Re: [Sip] RFC 3261 supported header in 1xx responses

If a proxy genreates the 1xx itself, it is effectively acting as a UAS, 
in which case insertion of Supported is fine. This won't confuse a UAC 
since any 1xx generated by the proxy itself will have different tags 
from a 2xx or other responses generated by the actual UA, and thus 
represent a different (early) dialog.

A proxy cannot insert or modify a Supported header in a response that 
passes by it (i.e., one for which it is proxying).

-Jonathan R.

Arunachalam Venkatraman (arunvenk) wrote:

> Can a proxy add Supported? Is this disallowed?
> If proxy may do so, the Supported cannot be interpreted as UAS
> capabilities, even if the 1xx is reliable (consider INVITE with
> Require:100rel).
> 
> -----Original Message-----
> From: sip-bounces@ietf.org [mailto:sip-bounces@ietf.org] On Behalf Of
> Jonathan Rosenberg (jdrosen)
> Sent: Friday, November 18, 2005 5:39 PM
> To: Brett Tate
> Cc: sip-ietf
> Subject: Re: [Sip] RFC 3261 supported header in 1xx responses
> 
> It makes sense to include them in a dialog forming response. A normal
> 1xx is not dialog forming. My suspicion (though I didn't check if this
> was true) is that it went away when 100rel moved out of 3261. It can't
> hurt to send them, of course, but it would be ignored unless its
> reliable.
> 
> -Jonathan R.
> 
> Brett Tate wrote:
> 
> 
>>Within early versions of draft-ietf-sip-rfc2543bis, the Supported 
>>header could be expected within 1xx responses.  However within
>>draft-ietf-sip-rfc2543bis-06 it was removed and remains so within RFC
> 
> 3261.
> 
>>Is there a reason why it is undesirable to indicate supported 
>>extensions within a 1xx?  Or was it just an oversight when changing 
>>the "Summary of header fields" table to indicate 2xx instead of all
> 
> responses?
> 
>>
>>
>>
>>_______________________________________________
>>Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
>>This list is for NEW development of the core SIP Protocol Use 
>>sip-implementors@cs.columbia.edu for questions on current sip Use 
>>sipping@ietf.org for new developments on the application of sip
>>
> 
> 

-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Director, Service Provider VoIP Architecture   Parsippany, NJ 07054-2711
Cisco Systems
jdrosen@cisco.com                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
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_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sipping@ietf.org for new developments on the application of sip