Subject: [Sip] Re: One remaining GRUU issue: GRUUs for non-GRUU UA

From: "Peter Musgrave" <[email-masked]>
Date: Wed, 28 Mar 2007 11:42:19 -0600

Hi, 

I agree this is a feature. 

I have a clarification question w.r.t 6.1

In the case where a proxy targets a gruu reference to a UA which does
not support gruu should the proxy keep the rule in 6.1

   processing proceeds as it would for any

   other URI present in the location service, as defined in Section 16.5

   of RFC 3261, except that the "gr" parameter is not removed as part of

   the canonicalization process.  

So a UA which does not support gruu will get a "gr" parameter. 

1)    Do we risk confusing UAs which are not supporting gruu?

2)    If it's a temp-gruu reference will the UA understand it at all?
(since it is only RECOMMENDED in 3261

that a UAS accept a To: header it does not understand)

Should a proxy which is sending to a UA which does not support gruu,
strip the gr params (and replace a temp-gruu with the AOR from the UAs
REGISTER) ?

Thanks,

Peter Musgrave

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From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 28 Mar 2007 15:07:52 -0400

inline.

Peter Musgrave wrote:

> So a UA which does not support gruu will get a “gr” parameter.

No, sorry this is confusing.

Its not removed as part of the canonicalization process; that process is 
  used to look up the gruu to obtain the matching registration. However 
once you find a match you rewrite the r-uri with the resulting contact 
and of course the gr parameter is not there in the registered contact. 
So a UA that doesn't support GRUU will never see a GRUU in the r-uri, 
it'll always be its registered contact.

SOmeone else had the same comment privately so I suspect I need to 
clarify this text.

-Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
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Cisco Systems
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From: "Peter Musgrave" <[email-masked]>
Date: Wed, 28 Mar 2007 13:16:15 -0600

Ok. So that fixes the r-uri

If the To: header has a gr in it's URI what happens to that as it is
proxied? I am concerned that if it's a temp-gruu the non-gruu UA
recipient may decide to reject it.

Peter Musgrave

-----Original Message-----
From: Jonathan Rosenberg [mailto:[email-masked]] 
Sent: Wednesday, March 28, 2007 3:08 PM
To: Peter Musgrave
Cc: [email-masked]
Subject: Re: One remaining GRUU issue: GRUUs for non-GRUU UA

inline.

-Jonathan R.

---

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 28 Mar 2007 16:40:17 -0400

The To header field would still be the GRUU. However this is no 
different than a UA which receives a request because a call was 
forwarded, the TO header won't match its own identity.

-Jonathan R.

Peter Musgrave wrote:

>>   other URI present in the location service, as defined in Section
> 
> 16.5
> 
>>   of RFC 3261, except that the "gr" parameter is not removed as part
> 
> of
>

---

From: [email-masked]
Date: Wed, 28 Mar 2007 17:06:37 -0500

From: "Peter Musgrave" <[email-masked]>

But it will often happen that the To URI has no visible correspondence
to the request-URI.  A UA should never reject a request based on the
To URI, unless it is syntactically invalid.

Dale