Frank,
The discussion of obligations and permissions reminded me of
other material from early 2009.
Ken
The actions undertaken by participants, whether mediated by services
or in some other way, are normally performed in a social context which defines
the meaning of the actions themselves. We can formalize that context as a social
structure: the embodiment of a particular social context.
The social structure model is important to defining and
understanding the implications of crossing ownership boundaries; it is the
foundation for an understanding of security in SOA and also provides the
context for determining how SOA-based systems can be effectively managed and governed.
Figure 8 Social Structure
Social Structure
A social structure establishes (formally or informally) the
rights and responsibilities of its members, including the relationships and
permissible interactions among members and with non-members.
Any number of participants can be members of a social
structure and a given participant can be a member of multiple social
structures. Thus, there is frequent interaction among social structures,
sometimes resulting in disagreements when the goals of the social structures do
not align.
The goals of the social structure lead to activities to
further those goals and manifests itself in the intent of the social structure
and its members.
Intent
Intent is a willingness by a member of a social structure
to perform actions to achieve a stated goal.
The ways in which intent can be manifested must still fit
within the rules and responsibilities defined by the social structure. The
social structure defines rights and responsibilities which can be categorized
as the following:
Commitment
A commitment is a stated intent regarding the status of a
shared state in the future.
In the future, some fact will be true and a participant has
the current responsibility of ensuring that that fact will indeed be true. A
commitment to deliver some good is a classic example of a fact about the
future.
Permission
A permission is an activity in which the social structure
allows some subset of its members to engage.
A social structure may have criteria before it will give its
members permission to make a commitment. For example, a member may have to post
a bond before that member can engage in an activity that might cause a loss to
others.
Obligation
An obligation is a requirement by the social structure on
some subset of its members to perform activities that will result in a defined
status for certain shared states..
An obligation is most often associated with responsibilities
and may be the counterpart to having certain rights. For example, someone may
have the right to buy a house in a certain neighborhood but the city may impose
obligations that ensure the house is kept in good repair.
Prohibition
A prohibition is an activity in which the social structure
disallows some subset of its members to engage.
The informal social structure of basketball players at a
public gym may decide that certain expressions of language are not permitted
because young children are in the area.
The shared state provides a set of facts against which
commitments can be promised, permissions can be granted, obligations can be
measured, and adherence to prohibitions can be assessed. For example, if, as a
result of interacting with a service, a buyer incurs the obligation of paying
for some good or service, this obligation (and the discharge of it) is
measurable (perhaps by further interactions with the same or other services).
From its various components, rights and responsibilities can
then be collectively defined as
Rights
A right is an activity that is allowed or a stance that may
be adopted in relation to the social structure. It
A right is often in the form of a permission or the allowing
of a commitment, but a social structure may consider it a right to engage in
any activity that is not expressly prohibited. Conversely, a social structure
may consider anything not expressly stated as a right to be prohibited. Having
or exercising a right may subject the social structure member to associated
obligations.
Responsibilities
A responsibility is an activity that is required in
relation to the social structure.
A responsibility is often in the form of an obligation and
may require a commitment on the part of the social structure member. In
general, a social structure may be consider it a responsibility to follow
through on commitments, fulfill obligations, and not engage in prohibited
activities.
1.1.1 Social
Structures and Governance
A social structure may or may not have a formal governance
structure. For example, a group of individuals may agree that every Wednesday
night those who can be at a certain gym will choose teams and play basketball.
There is only a loose understanding, possibly resulting in too many people some
nights and too few on others, but that may be sufficient for the needs of the
participants. A formalization would be to organize a league with identifiable
teams and a schedule of play. This formalization introduces the rudimentary
levels of governance.
Given that SOA mediates important aspect of participant
relationships, it follows that there are rights and responsibilities that
require enforcement by the social structure and that the SOA itself must
reflect the requirements of the social structure itself. In the Reference
Architecture, we are concerned primarily with social structures that reflect
the anticipated participants in SOA-based systems; these are often embodied in
legal and quasi-legal frameworks; i.e., they have some rules that are commonly
understood.
For example, a corporation is a common kind of social
structure, as is a fishing club. At the other extreme, the legal frameworks of
entire countries and regions also count as social structures.
It is not necessarily the case that the social structures
involved in a service interaction are explicitly identified by the
participants. For example, when a customer buys a book over the Internet, the
social structure that defines the validity of the transaction is often the legal
framework of the region associated with the book vendor. This legal
jurisdiction qualification is typically buried in the fine print of the service
description.
The models for governance are introduced under the Owning
SOA view, but here we discuss consistency with the model for social structure.
Governance
Governance is establishing the necessary framework and
processes to formalize the rights and responsibilities defined by the social
structure.
The motivation for establishing a social structure is to
organize a group of participants around predictable rules and responsibilities,
and to have a system in which there can be enforcement of the same.
There are numerous parallels between the social structure
model in Figure 8 and the governance models in the Owning a SOA view:
- For
formal governance, the collective social structure identifies Leadership
as a focal point.
- Whereas
the less formal social structure defines expectations in the form of
rights and responsibilities and an appropriate level of enforcement (e.g.
someone could become a social outcast), the more formal Leadership puts
governance mechanisms in place so there are safeguards for clarity and
fair treatment.
- The
parallels between a general social structure and formal governance proceed
through to ad hoc agreements vs. formal management and commonly desired
real world effects.
As a participant can be a member of more than one social
structure, so a participant can fall under more than one governance structure.
These may be hierarchical or parallel chains with overlapping and possibly
inconsistent goals.
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Dr. Kenneth Laskey
MITRE Corporation, M/S
H305
phone: 703-983-7934
7515 Colshire
Drive
fax: 703-983-1379
McLean VA 22102-7508