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Subject: RE: [ebxml-cppa-negot] NDD Schema and Sample NDD instance documen t
Kartha,
Please see my replies below, labelled MWS:.
It is important that everyone review and comment.
Regards,
Marty
*************************************************************************************
Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown Hts, NY 10598
914-784-7287; IBM tie line 863-7287
Notes address: Martin W Sachs/Watson/IBM
Internet address: mwsachs @ us.ibm.com
*************************************************************************************
"Kartha,
Neelakantan" To: Martin W Sachs/Watson/IBM@IBMUS
<N_Kartha@stercom cc: ebxml-cppa-negot@lists.oasis-open.org
m.com> Subject: RE: [ebxml-cppa-negot] NDD Schema and Sample NDD instance documen t
09/30/2002 12:33
PM
Marty,
Thank you for your remarks and your clarification to my comments. Here are
some follow up remarks in response to your comments.
1. It seems that there are two related, although slightly different
approaches now on the table. Let me first describe them. To start with,
Party A has CPP_A and and NDD_A that points to CPP_A. Party B has CPP_B and
NDD_B that points to CPP_B.
MWS: One immediate problem is that the CPPA specification permits
publishing
CPA template instead of a CPP. I believe that this means that we would
have
to provide "Approach that Marty proposed" even if we agree to include
Kartha's
approach.
Approach I proposed:
1. Party A and Party B negotiate on elements that are in the CPP and come
to an agreement on them. NDD_A and NDD_B are used during this process.
MWS: CPP-A and CPP-B also have to be used in this process.
MWS: One possible problem here is that because there is no CPA template at
this stage, everything that is negotiable in both CPPs have to be
considered
during this part of the negotiation process. Composing a CPA template
first
mechanically resolves all negotiable items that can be resolved by simple
matching between the two CPPs and extracting the commonalities. See the
discussion in the CPA composition appendix of the CPPA spec.
2. One of the parties (say party A) now makes a CPA template that contains
the agreed upon values produced in step 1, as well as elements that are
specific to the CPA
(such as start, end etc.). Party A also produces an NDD1_A, that points to
the
CPA template. Note that NDD1_A does *not* refer to the elements of the CPP,
since they
already have been negotiated and agreed upon. NDD1_A only points to the CPA
specific
elements in the CPA template. Note however that the negotiability
requirements that
may be put in NDD1_A might depend on the first negotiation.
3. Consequently Party B also produces a similar NDD1_B template.
MWS: Rather than working with two separate NDDs at this stage, I think it
would be easier to produce a single NDD that refers to the draft CPA
template
and incorporates both parties' requirments on the CPA-only elements. The
process of
composing that combined NDD would detect any incompatibilities.
4. Party A and B negotiate on the elemtns that are in the CPA template and
come to
an agreement on them. NDD1_A and NDD1_B are used in this process.
Approach that Marty proposed:
1. Party A composes a preliminary CPA template using CPP_A, CPP_B, NDD_A
and
NDD_B.
In this CPA template, party A also inserts any CPA specific element like
start, end.
2. Party A now produces a new NDD (call it NDD_1_A_B) that expresses its
own
and
Party B's negotiability requirements.
3. A and B then negotiate and come to agreement using NDD_1_A_B
A few remarks and questions:
1. A simple implementation of my approach can assume that that Steps 1 and
Step 4 can
be negotiated independent of each other. If we take that approach, the
information in NDD1_A and NDD1_B can be made available at step 1 itself by
each of them
pointing to some standard CPA (such as the one available with the spec).
Note that
NDD1_A and NDD1_B can point only to CPA specific elements.
2. If as in Marty's approach an NDD (such as NDD_1_A_B) needs to refer to
its own and the other parties negotiability requirements, the current
schema
needs to change so as to enable it to have a pointer to negotiability
requirements of both parties.
MWS: I don't think so. The combined NDD would refer only to the CPA
template.
For instance, if party A wants to have the
cardinality of an element betwen 1 and 4 (with
preference for lower cardinalities) and party B wants to have the
cardinality of that
element between 2 and 3 (with preference for the higher cardinalities), it
seems that
both these should be represented in the initial NDD_1_A_B. Is this the way
you were
thinking about it, Marty?
MWS: Not exactly. I was assuming that Party A
would compose a single NDD that would encompass both parties' requirements
to the extent that the other party's requirements are acceptable to party
A.
So, for example, if (in the example above), Party A would
state the cardinality as 1-4 and then they would negotiate. Or, Party A
could
state an enumeration as the inclusive OR of both parties' requirements on
that
enumeration. Of course, since Party A is making the initial offer, Party A
would exclude from the NDD any constraints that are unacceptable to Party
A.
MWS: The approach that I suggested gives the party making the initial
offer
has some advantage over the other party, which could be good or bad. The
good part is that by initially filtering out the unacceptable parts of
Party B's
requirements, the negotiation may proceed more rapidly. This is in addition
to
the advantage that the CPA template composition process converges all
negotiable
items that can be resolved by simple matching.
MWS: I believe that "Marty's approach" is already implicit in some aspects
of the
work that has been done on the BPSS and negotiation messages, so it will be
important to discuss and resolve the differences between the too approaches
fairly quickly.
Best,
Kartha
-----Original Message-----
From: Martin W Sachs [mailto:mwsachs@us.ibm.com]
Sent: Friday, September 27, 2002 5:29 PM
To: Kartha, Neelakantan
Cc: ebxml-cppa-negot@lists.oasis-open.org
Subject: Re: [ebxml-cppa-negot] NDD Schema and Sample NDD instance
document
Kartha,
Thank you very much for posting this material. It's a major step forward.
I will study it next week.
Regarding your question in the last paragraph: I believe that the thinking
of the team has evolved to the following: The initial offer is always a CPA
template and an NDD that references the CPA template. When the Party1
wants to make an offer to a Party2 that has published a CPP and an NDD,
Party1 composes a CPA template from its and Party2's CPP. Party1 then
composes a new NDD that references the CPA template and expresses its
negotiability requirements. Party1 SHOULD include Party2's negotiability
requirements (as expressed in its "CPP" NDD) in the new NDD. In other
words Party1 SHOULD offer an NDD which is in some sense the inclusive OR of
its "CPP" NDD and Party2's "CPP" NDD. It is also the responsibility of
Party1 to insert into the CPA template the Start, End, and any other
elements that are present in a CPA but not a CPP.
I have said "Party1 SHOULD include Party2's negotiability requirements"
because I don't think that a SHALL could be enforced. However, Party1
should expect that the negotiation will be much more likely to succeed if
Party2's negotiability requirements are included in the offered NDD.
The above is more or less what you say at the end, except that there is a
single composite NDD (referencing the CPA template) rather than 2 separate
NDDs in the initial offer.
Regards,
Marty
****************************************************************************
*********
Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown Hts, NY 10598
914-784-7287; IBM tie line 863-7287
Notes address: Martin W Sachs/Watson/IBM
Internet address: mwsachs @ us.ibm.com
****************************************************************************
*********
"Kartha,
Neelakantan" To:
ebxml-cppa-negot@lists.oasis-open.org
<N_Kartha@stercom cc:
m.com> Subject: [ebxml-cppa-negot]
NDD Schema and Sample NDD instance document
09/27/2002 05:51
PM
Here is the promised NDD schema and a sample NDD instance document that
conforms to this schema. The NDD
instance document contains the first 15 or so elements in the spreadsheet
that we filled earlier this year. The elements
that are represented are different enough in their negotiability
characteristics, so that the NDD schema captures all
of the negotiation patterns I had identified earlier (in the document
titled
"Patterns in the negotiability of elements" that
I had posted to the list in June 2002.)
I have added comments on the NDD schema and instance document in the hopes
that people will read them. Please
send comments to me and to the list.
The NDD schema is based on a skeleton schema that Dale Moberg had sent to
me---however, note that I have made several changes and additions.
What remains to be done:
1. Flesh out the NDD instance document more. Doing this might require
additions/changes to the schema. However, in many (most?) cases, what is
already in the schema should suffice.
2. Discuss whether the approach proposed here is appropriate/good enough.
I noticed one issue while doing this work. There are some elements (such as
Start/End etc.) that are present only in the CPA. Assuming that one starts
out with two CPPs, the two initial NDDs point to these two CPPs. The
question then is : how is the negotiation of these elements, present only
in
the CPA, to be done, since the NDD does not contain any references to them?
An approach is: first finish the negotiation of the CPPs, form a
preliminary
CPA, with some arbitrary values for these elements. Then form two NDDs for
this CPA, focusing on elements that are present only in the CPA.
Comments?
Best regards,
Kartha
<<NDD1.xsd>> <<sample_NDD.xml>>
#### NDD1.xsd has been removed from this note on September 27 2002 by
Martin W Sachs
#### sample_NDD.xml has been removed from this note on September 27 2002 by
Martin W Sachs
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