[graap-wg] scoping thoughts

[Karl Czajkowski]

The recent thread between Jon and me has given me some added clarity
as to the framing and scoping of the agreement problem space.  Please
consider the following as my view of how the agreement concept space
is populated and which of these concepts are in or out of scope of
WS-Agreement.

Note, I have CAPITALIZED certain keywords that I think are the
important concepts we need to tease apart.  I thought this would be
easier than reading HTML or LaTeX tags in the ASCII. :-)

Do we have a concensus on these concept definitions and/or scoping? If
so, I would be happy to try to rejigger the specification introductory
text to better communicate this information. If not, I think it is
crucial that we iterate on this until we do have consensus!

karl



In designing and presenting WS-Agreement, it is useful to define the
concept space of agreement.

1. Agreement is a RELATIONSHIP between two parties.

The core concept of WS-Agreement is that agreement is a relationship
between two parties in which they are obligated to act in certain ways
according to a notion of reciprocity. These obligations are
necessarily domain-specific, and the reciprocity does not imply
symmetry: one party may be obligated to complementary behaviors such
as paying for service rather than returning service in kind.

The semantics of this relationship are out of scope of WS-Agreement
because they are domain-dependent.


2. WS-Agreement defines a PROTOCOL for establishing agreement.

The fundamental resource management challenge being addressed by
WS-Agreement is the standardization of a signaling protocol to allow
temporary two-party agreement relationships to be established,
maintained, and retired in a decentralized, multi-party, distributed
system. These agreements modify, or parameterize, the behavior of the
parties towards one another while respecting global system constraints
on available resources etc.

The mechanics and syntax of this protocol, except for the embedded
domain-specific content, are within scope of WS-Agreement.


3. The WS-Agreement protocol encodes an agreement DOCUMENT which
   represents the nature of the relationship in order to facilitate
   agreement establishment.

At minimum, WS-Agreement requires that one party OFFERs to establish
agreement with an embedded agreement document. The other party must
ACCEPT or REJECT this offer to establish (or not) the agreement
relationship and bind the two parties.

The syntax of this document, except for the embedded domain-specific
content, are within scope of WS-Agreement.


4. The agreement document also is useful to represent the STATUS of
   the relationship for purposes of general system introspection and
   management.

The presentation of the document and associated advisory metadata is
within scope of WS-Agreement.


5. Another goal in some trust and accounting environments is to be
   able to DEMONSTRATE that an agreement relationship exists.

The ability to demonstrate the existence of an agreement relationship
may be valuable when resolving conflicts or in order to increase
confidence in an agreement relationship between parties enjoying
limited trust in one another.  This demonstration of agreement can be
facilitated by bilateral exchange of agreement documents with
signature or some other means of visibility to a third party arbiter,
whereas mere establishment of agreement between trusting parties
may be accomplished with less data exchange.

The ability to exchange agreement documents bilaterally is within
scope of WS-Agreement, while the specifics of how one might sign such
documents is out of scope and only supported through extension
mechanisms.


6. Another goal is to be able to MEASURE the satisfaction of an
   agreement relationship.

The measurement or validation of behavior of a party may be performed
for different reasons by each party in the agreement and/or a third
party.

  a) A party may measure its own behavior in order to adaptively stay
     within the terms of the agreement, to know whether it has done
     so, or to ADVISE the other party when the relationship cannot be
     satisfied.

  b) A party may measure the other party's behavior in order to
     RATE the reliability or trustworthiness of that party.

  c) A third party may AUDIT either party's behavior in order to
     facilitate resolution of conflicts (possibly in combination with
     demonstration of the agreement relationship).

The self-monitoring behavior of an agreement party is out of scope of
WS-Agreement, but the ability to advise other parties of past or
imminent status changes is within scope.

The monitoring of behaviors by the second or third party is out of
scope of WS-Agreement. [Should an ability to advise a party of
external observations of its behavior be in scope? It is not
currently.]



-- 
Karl Czajkowski
karlcz at univa.com