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Proposed changes to 8xx

From: Mark Nottingham <mnot@akamai.com>
Date: Fri, 10 Nov 2000 18:57:34 -0800
To: XML Distributed Applications List <xml-dist-app@w3.org>
Cc: Henrik Frystyk Nielsen <frystyk@microsoft.com>
Message-ID: <20001110185733.A7647@akamai.com>

Comments welcome. I've tried to incorporate ballot feedback; if you still
have issues w/ intermediaries, please bring them to the group ASAP.

  R 800 - dropped (redundant)
  DR 811 - new (explict requirement for processing intermediaries)
  DR 805 R807 DR809 DR810 - moved to use cases (to be presented)
  R802 R803 R806 R808 - light massaging (no semantic changes)

[EDs: Please respect bullet list formatting.]


3.4 Intermediaries

Intermediaries are essential parts of building distributed systems that
scale on the Web. Because XML Protocol separates the message envelope from
the transport binding, two types of intermediaries are possible; transport
intermediaries and processing intermediaries.

3.4.1 Transport Intermediaries

Transport intermediaries are interposed by a transport binding, as part of
the message exchange pattern that it implies. They do not define a
processing model for messages; they only operate as part of the transport
binding. Transport intermediaries are typically used as message routing

XML Protocol must not preclude the use of transport bindings that define
transport intermediary roles such as store-and-forward, proxies and
gateways. [R803]

3.4.2 Processing Intermediaries

Processing intermediaries are XML Protocol processors; they process the
message, but are not the ultimate recipient of it. They may be colocated
with transport intermediaries, using them as a routing mechanism, or they
may use in-message routing mechanisms. Processing intermediaries are
typically used to transform, partially process or add functionality to
messages en route.

XML Protocol must define and accommodate processing intermediaries. [DR811]

To enable the interposition of processing intermediaries into the message
path, two core requirements must be met;

* Targeting - XML Protocol must define mechanisms to enable identification
  of message components to be processed by a particular processing
  intermediary. Message components must be able to be targeted at one or
  more processing intermediaries.  [R806]

* Reporting - XML Protocol must enable the generation of status and/or error
  messages by processing intermediaries, and enable propagation and proper
  identification of status and/or error messages through processing
  intermediaries.  [R808]

XML Protocol must also enable processing intermediaries to locate and
process the portions of messages intended for them without reading or
processing the entire message. [R802]


Mark Nottingham, Research Scientist
Akamai Technologies (San Mateo, CA)
Received on Friday, 10 November 2000 21:58:10 UTC

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