Subject: Call Transfer and Requested-By

From: Michael Pham <[email-masked]>
Date: Tue, 29 Feb 2000 10:29:18 -0500

Could someone comment on how the Requested-By header should be populated
in a blind transfer scenario where Requested-By is included in the
Invite request sent to the transferred-to party? It's my understanding
that Requested-By should identify the party initiating the transfer so
using the From/To header (from the Bye) does not always guarantee the
true endpoint requesting the transfer. Would using the Contact header be
more appropriate?

Regards,
Michael

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From: Jonathan Rosenberg <[email-masked]>
Date: Fri, 03 Mar 2000 00:57:05 -0500

Good question. The original thinking is that it would be populated with
the From field of the BYE. However, if the original call was forwarded,
the From field isn't going to be the actual person doing the transfer.
Unfortunately, the multiparty conferencing stuff relies on the From
field being what is used in Requested-By.

Ignoring that problem for the moment, considering just transfer, Contact
isn't the right thing either. The address in Contact is usually a fully
qualified hostname, when you want something thats more of a logical
identifier. An alternative would be to actually have a Requested-By
header in the BYE itself, and the URL in there is copied into the INVITE
triggere from the transfer.

-Jonathan R.

-- 
Jonathan D. Rosenberg                       200 Executive Drive
Chief Scientist                             Suite 120 
dynamicsoft                                 West Orange, NJ 07052
[email-masked]                     FAX:   (732) 741-4778
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http://www.dynamicsoft.com

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From: "Alex Doyle" <[email-masked]>
Date: Fri, 3 Mar 2000 11:10:52 -0500

Jonathan, Michael --

I'm not sure I agree -- isn't there a distinction here between:
- call redirection (forwarding to a User's new location)
- user forwarding (forwarding to a new User)

If you're talking about "forwarding" with the 3xx Redirection, then that
isn't really true User forwarding, it's more like User mobility.  If A calls
B, and B's server redirects, then the call is being redirected to a new
location on behalf of B.  B is still the terminating party, and still the
party that would send a BYE(Also), right?

If you're talking about User forwarding (A calls B, B forwards to C), well,
that's a separate problem.  I'd argue that you wouldn't use a 3xx
Redirection for that call...because your To: field won't be correct.  (Maybe
that service is done better by making the server act like a back-to-back
UA.)

I still don't see the basic need for an endpoint adding the Requested-By to
the BYE(Also) -- it seems like the From field in the BYE should always be
sufficient to identify the endpoint requesting the transfer.  If it *isn't*
sufficient, then I'd argue that perhaps the initial INVITE wasn't correct.

Comments?

Alex

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]]On Behalf Of Jonathan
Rosenberg
Sent: Friday, March 03, 2000 12:57 AM
To: Michael Pham
Cc: [email-masked]; [email-masked];
[email-masked]
Subject: Re: Call Transfer and Requested-By

-Jonathan R.