Re: [Sip] Vocabulary and problem statement forRequest-URI, retargeting, and SIP routing (long, but read it!)

[Paul Kyzivat <[e-mail]>]

Elwell, John wrote:

> [JRE] And also, P2 should be just routing on the Route header field,
> because there is still something in the stack. So it would have to be a
> misbehaving proxy to get it wrong.

I had always assumed that as long as there was something in the Route 
stack the R-URI would be left alone.

But if you read 3261 carefully it nowhere says that. The rules for doing 
translations on the R-URI (if you are responsible for it) are 
independent of the routing rules. So it seems valid (maybe mandatory, 
though that isn't clear to me) that you might translate the R-URI even 
though there is a Route header, and *then* route based on the Route header.

	Paul

> But in any case, I thought UALR was meant to be applied only on the last
> hop (or the last set of hops) from the domain proxy to the UAS, so once
> you invoke it there should not be any more retargeting or rerouting
> proxies on the path. Maybe the domain proxy is never able to be certain
> of this.
> 
> John
> 
>> Though I'm probably thinking in circles - this whole topic 
>> makes my head hurt.  :)
>>
>> -hadriel
>>
>>> -----Original Message-----
>>> From: Elwell, John [mailto:[e-mail]]
>>> 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:[e-mail]]
>>>> 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:[e-mail]]
>>>>> 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
>>>>
>>>>
>>>>
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> 
> 
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