Subject: [Sipping] Reason in responses

From: Gonzalo Camarillo <[email-masked]>
Date: Sat, 29 Oct 2005 21:32:06 +0300

Folks,

in the thread about service retargetting, it has been said a number of 
times that a 302 response may contain a 486 status code in a Reason 
header field. Even H-I says this is possible.

Let me clarify this. When we wrote the Reason spec (RFC 3326), the 
intention was to only allow it to appear in requests. However, at that 
time, Jonathan was working on a solution to HERFP that consisted of 
encapsulating final response codes in a provisional response. That's why 
we chose to allow Reason header fields only in responses whose 
definition *explicitly* said so. That is, we expected the definition of 
the new provisional response resolving the HERFP problem to state that 
it would contain a Reason entry with the final status code in it.

You can read the text we came up with in Section 2 of RFC 3326:

   "The Reason header field MAY appear in any request within a dialog, in
    any CANCEL request and in any response whose status code explicitly
    allows the presence of this header field."

This means that Reason cannot appear in, among others, 302 responses. 
Actually, it cannot appear in any existing response.

Therefore, if we want to allow Reason entries in any response, we need 
to study the implications of doing so, and generate a document 
specifying it.

Hope this clarifies things.

Cheers,

Gonzalo

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---

From: "Jesske, R" <[email-masked]>
Date: Mon, 31 Oct 2005 07:42:31 +0100

Gonzalo,
here is a first try but no comments so long.

You can find my draft under:
http://www.ietf.org/internet-drafts/draft-jesske-sipping-etsi-ngn-reason-00.txt

Roland
> -----Ursprüngliche Nachricht-----
> Von: [email-masked] 
> [mailto:[email-masked]] Im Auftrag von Gonzalo Camarillo
> Gesendet: Samstag, 29. Oktober 2005 20:32
> An: sipping
> Cc: Paul Kyzivat; Dean Willis; Elwell, John; Mary Barnes; 
> Francois Audet
> Betreff: [Sipping] Reason in responses
> 
> 
> Folks,
>

---

From: "Elwell, John" <[email-masked]>
Date: Mon, 31 Oct 2005 08:03:23 +0000

Gonzallo,

That was exactly my understanding, and therefore my earlier
redirection-reason draft specified the possible inclusion of the Reason
header in a 3xx response. However, the more recent service-retargeting
draft, if we choose to go down that route instead, obviates the need for the
use of the Reason header in this way.

John

> -----Original Message-----
> From: Gonzalo Camarillo [mailto:[email-masked]] 
> Sent: 29 October 2005 19:32
> To: sipping
> Cc: Mary Barnes; Paul Kyzivat; Elwell, John; Francois Audet; 
> Dean Willis
> Subject: Reason in responses
> 
> Folks,
>