Re: Application Headers

[Christopher Ferris <chris.ferris@east.sun.com>]

David,

Please see below.

Cheers,

Chris

"Burdett, David" wrote:
> 
> Chris
> 
> Actually, I think there are two cases here:
> 1. Additional data that needs to be understood by the MSH, and
> 2. Additional data that needs to be understood by the application.
> 
> I guess the former is covered by the wildcard element within the header
> element, and the latter is the responsibility of the application.
> 
> Does this mean that we need to:
> 1. Include a mustUnderstand on the wildcard element?

Yes, I think that Robert's recent comments cover that. Certainly,
we have discussed it and it should be the case...

> 2. Remove the mustUnderstand on the ApplicationHeaders

Maybe it is a different attribute name...

> 
> There are also issues around saying a MSH mustUnderstand the extensions in
> that which MSH mustUnderstand it when a message is going through several
> hops.

Good point...

> 
> So perhaps we should an optional mustUnderstand to the header element with a
> semantic that the To Party MSH is the MSH that must understand it, and to
> the Routing Header which is that the receiving MSH (which may be an
> intermediate MSH) must understand it.
> 
> For applicationHeaders, I think we should perhaps remove the mustUnderstand
> and just require the MSH to make the data available to an application that
> wants it. If the receiving application does not ask for it or cannot
> understand it, then it is an application not a message service problem.

That might be an option...

> 
> Thoughts?
> 
> David
> -----Original Message-----
> From: Christopher Ferris [mailto:chris.ferris@east.sun.com]
> Sent: Friday, January 05, 2001 7:20 AM
> To: Burdett, David
> Cc: ebXML Transport (E-mail)
> Subject: Re: Application Headers
> 
> David,
> 
> Well, there are two aspects to this...
> 1) the receiving "application" MUST be capable of processing the
> namespace qualified application headers that are qualified with
> a mustUnderstand=true
> 2) the receiving MSH MUST be capable of forwarding/providing
> the namespace qualified application headers that are qualified with
> a mustUnderstand=true to the receiving application
> 
> In either case there needs to be an exception/error reported.
> 
> However, since these are "application" headers, the "application"
> needs to be notified... Hmmm... we may have a layering issue
> to deal with here...
> 
> Chris
> 
> "Burdett, David" wrote:
> >
> > Lines 841-845 say ...
> >
> > >>>An ApplicationHeaders element that has a mustUnderstand set to a value
> of
> > true means that a receiving MSH MUST be capable of understanding the
> meaning
> > of the namespace-qualified element content. If the content is not
> > understood, the receiving MSH MUST respond with a message that includes an
> > errorCode of NotSupported in an Error element as defined in section
> 8.8.<<<
> >
> > I don't think that the MSH must understand the elements. It only needs to
> > recognize the namespace qualified elements and know that it has an
> > application that can handle them.
> >
> > Thoughts?
> >
> > David
> >
> > Solution Strategy, Commerce One
> > 4400 Rosewood Drive, Pleasanton, CA 94588, USA
> > Tel: +1 (925) 520 4422 (also voicemail); Pager: +1 (888) 936 9599
> > mailto:david.burdett@commerceone.com; Web: http://www.commerceone.com
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