OASIS ebXML Messaging Services TC

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Re: [ebxml-msg] Generation of SequenceNumber

  • 1.  Re: [ebxml-msg] Generation of SequenceNumber

    Posted 12-14-2001 10:06
    
    Shimamura-san,
    
    You are asking for message ordering to be guaranteed across a stream of
    messages for the same conversation some of which are processed by MSH B and
    some of which are processed by MSH C.  There are these possibilities:
    
       MSH B and MSH C are really physically separate.  IMHO, you are asking to
       support a use case whose implementation would be extremely complex.
       MSH B and MSH C are separate data structures within the same physical
       MSH. That still strikes me as excessively complex.
       Your use case is valid and is a strong argument that conversation
       management, including message sequencing, belongs at an upper level of
       middleware and  not in the MSH at all.
    
    If the use case is really valid, (3) is the only sensible design.
    
    Regards,
    Martin Sachs
    
    *************************************************************************************
    
    Martin W. Sachs
    IBM T. J. Watson Research Center
    P. O. B. 704
    Yorktown Hts, NY 10598
    914-784-7287;  IBM tie line 863-7287
    Notes address:  Martin W Sachs/Watson/IBM
    Internet address:  mwsachs @ us.ibm.com
    *************************************************************************************
    
    
    
    SHIMAMURA Masayoshi <shima.masa@jp.fujitsu.com> on 12/14/2001 06:58:47 AM
    
    To:    ebxml-msg@lists.oasis-open.org
    cc:
    Subject:    [ebxml-msg] Generation of SequenceNumber
    
    
    
    Please make a small change in section "10.1.1 SequenceNumber element" as
    following:
    
        [line 2098-2101 on Page 54]
        The SequenceNumber is unique within the ConversationId and MSH. The
        From Party MSH and the To Party MSH each set an independent
        SequenceNumber as the Sending MSH within the ConversationId. It is
        set to zero on the first message from that MSH for a conversation
        and then incremented by one for each subsequent message sent.
                      |
                      V
        The SequenceNumber is unique per combination of MSH, ConversationId
        and Endpoint (target MSH's URI specified in CPA). The From Party MSH
        and the To Party MSH each set an independent SequenceNumber as the
        Sending MSH within the pair of ConversationId and Endpoint. It is
        set to zero on the first message from that MSH for a conversation to
        a Endpoint and then incremented by one for each subsequent message
        sent.
    
    Rationale:
        The current CPPA and the Message Service specification accepts
        following configuration. Because a To Party can have several
        Services, and each Service can have different Endpoint each other.
    
                                     Endpoint B
      +------+--------+   path AB    for Service B +-----------+-------------+
      |From  |Sending +--------------------------->|Receiving  +-> Service B |
      |Party |MSH A   +------+                     |MSH B      |             |
      +------+--------+      |                     +-----------|   To        |
                             |                                 |   Party     |
                             |                     +-----------|             |
                             +-------------------->|Receiving  |             |
                           path AC   Endpoint C    |MSH C      +-> Service C |
                                     for Service C +-----------+-------------+
    
        In the configuration, message order should be guaranteed per each
        path separately even if same ConversationId is used for the messages
        in both path AB and AC. Because the two Receiving MSH works
        independently each other. To clear this point, we need to add
        Endpoint to conditions of uniqueness of SequenceNumber.
    
    
    Regards,
    
    --
    SHIMAMURA Masayoshi <shima.masa@jp.fujitsu.com>
    TEL:+81-45-476-4590(ext.7128-4241)  FAX:+81-45-476-4726(ext.7128-6783)
    Planning Dep., Strategic Planning Div., Software Group, FUJITSU LIMITED
    
    
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