- From: <john_ibbotson@uk.ibm.com>
- Date: Wed, 14 Mar 2001 09:02:01 +0000
- To: "Williams, Stuart" <skw@hplb.hpl.hp.com>
- cc: "Henrik Frystyk Nielsen (E-mail)" <frystyk@microsoft.com>, "Jean-Jacques Moreau (E-mail)" <moreau@crf.canon.fr>, "Krishna Sankar (E-mail)" <ksankar@cisco.com>, "Lynne Thompson (E-mail)" <Lynne.Thompson@unisys.com>, "Marc Hadley (E-mail)" <marc.hadley@uk.sun.com>, "Mark A. Jones (E-mail)" <jones@research.att.com>, "Martin Gudgin (E-mail)" <marting@develop.com>, "Nick Smilonich (E-mail)" <nick.smilonich@unisys.com>, "Oisin Hurley (E-mail)" <ohurley@iona.com>, "Scott Isaacson (E-mail)" <SISAACSON@novell.com>, "Yves Lafon (E-mail)" <ylafon@w3.org>, "'xml-dist-app@w3.org'" <xml-dist-app@w3.org>
Stuart, I like the revised diagram but have one minor revision which may address Jean-Jaque's and Henrik's issues. I believe that there are two types of handlers. Those that are visible to the upper application layer and those that are completely enclosed within the XMLP layer. The purpose of those entirely within the XMLP layer is to provide additional funcionality to the infrastructure services used by the application. These are services that the appication can rely on but does not have to interact with. An obvious candidate is reliability. An application assumes that the XMLP layer will handle reliable delivery but does not need to interact or have visibility of how the layer does it. A handler that understands retries, sequence numbers, block numbers and all the other state variables associated with reliable delivery can exist entirely within the XMLP layer - the application should not interact with it. Other examples of handlers within the XMLP layer may include those that support more complex message patterns. The second type is where an application interacts directly with the handler. The obvious candidate for this are handlers linked to payload blocks where the contents of the message have to be delivered to the application for further business processing. I think this highlights an important distinction between the "application" and "infrastructure" layers within XMLP. John XML Technology and Messaging, IBM UK Ltd, Hursley Park, Winchester, SO21 2JN Tel: (work) +44 (0)1962 815188 (home) +44 (0)1722 781271 Fax: +44 (0)1962 816898 Notes Id: John Ibbotson/UK/IBM email: john_ibbotson@uk.ibm.com
Received on Wednesday, 14 March 2001 04:34:03 UTC