Subject: RE: [Simple] IMDN issue #8: List-Action, Original-From and Original-Message-ID

From: "Burger, Eric" <[email-masked]>
Date: Sun, 5 Feb 2006 16:38:51 -0500

It's too confusing to talk around an entirely new mechanism without
folks seeing what that mechanism is.  I thought we were going to publish
the 'new' version and then discuss it.  Rather than waiting, I just
submitted draft-burger-simple-imdn-03.  It should show up in the drafts
archive shortly.

Other stuff:
A B2BUA is a B2BUA.  When a User Agent Server gets a message, it is
supposed to act like a User Agent Server.  We give extra semantics for
things with well defined action, like a list exploder or gateway.
However, since we're changing what a UAS does with respect to SIP, we
should not recreate the errors of the messaging past and leave that as
"an exercise for the reader."  Let's take the opportunity to "do the
right thing" and let the endpoint figure out what *it* wants done.  It
is the owner of the request, after all.

Gateways: If I know that Fred at AOL/MSN/Private-Enterprise-IM-system
will never generate an IMDN, I do care that my message at least made it
into the aether.  Can't argue against this one if one argues for
IMDN-as-transport-ACK mechanism.

-----Original Message-----
From: Hisham Khartabil [mailto:[email-masked]] 
Sent: Thursday, February 02, 2006 1:44 PM
To: Burger, Eric
Cc: Simple WG
Subject: Re: [Simple] IMDN issue #8: List-Action,Original-From and
Original-Message-ID

On Feb 2, 2006, at 6:05 PM, Burger, Eric wrote:

> Yes, Original-* and List-Action could support the direct reporting
from
> the UAS to the UAC.  However, they are necessary to solve a thorny
> problem that B2BUA's introduce.  Namely, by the strict definition of
> delivery, the B2BUA MUST issue the IMDN, and that is the end of the
> story.  The B2BUA has no right to request a downstream IMDN, nor does 
> it
> have the right to relay the downstream IMDN back to the Requesting
UAC.

I disagree. That might be your definition of a B2BUA, not mine. How 
could a B2BUA issue an IMDN to a IM it has no idea if it has been 
delivered to a user or not. Especially if the IMDN is a read report.

>
> I agree the most common user interpretation of IMDN is that it is for
> the final UAS, even through a gateway or exploder, to do the
reporting.
> HOWEVER, it is no the only case.  Given that the plan below breaks the
> definition of a UAS (the UAS half of a UAC) and it does not allow
users
> or intelligent agents who really only care if the message was
processed
> at the gateway or list exploder, I would offer that we use a mechanism
> that works for all scenarios.

Can you give real world examples of such scenarios where the sender 
only cares that the GW or B2BUA has the message delivered to it.

>
> I would also offer the mechanism proposed in the text works for all
> scenarios.

Can you describe that mechanism to folks who don't have the privilage 
of seeing the pending WG item version?

>
> [Note to Hisham - are you referring to the mechanism in
> draft-burger-simple-imdn-01 or draft-ietf-simple imdn-00?  I don't 
> think
> anyone has seen draft-ietf-simple-imdn-00 yet.  The ietf-simple-imdn
> mechanism is very different (although backwards compatible) with the
> burger-simple-imdn mechanism.]

I'm referring to burger-simple-imdn-01. We cannot just change 
mechanisms without discussion on the mailing list, especially when the 
draft is a WG item.

Thanks,
Hisham

>
> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On 
> Behalf
> Of Hisham Khartabil
> Sent: Friday, January 27, 2006 10:19 AM
> To: Simple WG
> Subject: [Simple] IMDN issue #8: List-Action,Original-From and
> Original-Message-ID
>
> I don't think the List-Action header is needed. The Original-From
> header and Original-Message-ID may not be needed also. this depends on
> how we define the behaviour of the IM exploder to be.
>
> To summarise:
>
> - List-Action header is used to indicate if a B2BUA  or UAS is to do
> the reporting
> - Original-From allows a UAS to know there to send the notification if
> there was a B2BUA like an exploder on the path.
> - Original-Message-ID allows a UAS to indicate to the UAC the
> message-ID of the original message that the notification is for. This
> is also when a B2BUA is involved.
>
> All 3 headers are above to help the case that a UAC chooses for the
UAS
> to send the notifications directly instead of the B2BUA generating
them
> indicating the B2BUA's receipt of the message.
>
> I would design it as follows:
>
> - UAC indicates, in the IM, its wish to receive an IMDN
> - B2BUA forwards the IM with the necessary original-from and
> original-message-id headers (if needed)
> - the UAS generates the IMDN and sends it just like it would send an
IM
> to the UAC. For MSRP, it would be just like a SEND request in the
other
> direction. For SIP MESSAGE, it would use the from (or original-from)
> and to headers in the incoming IM to create the MESSAGE request in the
> reverse direction. Same applies for message-id.
> - If it was not possible for the B2BUA to reach the UAS, it would
> generate its own IMDNs for that IM.
>
> Regards,
> Hisham
>
>
> _______________________________________________
> Simple mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/simple
>

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---

From: Hisham Khartabil <[email-masked]>
Date: Mon, 6 Feb 2006 10:39:17 +0100

> is the owner of the request, after all.

I still would like to see use cases here. I can't think of any.

> IMDN-as-transport-ACK mechanism.

How would u know? also, this is the gateways as well as 
AOL/MSN/Private-Enterprise-IM-system problem, not the user. Those 
protocols need to define their IMDN, otherwise IMDN cannot be reported 
back through the GW. Simple as that. What good is the information that 
the GW got it but not the end user???

Hisham