Dale / Jacques,
Yes - this is all good.
I did look at the original postings and outcomes from Chris' Ferris
deliberations on all this back in 2000/2001 - and the issue with
encrypted payloads with digital signatures.
So the v2.x does have some support for intermediary delivery by
using the CPA - and what I'm suggesting is a very simple base case
- with limited handling derived from the partner ID and message type
checking only - and then onward routing to explicit endpoint ports
accordingly. So the intermediary can acts as an aggregator - and
then drop deliver to exact locations based on ID/type and the CPA
between the aggregator and the external partner.
Anyway - this all sounds encouraging. What I'll do is report
back and ask them to review the deliberations to this point - and then
we can look at specific use cases with them and review those
together. Seems like we should be able to provide a base
implementation model to handle 80:20 processing for them to at least
get started.
Thanks, DW
"The way to be is to do" - Confucius (551-472
B.C.)
-------- Original Message --------
Subject:
[ebxml-msg] RE: [ebxml-cppa] RE: [ebxml-msg] HL7 ORG: Fw:
Issues
with Web services transport
From: "Durand, Jacques R."
<>
Date: Tue, January 16, 2007 11:44
pm
To: "Dale Moberg" <>,
<>,
<>
Cc:
<>
>Jacques’s case can be
construed as a termination of the ebMS message and then followed by an
internal integration using SOAP. This
>functionality is add-on
functionality of a MSH (which is almost always found in real
implementations of a MSH).
Right - this is
a case of an "ultimate MSH" still acting as SOAP intermediary when there
are other SOAP nodes behind that are not supposed to understand
ebMS (e.g. WS endpoints). So still a simple case w/r to CPA (no
MSH intermediary per say) as I guess the CPA would not apply to these
ultimate SOAP nodes (correct me, Dale)
I have not
mentioned the other way to deal with the HL7 application-level
intermediation, which is to use an MSH as intermediary forwarding to
another MSH. We are gathering reqs for these scenarios which clearly
will lead to introducing a new messaging role (not in core V3) in the
messaging model - e.g. "intermediating" in addition to sending and
receiving. It appears that a CPA would be needed for such an
intermediary.
Jacques
From: Dale Moberg
[mailto:]
Sent: Tuesday, January 16,
2007 7:56 PM
To: ; Durand, Jacques R.;
Cc:
Subject: RE: [ebxml-cppa] RE:
[ebxml-msg] HL7 ORG: Fw: Issues with Web services
transport
Hi
David,
If the forwarding and routing amount
to distinct ebXML conversations, then the situation is really two ebXML
messages between two pairs of participants, call them A and B and B and
C. Then CPAs exist for each of the two
conversations.
If there are additional requirements
(such as A’s signature has to be transferred to C), then WSS
would allow a lot of new combinations in ebMS 3 that are not mentioned
in ebMS 2.0. But CPP/CPA are still between the source and destination
parties of an ebMS messaging
conversation.
So far ebMS 3.0 has not specified
exactly what to do with SOAP intermediaries. Nor is there agreement as
to whether there is a need for ebXML intermediaries with distinctive
behavior. You can always have SOAP intermediaries, but it is not clear
that there will be specific ebMS MEPs involving them. I think we have
some proposed requirements to consider in this area but we have
deferred consideration until we get some core ebMS 3.0 profiles
completed.
Jacques’s case can be construed
as a termination of the ebMS message and then followed by an internal
integration using SOAP. This functionality is add-on functionality of a
MSH (which is almost always found in real implementations of a
MSH).
Dale
From:
David RR Webber [mailto:]
Sent: Tuesday, January 16, 2007
7:23 PM
To: 'Durand,
Jacques R.';
Cc:
Subject: [ebxml-cppa] RE: [ebxml-msg] HL7 ORG: Fw:
Issues with Web services transport
Jacques,
This most helpful. I
believe your answers goes a long way to addressing this for
IHE/XDS.
One further question before
I forward this to them.
At NIH we are using
multiple CPAs in situations where forwarding and routing is occurring
– therefore – the intermediary has a CPA in place between
the originator and themselves as well as the CPA between the recipient
and NIH. Clearly this allows for additional controls and aspects
about the transport to be contained in these additional CPA(s) and then
accessed by CPAid in the envelope.
Does this potentially offer
additional configuration options for the intermediary? My sense is
probably “Yes”?
Thanks,
DW
From: Durand, Jacques R. [mailto:]
Sent: Tuesday, January 16, 2007
4:53 PM
To: David RR
Webber (XML);
Cc:
Subject: RE: [ebxml-msg] HL7 ORG: Fw: Issues with Web
services transport
The document is interesting as it
clearly raises the issue of application-level intermediation
(contrasting the "service application" with the "worker applications"),
for which the SOAP model is only a foundation - and a simplistic one w/r
to routing - yet one that should be
leveraged.
It shows the need to represent and
process differently what we could call "application
meta-data" and application data, the former being intended for
the intermediary (more horizontal SOAP headers, e.g. WSA, are probably
too low-level here).
An analogy could be the use of
"topics" in the publish-subscribe model.
> Does anything in ebMS V3.0 mitigate
this?
So I'd say that ebMS3 does (much)
better than ebMS2 on this. Both distinguish app meta-data in form of
business header elements - including payload manifest - distinct from
payload parts, helping an (unspecified) forwarding function. But
when the "worker application" is wrapped as a Web service
deployed on the back-end (as it typically would in an SOA model) the
ebMS V3 model is much friendlier to the needed conversion into a
service invocation: in V3 the ebMS header being just a SOAP header bloc
like any, and leaving the SOAP body free for business payload, can be
stripped from the SOAP message by the MSH acting as intermediary.
What remains can just be a plain Web service invocation, ready as is to
forward (you would never guess it has been an ebMS message...). We have
prototyped this at Fujitsu. One issue with ebMS2 is the SOAP body used
by the ebMS header, forcing payloads in attachments, and hard to deal
with when using end-to-end security (with V3, you could even have
security headers that the MSH would not touch,if intended to ultimate
destination - V3 Part 2 will be more explicit on this).
The paper also makes a very sound
observation regarding cases where the application needs to know
authentication credentials as context to its processing ("is this
request to this service allowed for this type of client?"). You
typically want to deal with this before the request hits the
application service or server supporting it, yet this kind of
application-level authorization (which is closer to access
control) is out of infrastructure scope in the current
Web service security model (WS-Security) - and current WSS
implementations do not seem to facilitate this. Clearly the
application-level intermediation pattern is key to supporting this. I
believe a decent support has been proposed in V3 in the "message
authorization" section which still leverages WS-Security as much as
possible.
Jacques
From: David RR Webber (XML)
[mailto:]
Sent: Thursday, January 11, 2007 7:51 AM
To: ebxml-cppa
Cc:
Subject: [ebxml-msg] HL7 ORG: Fw: Issues with Web
services transport
Importance: High
Does ebXML CPA address some of these issues? I believe
it might.
Could CPA's between participants provide the missing information
- or enough for common uses?
Does anything in ebMS V3.0 mitigate
this?
I
also think that the idea we've been working on in BCM/ebSOA/BP of a
pan-ebxml context mechanism - could also be a next peice - so a shared
context could be retained across participants - that summarizes the
salient information needed to deliver
correctly.
Please let me know so I can reply back the HL7 list with our
considerations?
I'm seeing this notion of an Uber-WS infrastructure gaining
ground - so you call that Uber-API - and then delivery occurs in the
dialect for a partner.
Of course I beleive ebXML provides a B2B superset here that plain
WSDL clearly is not able to match.
Thanks, DW
"The way to be is to do" - Confucius (551-472
B.C.)
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