Subject: AS3 Comments

From: "Kartha, Neelakantan" <[email-masked]>
Date: Wed, 21 Apr 2004 14:03:28 -0500

Here are some comments on the AS3 draft:

General Comments:

	1. AS2 (and AS3 as well) currently interpret the absence of the
"Disposition-Notification-To"
   header as implying that no MDN is needed at all. If
"Disposition-Notification-To" is present,
   AS2 ignores its value (only the presence of the header matters). Instead,
AS2 uses 
   "Receipt Delivery Option"  Header to specify the URL that the MDN must be
sent 
   to (typically HTTP url). 

   For reasons of consistency,  I propose that AS3 also use "Receipt
Delivery Option" to specify 
   the URL (typically FTP url) to send the MDN back, instead of using the
value of 
   "Disposition-Notification To" to specify the URL (as is proposed in the
draft).

   2. The spec does not mention how a synchronous MDN response can be
delivered. 
	   That a synchronous MDN is desired can be indicated, for instance,
by the absence of "Receipt Delivery Option" header (as in done by AS2).Note
that one can use the ftp control channel to send a synchronous MDN( base64
encoded) reply by taking advantage of multi-line reply format in FTP
protocol. This reply can be sent  after data transfer is completed. The
multi-line reply format would be as follows:

    226- <start of base64 encoded mdn>
    226- <content of encoded mdn one line at a time preceded with "226- "
    ...
    226- <end of base64 encoded mdn>
    226 data transfer completed.

Note that the hyphen after "226" means continuation on a separate line.
The client can process the reply excluding the last line as follows: base64 
decode the reply, then process it like regular multipart/report format. 

Comments on the Draft

       2.3.1 Under SHA-1:  Replace "recommend" by "recommended"
       3  This section does not mention RFC 822 and RFC 2376, although
Section 4.2 uses these.
       6.1 (paragraph before 6.2) Mentions two references [sftp] and
[murray] without giving pointers.
       8 (paragraph before 9) "..specified in this document". The word
"this" is ambigous: could refer to this AS3 draft or S/MIME. 
       Example A2:  Should the header be "From" or "AS3-From"?

Neelakantan Kartha