Subject: RE: [AAA-WG]: Re: Comments: draft-belinchon-aaa-diameter-mm-app-0 1.txt

From: "Daniel Warren" <[email-masked]>
Date: Wed, 9 Jul 2003 16:49:30 +0100

I think I might (although I also think someone in your office probably could
tell you too!!).

The fundamental difference in usage I think is that the UAR is generally
used for REGISTER because the SIP Server is the one on the call originating
side, so when a user registers, it is the UAR that is sent to the Diameter
Server to obtain the S-CSCF details and/or capabilities for the subscriber
and ultimately to faciliate the registration of that subscriber with the
network.  LIR is used on a session terminating SIP Server to contact the
Diameter Server for the location of the subscriber but does not involve the
subscriber explicitly registering with the network as a consequence.

I can't remember much more of the detailed rationale for why we ended up
with two commands rather than one, and I am not entirely convinced that this
explanation justifies it.

I'll keep thinking about it.

Dan

-----Original Message-----
From: Miguel A. Garcia [mailto:[email-masked]] 
Sent: 09 July 2003 13:10
To: Warren, Daniel [MOP:EP10:EXCH]
Cc: [email-masked]
Subject: Re: [AAA-WG]: Re: Comments: draft-belinchon-aaa-diameter-mm-app-0
1.txt

Hi Dan:

You are opening the floor for an interesting discussion. I had the same 
sort of concerns about the similarities between UAR and LIR.

The fact that UAR is triggered from a SIP REGISTER and LIR is triggered 
from any other SIP request is not enough to justify two different commands.

I would then ask you what is the reason to have two different commands. Why 
is not possible to have a single command? Do you know the answer?

/Miguel

Daniel Warren wrote:
> Another comment (or maybe it's a question).  In section 3.3, there is
> text that says...
> 
> 'Although the example shows the connection between a SIP INVITE 
> request
> and the Diameter LIR message, any other SIP request (such as SUBSCRIBE, 
> OPTIONS, etc.) would trigger the same Diameter message.'
> 
> Could a REGISTER request trigger an LIR, and if so, in what situation?
> How does SIP server 1 determine if a REGISTER triggers an LIR or a UAR?  
> My suspicion is that the text should read '... any other SIP request 
> with the exception of a REGISTER request (such as SUBSCRIBE, OPTIONS, 
> etc.) would trigger the same Diameter message', and that a REGISTER 
> would always trigger a UAR to be sent.  But I am prepared to be told I 
> am wrong.
> 
> I also have a whole host of minor editorial comments that I will 
> forward
> on to Miguel-Angel and Maria-Carmen Belinchon away from the e-mail list.
> 
> Dan Warren
> 

-- 
Miguel-Angel Garcia                     Oy LM Ericsson AB
                                         Jorvas, Finland
mailto:[email-masked]     Phone:  +358 9 299 3553
mailto:[email-masked]        Mobile: +358 40 5140002

---

From: "Miguel A. Garcia" <[email-masked]>
Date: Thu, 10 Jul 2003 13:15:57 +0300

Dan:

I did some research and I got some convincing answers.

UAR is a request for authorization to perform an action. In the case of 
3GPP such action is always to accept a registration. The authorization 
considers whether the Public user identity is defined in the realm, whether 
hte user is allowed to roam in a particular visited network and such things.

LIR is a request for routing information. A SIP server has received a 
request address to a user of the realm, but it does not have enough routing 
information to forward it. Therefore, it contacts the Diameter server to 
ask for routing information (e.g., the address of the SIP server serving 
the user).

Therefore, both commands have different semantics, and should remain as 
different commands.

Regards,

          Miguel

Daniel Warren wrote:
> I think I might (although I also think someone in your office probably 
> could tell you too!!).
> 
> used for REGISTER because the SIP Server is the one on the call 
> originating side, so when a user registers, it is the UAR that is sent 
> to the Diameter Server to obtain the S-CSCF details and/or capabilities 
> for the subscriber and ultimately to faciliate the registration of that 
> subscriber with the network.  LIR is used on a session terminating SIP 
> Server to contact the Diameter Server for the location of the subscriber 
> but does not involve the subscriber explicitly registering with the 
> network as a consequence.
> 
> with two commands rather than one, and I am not entirely convinced that 
> this explanation justifies it.
> 
> Subject: Re: [AAA-WG]: Re: Comments: 
> draft-belinchon-aaa-diameter-mm-app-0 1.txt
> 
> 
> Hi Dan:
>