Subject: [Sip] Open Issue #188: Reply-To

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 6 Dec 2001 02:08:21 -0500

Issue:

Do we want to add a Reply-To header? Presumably, this is the URL to use to 
return calls at a later time. Its different from Contact, in that its a
logical 
address. Its not From/To, since they could be different. Example:

INVITE sip:[email-masked]
From: sip:[email-masked]
To: sip:[email-masked]
Contact: sip:[email-masked]
Reply-To: sip:[email-masked]

Discussion:

From a technical perspective, another alternative would be to define an
additional rpi-id-type in the Remote-Party-ID header, which indicates the
reply address type. R-P-ID has become the repository of identities not
already provided by other headers (althouth R-PID is more meant for network
authenticated identities, and thats not this), so it could fit there. Its a
bit ugly, since it would diverge from many other rfc822 based applications
which have defined and used this header.

This header becomes a bit more important with MESSAGE defined. 

Another alternative is to stick it into an extension by itself. That seems
silly, since this is such a small, simple extension that it would be a
waste.

Putting it in bis is easy enough, and its backwards compatible. But, do we
want to be adding things at this time, rather than taking away?

Proposal:

Its simple. Its compatible. Its well understood. Its going to really be
needed for MESSAGE, probably other things. Let us take the simple route and
add it.

-Jonathan R.

---
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

_______________________________________________
Sip mailing list  http://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip

---

From: Dean Willis <[email-masked]>
Date: Thu, 06 Dec 2001 11:52:51 -0600

Personally, I kind of like Reply-To, so I'd suggest just putting it into 
bis.

--
Dean

---

From: Alan Johnston <[email-masked]>
Date: Thu, 06 Dec 2001 12:02:51 -0600

I like this as well.  This is a problem that currently exists in some UAs -
their call return button does not work because the wrong URI (or part of a URI)
is cached for the return call.

Alan Johnston
WorldCom
sip:[email-masked]

---

From: "Vijay K. Gurbani" <[email-masked]>
Date: Fri, 07 Dec 2001 01:10:51 -0600

> Reply-To: sip:[email-masked]
[...]
> needed for MESSAGE, probably other things. Let us take the simple route and

While I have no problem in adding this, we need to ensure that the spec
is
clear on what to do if both Contact and Reply-To are present along with
R-R headers.  In creating a Route set, the Reply-To will take
precedence,
I presume.

- vijay
--
Vijay K. Gurbani  vkg@{lucent.com,research.bell-labs.com,acm.org}
Internet Software/IN Architecture Group 
Lucent Technologies/Bell Labs Innovations 263 Shuman Blvd., Rm 1A-413
Naperville, Illinois 60566     Voice: +1 630 224 0216   Fax: +1 630 713
0184

---

From: "Brett Tate" <[email-masked]>
Date: Fri, 7 Dec 2001 04:20:39 -0500

> needed for MESSAGE, probably other things. Let us take the 

It seems like an ideal candidate for a 
new extension draft or a new version of 
sip-privacy.

What is its relationship to From and 
Remote-Party-ID?  

How many entries can it contain?  If more 
than 1, should something like a q-value 
be present to communicate the meaning of 
more than 1 value being present?

Should it contain an expiration value?

Should it have a similar definition to 
Remote-Party-ID so that privacy and trust
issues can be communicated?

---

From: "Bob Penfield" <[email-masked]>
Date: Fri, 7 Dec 2001 08:44:06 -0500

Vijay,

I think you misunderstood the use of Reply-To. It would not be used instead
of the Contact. It would not really be used in the current session. It would
be used as the "To" (and probably Request-URI) when the called party "called
back" to the calling party of this session with a new session and a new
INVITE.

cheers,
(-:bob

Robert F. Penfield
Chief Software Architect
Acme Packet, Inc.
130 New Boston Street
Woburn, MA 01801
[email-masked]