Re: reliable messaging - hop by hop

[Dan Weinreb <dlw@exceloncorp.com>]

   Date: Wed, 29 Aug 2001 15:34:37 -0400
   From: Martin W Sachs <mwsachs@us.ibm.com>

   MWS:  This is one of the really sticky points about time-to-live. One
   possibility is that once the application is made aware of the presence
   of a given message in the persistent store, that message shall not be
   deleted except by the application.  

Yes, you're right.  Once the message has reached persistent storage
at the To Party MSH, there's no longer any reason to worry about
time-to-live.	

				       If the signed NRR is returned only
   when the To application is made aware of the message, that should take
   care of this problem except that it then isn't clear what the value of
   time-to-live is.

Its value is for duplicate elimination, so that a receiver is free
to garbage-collect this message ID from its persistent table of
message ID's.  Once the message has arrived at the To MSH and
at arrival time found to not be a duplicate, we don't have to
worry about expiring it.  OK, no problem then.  "Never mind."