- 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>
Comments welcome. I've tried to incorporate ballot feedback; if you still have issues w/ intermediaries, please bring them to the group ASAP. Changes: 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.] <requirements> 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 mechanisms. 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] </requirements> -- Mark Nottingham, Research Scientist Akamai Technologies (San Mateo, CA)
Received on Friday, 10 November 2000 21:58:10 UTC