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

From: Ricky Ho <riho@cisco.com>
Date: Sat, 14 Dec 2002 16:59:49 -0800
Message-Id: <4.3.2.7.2.20021214164531.02655db8@franklin.cisco.com>
To: "Assaf Arkin" <arkin@intalio.com>, "Ugo Corda" <UCorda@SeeBeyond.com>, <www-ws-arch@w3.org>
Lets detail out ...

App-A and RM-A is running inside node-A, so here is the flow.

1) App-A --(M)--> RM-A   (App-A then wait for RM-A to report the delivery 
status)
2) RM-A --(M)--> RM-B  (using the retry mechanism we've been discussing so far)
3a) If (retry successful), then RM-A report delivery status "success" to App-A.
3b) If (retry timeout), then RM-A report delivery status "in-doubt" to 
App-A.  Now it becomes App-A's responsibility to figure out the actual status

My question is:

If nodeA crash between after point (1), why can't we simply treat that same 
as the scenario of 3(b) ?

In your proposal, do you expect ....
a) App-A to extract the message from the persistent store of RM-A, and ask 
the RM-A to resend that message ? or ...
b) RM-A automatically resend that message, but after it get an ACK, how 
does it report back to App-A (because App-A may not be running) ?

Best regards,
Ricky

At 11:58 AM 12/14/2002 -0800, Assaf Arkin wrote:
>
>-----Original Message-----
>From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On 
>Behalf Of Ricky Ho
>Sent: Saturday, December 14, 2002 7:48 AM
>To: Ugo Corda; www-ws-arch@w3.org
>Subject: 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.
>
>
>Node A wants Node B to do something. Node A creates a message and sends it 
>to Node B. Node A crashes. Node B sends an ack and starts processing the 
>message. The ack is not received by Node A since its down. Later Node A 
>comes back to life. Node A does not have any recollection of sending a 
>message to Node B, it missed the ack coming from B, so it has no clue that 
>Node B is processing the message or that it should even ask Node B "how's 
>it going with that message over there?"
>
>  arkin
>
>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 
>>
Received on Saturday, 14 December 2002 20:02:47 GMT

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