Is (sender-side) persistent storage needed for Reliable Messaging ??

Can someone elaborate why this is a need of persistent storage at the 
sender side (as said in ebXML spec) ?  I don't see such need because if the 
client system crash before getting the ACK, the message delivery status is 
"in-doubt" and the client side application has to find it out by himself 
anyway.

Rgds, Ricky

At 02:30 PM 12/12/2002 -0800, Ugo Corda wrote:

>I just reread ebXML's work on Reliable Messaging (see [1], Part II, Sec. 
>6, Reliable Messaging Module), and it looks like required reading for any 
>discussion on this subject within our group (so that we don't spend a lot 
>of time redoing what has already been done).
>
>Besides the specific syntax used, which belongs to ebXML and does not need 
>to be duplicated, I am curious to know if people find deficiencies, or 
>have any other type of observations, regarding the reliability model used.
>
>Ugo
>
>[1] 
><http://www.oasis-open.org/committees/ebxml-msg/documents/ebMS_v2_0rev_c.pdf>http://www.oasis-open.org/committees/ebxml-msg/documents/ebMS_v2_0rev_c.pdf 
>