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RE: Layering in ebXML and WSA

From: Assaf Arkin <arkin@intalio.com>
Date: Sat, 15 Feb 2003 15:55:34 -0800
To: "Champion, Mike" <Mike.Champion@SoftwareAG-USA.com>, <www-ws-arch@w3.org>

> I don't see any responses to Roger's
> http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0073.html
> I'm especially interested in observations on his assertion that ebXML is
> heavily oriented toward early-bound, "heavy" B2B/EDI operations whereas
> typical Web services architectures are oriented toward late-bound
> and light
> operations.  This sounds plausible to me, is it more or less correct?

I think the main difference stems for the specific scope that ebXML is
taking to solve B2B problems vs the layered approach that WS is taking to
offer a more generic architecture.

Since WS takes the layering approach you need to have multiple layers in
place before you can do B2B. WSDL by itself is clearly not enough. You also
need security, transactions, RM, choreography etc. Since these can be added
to WSDL in the form of extensions, the WSDL model is certainly adequate, but
a single specification is insufficient to solve B2B problems.

At some point in time the position that WS is "not there yet" was accurate.
But there's a lot of work going on to fill the gaps. I think most of these
gaps have been addressed with propositions for new specifications and it we
look at WS as the composition of all these layers we will not find it
lacking in capabilities.

What I appreciate in the WS model is the service oriented model. For
example, I could get a "heavy" B2B engagement to work with a combination of
SOAP + WS-RM + WS-Security + WS-Tx/BTP + BPEL/WSCI + UDDI. And similarly for
a user interface I would use HTML + XSLT + CSS + single sign-on.

To get that working you need a service to manage acks, a service to create
security tokens, a service to create and demarcate transactions, a service
to negotiate SLA, a service to perform advertising and discovery. In the
'service oriented architecture' you would want to have a common base that
allows you to describe both the high level services (the B2B interactions)
and the system services that make them possible (token service, transaction
service, etc).

So in the WS world you look at all kinds of services and use combination of
layers to support lightweight, heavyweight, middleweight and any other kind
of service. WS doesn't solve a specific problem (B2B or A2A) but it allows
specific solutions to exist. And like Lego blocks it allows a heavyweight
services to emerge from the combination of middleweight and lightweight

Just my $0.02


> Finally, I'd like to see suggestions for how to discuss this in the WSA
> document. What properties, relationships, and constraints
> characterize ebXML
> messaging?
> Thanks for helping to direct this very informative discussion in
> a direction
> that is more useful to the WSA WG.
> Mike Champion
Received on Saturday, 15 February 2003 18:57:05 UTC

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