Subject: draft-ietf-fax-timely-delivery-02.txt

From: Hiroshi Tamura <[email-masked]>
Date: Wed, 14 Feb 2001 18:05:05 +0900 (JST)

Graham,

There are lots of changes from the previous version. But,
I think it becomes well-refined, although I do not yet understand
the latest version well.

At first, I have two questions, which may be very basic.

1. TIMELY option

Why is 'interval' value of TIMELY option in MAIL FROM unchanged
in all SMTP sessions? How do the relay MTA and the final MTA
use this value?

2. The conditions that the final MTA returns 'success'(delivered) DSN

The second paragraph in Section 3.3 says,
-----------------------------------
  Before generating a success DSN message, the final MTA must ensure
  that all of the conditions for delivery of the message have been
  achieved.  Specifically, when the TIMELY option is used, it should
  ensure that final delivery to the MUA will be completed within the
  delivery interval indicated.
-----------------------------------

I want to know the meaning of "delivery interval indicated".
I would like to use the specific example in Section 7.1.

-----------------------------------
     S: 220 Harper.org ESMTP server
     C: EHLO Benden.net
     S: 250-Harper.org
     S: 250-DELIVERBY 10,TIMELY
     S: 250 DSN
     C: MAIL FROM:<[email-masked]> BY=16;R TIMELY=20 \
        ENVID=EE271828 RET=HDRS
AAA  S: 250 OK
     C: RCPT TO:<[email-masked]> NOTIFY=SUCCESS,FALURE \
        ORCPT=rfc822;[email-masked]
     S: 250 OK
     C: DATA
     S: 354 Send data
     C: (message data goes here)
         :
        .
BBB  S: 250 Message received

  At this point, the delivery MTA Harper.org has accepted
  responsibility to achieve message disposition or to report a
  failure.  This will depend on some kind of cooperation with the
  receiving user agent.  When disposition is completed within the
  specified interval, a DSN report is sent in the following fashion:
-----------------------------------

My question is,
If the MUA retrieves his mail within '16' seconds after it stores
in his mail box of the final MTA, can the final MTA issue issue
a "delivered" DSN? Or the specified interval is '16' minus
the interval between 'AAA' and 'BBB'(I put 'AAA' and 'BBB'
the above SMTP sequence)?

Regards,
--
Hiroshi Tamura, Ricoh Company, LTD.
E-mail: [email-masked]

---

From: Graham Klyne <[email-masked]>
Date: Wed, 14 Feb 2001 11:34:21 +0000

Tamura-san,

Thank you for your comments.  I think you raise some details that need to 
be made more clear.

>in all SMTP sessions? How do the relay MTA and the final MTA

Oh yes, the reason for that got rather buried.  I propose adding a 
paragraph in section 3.2:

The TIMELY parameter, in the MAIL FROM command of a message in transit, is 
copied unchanged when the message is retransmitted.  Thus, any originally 
specified time interval is conveyed to the final MTA, to be used as a basis 
for selecting a delivery interval for returning a timely notification.
<<<

>The second paragraph in Section 3.3 says,

Hmmm... I think that should read "final delivery to and disposition by..."

>I want to know the meaning of "delivery interval indicated".

It means the remaining interval for delivery, as specified by the received 
BY= parameter.  I'll try and clarify the text.  Suggested revision reads:

Before generating a success DSN message, the final MTA must ensure that all 
of the conditions for delivery of the message have been 
achieved.  Specifically, when the TIMELY option is used, it should ensure 
that final delivery to and processing by the MUA will be completed within 
the delivery interval indicated as the value of the BY parameter of the 
received MAIL FROM command.
<<<

I rephrase thus:

At this point, the delivery MTA Harper.org has accepted responsibility to 
achieve message disposition or to report a failure within 16 seconds of 
receiving the MAIL FROM command.  This will depend on some kind of 
cooperation with the receiving user agent.  When disposition is completed 
within the specified interval, a DSN report is sent in the following fashion:
<<<

I also think the following should be added to section 3.2 and 3.3:

The time interval for completion of final delivery and processing should be 
taken to start with receipt of the MAIL FROM command.
<<<

Does this help clarify the issue?

Also, section 6.3 has some discussion of timing issues.

#g

---

From: Dan Wing <[email-masked]>
Date: Wed, 14 Feb 2001 09:23:37 -0800 (PST)

> received MAIL FROM command.

How would the final MTA (actually, MSA -- Mail Storage Agent) know when
the MUA has "processed" the message?  If the MSA has a POP3 or IMAP4
server, the simple act of retreiving and deleting the message doesn't
indicate successful "processing" of the message.

-d

---

From: Graham Klyne <[email-masked]>
Date: Wed, 14 Feb 2001 21:34:51 +0000

>indicate successful "processing" of the message.

The exact mechanism is explicitly out-of-scope.

But the memo does say that it is presumed there is some cooperation between 
the delivery MTA and the receiving MUA.  In the same way, I suppose, that 
it is presumed that delivery MTA hands of to the MUA, without SMTP actually 
specifying how this is done.

In this case, there may be no MSA as such;  e.g. for fax, the "UA" may be a 
printer, and the delivery MTA may queue a received message to the printer.

As to what constitutes processing/disposition, that too is not absolutely 
laid down.  It is suggested that for a receiving message store, retrieval 
from the store may be considered to be followed by immediate 
processing.  The whole thrust of this aspect of the proposal is that there 
exists a relationship between the delivery MTA and receiving MUA that 
allows such assertions to make sense.  In the absence of such relationship, 
the message should not be accepted for timely processing.

Make sense?

#g

------------
Graham Klyne
([email-masked])

---

From: Dan Wing <[email-masked]>
Date: Wed, 14 Feb 2001 13:44:44 -0800 (PST)

> the message should not be accepted for timely processing.

I didn't realize you were overloading the term 'delivery'.  Delivery
has always ment the final MTA (the MSA) has successfully deposited the
mail in the user's "mbox" file (or similar for the platform).

Delivery doesn't include the MUA pulling the message, the MUA processing
the message, or the MUA deleting the message.

Perhaps a similar term could be used, but something other than 'delivery',
as it's being used with a different meaning than 'deilvery' in the
traditional sense used with SMTP such as with Deilvery Status
Notifiactions (DSNs) which don't involve the MUA at all, but rather
just the final MTA (the MSA).

-d

---

From: Hiroshi Tamura <[email-masked]>
Date: Thu, 15 Feb 2001 10:11:56 +0900 (JST)

Graham,

> for selecting a delivery interval for returning a timely notification.

OK. I see what you intend.

> received MAIL FROM command.

Yes, that's what I asked for.

> within the specified interval, a DSN report is sent in the following fashion:

OK.

> taken to start with receipt of the MAIL FROM command.

Good addition.

> Does this help clarify the issue?

Yes, of course.

When i have much time, I read again.

Regards,