of a completely different 
user/domain.

With UALR, since retargeting proxies already replace the req-uri today, you'd 
get a req-uri which isn't wrong.  Even if P2 did Rerouting and not UALR (ie, 
still replaced the req-uri but was not really retargeting), the req-uri 
received by R2 wouldn't be totally wrong.  It would lose the parameters and 
info that could have been useful, but it's less likely to cause harm. (maybe?)

The counter-argument is what happens if P3 doesn't do UALR, but I would think 
it's far more likely that an operator of a domain has control over the 
equipment in their domain.

Though I'm probably thinking in circles - this whole topic makes my head hurt.  
:)

-hadriel

> -----Original Message-----
> From: Elwell, John [mailto:[EMAIL PROTECTED]
> Sent: Friday, January 18, 2008 10:28 AM
> To: Hadriel Kaplan; Dean Willis; IETF SIP List
> Subject: RE: [Sip] Vocabulary and problem statement forRequest-
> URI,retargeting, and SIP routing (long, but read it!)
>
> Hadriel,
>
> Well, I have been having a side thread with Christer and Hans Erik, and
> the only difference other than syntax that they could convince me of was
> support for UAs that do not register, in that with loose-route you would
> need additional provisioning in the domain proxy to say that the UA
> (gateway or whatever) supports loose-route. Given that you would need
> provisioning in the proxy anyway for such UAs, I didn't see this as a
> big deal, but it is a difference.
>
> John
>
> > -----Original Message-----
> > From: Hadriel Kaplan [mailto:[EMAIL PROTECTED]
> > Sent: 18 January 2008 15:15
> > To: Elwell, John; Dean Willis; IETF SIP List
> > Subject: RE: [Sip] Vocabulary and problem statement
> > forRequest-URI,retargeting, and SIP routing (long, but read it!)
> >
> > Hey John,
> > Inline...
> >
> > > -----Original Message-----
> > > From: Elwell, John [mailto:[EMAIL PROTECTED]
> > > Sent: Friday, January 18, 2008 2:48 AM
> > > >
> > > > But in the re-targeting scenario such as:
> > > >                     RTRG                    RRT
> > > >                    +---+                   +---+
> > > >                    |R1 |                   |R2 |
> > > >                 B /+---+\ C             E /+---+\ F
> > > >             RT   /       \  RT      RT   /       \  RT
> > > >            +---+/         \+---+ D +---+/         \+---+
> > > >            |P1 |           |P2 +---+P3 |           |P4 |
> > > >         A /+---+           +---+   +---+           +---+\ G
> > > >          /                                               \
> > > >    +---+/                                                 \+---+
> > > >    |UAC|                                                   |UAS|
> > > >    +---+                                                   +---+
> > > >
> > > > UA-Loose-routing wants the req-uri seen on connection "C" I think.
> > > > To header gives you A.
> > > > PCPID gives you E.
> > > > Hist-Info gives you A,B,C,D,E,F.
> > > [JRE] According to Dean's definition of RT, it does not change the
> > > Request-URI (only the Route header field presumably, or
> > maybe not even
> > > that).
> > > So C, D and E are the same. Also A and B are the same, and
> > F and G are
> > > the same.
> > > So I think:
> > > - UA-Loose-routing gives you C/D/E
> > > - To gives you A/B
> > > - PCPID gives you C/D/E
> > > - Target gives you C/D/E
> > > - Hist-info gives you A/B, C/D/E and F/G.
> >
> > Yes, I agree that is the *theory*.  :)
> > I drew it that way though so we could argue about what the
> > UAS/UALR-draft _wants_ to happen vs. what _will_ happen if P2
> > or P3 are not purely RT's and didn't support a new draft.
> > (Since it seemed the conversation was going that way
> > previously on this list, for example when Christer pointed
> > out the difference between Target and PCPID)
> >
> > For example, I think there is more than just a syntax
> > difference between Christer's sip-target-uri-delivery draft
> > (STUD?) and Jonathan's UALR approach.  Though I have no idea
> > which one is better.
> >
> > -hadriel
> >
> >
> >
> > _______________________________________________
> > Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
> > This list is for NEW development of the core SIP Protocol
> > Use [EMAIL PROTECTED] for questions on current sip
> > Use [EMAIL PROTECTED] for new developments on the application of sip
> >


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