Re: T2 Retry with Delivery Receipt

[Dan Weinreb <dlw@exceloncorp.com>]

   Date: Fri, 14 Sep 2001 09:24:42 -0400
   From: Martin W Sachs <mwsachs@us.ibm.com>

   Sure but it is an example of how ebxml end to end RM can work through
   unreliable IMs.

It's an extremely important point that an SMTP mailer is not an IM.

The basic scenario involving an SMTP mailer is where the From host
sends email to host M, running a store-and-foward mailer, and then
host M later sends email to the To host.  This is *not* a multi-hop
ebXML MS connection.  It is a single-hop connection.  It is *not* like
Figure 8-2.  The From MSH calls the communcation layer saying "send
this message to the To MSH".  If the From MSH is using RM and does not
get an Acknowledgement, it retries, using plain vanilla hop-to-hop
retry.  The fact that there is an SMTP mailer in there is entirely
invisible to the MSH layer.  There is no need in this particular
example to add end-to-end retry and a RetryCount field in addition to
hop-by-hop retry, because it's just one hop.

-- Dan