[ebxml-msg] How do you know where a message came from?

[Dan Weinreb <dlw@exceloncorp.com>]

Hi.  On the last day of the F2F meeting, we had a discussion about how
MSH's are named, i.e. if the From Application wants to tell the From
MSH to deliver a particular message to destination D, what is the
datatype of D?  I had thought that the answer was a PartyId, but you
and others explained to me that a PartyId value would typically
correspond to an entire corporation, which might have a large number
of distinct destination MSH's.  The datatype of D is really "URL".  If
an application wants to use the MS protocol, and wants to use a CPA,
it would look in the CPA's CPA/PartyInfo/Transport/@transportId
attribute in order to find the URL that names D.

I've been thinking about that, and I have a question: if my MSH
receives an ebXML message, how do I determine which MSH it came
from?  Previously, I had thought that MSH's were named by PartyId's,
and the source of the arriving message would be found in the
MessageHeader/From/PartyID field.  But now I don't know how to
determine the originating MSH.

Thanks!

-- Dan Weinreb