Proposed Draft Charter for Choreography WG

Hi,
    I have attached the proposed charter for a Choreography WG. This draft 
represents the WS Arch WG consensus recommendation that was taken on Nov 7, 
2002.
    cheers,
     jeff

/ | %5CArchitecture%5C

Web Services Choreography Working Group Charter Proposal

- Goals and Scope of the
Web Services Choreography Working Group

- Inputs

- Deliverables

- Out of Scope

- Qualities

- Mappings to Programming
Languages

- Schedule

- Relationships
with Other Work

- W3C Groups and
Activities

- External Groups

- Participation, Meetings,
and Logistics

- Participation

- Email Communication

- Group Home Page

- Meetings

- Resources

- W3C Team Involvement

- Intellectual Property

- References

1 Goals and Scope of the Web Services Choreography
Working Group

It has become clear that a next step in the evolution
of Web services will be the ability to compose and describe the relationships
between Web services. Although differing terminology is used in the
industry, such as orchestration, collaboration, coordination, conversations,
etc., the terms all share a common characteristic of defining linkages
and usage patterns between web services. For the purpose of this document,
and without prejudice, we use the term choreography as a moniker
to denote this space.

Many presentations at the W3C Workshop on Web services of 11-12
April 2001 pointed to the need for a common interface and composition
language to help address choreography. The Web Services Architecture
Requirements working draft created by the Web Services Architecture
WG also lists the idea of Web service choreography capabilities as a Critical
Success Factor, in support of several different top-level goals for the
nascent Web services architecture.

Two technical submissions -- WSCL[6] , and
WSCI[2] , have recently been published by the W3C
as Technical Notes. There are other industry efforts in the area of choreography
languages, such as BPML[7] (defined by BPMI.org),
BPSS[8] (defined by ebXML.org), IBM's

WSFL[9] , MSFT's XLANG[10] ,
and IBM/MSFT/BEA's BPEL4WS[3] and their companion
specifications WS-Coordination[4] and WS-Transaction[5] ), etc.

The problems posed by the lack of a widely adopted choreography
specification, the current proliferation of overlapping work,
and the time required to complete this effort merit the chartering a new
W3C WG now. This WG should address the choreography space encompassed
by the input documents and deliverables. This WG should also coordinate
with other WGs within the Web Service Activity, with the aim of developing
an interoperable and open standard for Web service choreography

WSDL has proved very useful for describing a single service. Currently
complex natural language describing the obligations of the participants
detailing how to use a service (sequencing, state management, etc.) have
to accompany a WSDL description. The next step is to partially replace
these somewhat imprecise instructions with precise language. This will simplify
the daunting task companies now face when trying to use web services to
integrate their business processes. In a B2B context such a specification
could reduce the cost of integrating with new trading partners and responding
to changes in existing interfaces. In addition, creating a standard
language to describe the relationships between document exchanges will be
helpful to other standards bodies, such as RosettaNet or CIDX, giving them
a standard infrastructure for message choreography and enabling them to
focus on the core competencies relevant to their domain.

The Web Services Choreography Working Group, part of the Web Services Activity , is chartered to
create the definition of a choreography, language(s) for describing
a choreography, as well as the rules for composition of, and interaction
among, such choreographed Web services. The language(s) should
build upon the foundation of the Web
Service Description Language (WSDL).

1.1 Inputs

The Working Group shall start by considering the various input documents
listed below and refine the scope and factorization of the choreography
space. The Working Group is also expected to be aware of other work
that has been published in this area, although it is not a formal input.

The Working Group shall consider, at a minimum, as input:

- Web
Services Architecture [1]

- BPEL4WS
[3] (if made available to the W3C by its owners)

- WSCI [2]

- W3C Choreography Workshop [date tbd]

1.2 Deliverables

The Working Group shall produce the following deliverables:

- A requirements document. including a
detailed description of the factorization of the Choreography space

- Usage scenarios

- One or more specifications of choreography
language(s) and its XML Schema.

- A Primer

- A test suite

A test suite
will be developed by the Working Group in order to assess advancement to
Proposed Recommendation stage and to promote interoperability. The Working
Group is expected to demonstrate two interoperable implementations during
the Candidate Recommendation phase. Conformance requirements must be
clearly stated in the specification produced.

The choreography specification(s) shall define (at a minimum) the behavior
and language constructs for the following key concepts:

- Composition features

- The ability to define a choregraphy
as a web service, i.e. a recursive composition model.

- Definition of the choreography's externally
observable behavior.

- Ability to specify externally defined constraints.

- Ability to represent stateful choreographies.

- Definition of the identity of a choreography
instance.

- Lifecycle management (e.g. creation,
termination, etc.).

- Message exchange interactions between web services
(e.g. receive, invoke, etc.).

- Behavior definitions (e.g. sequencing, looping
concurrent execution, etc.).

- Scoping rules.

- Activities.

- Associations

- Roles based on web service use.

- Linkages between web services.

- References to web services.

- Message exchanges

- Conversations - correlated message
exchanges that define interactions between web services.

- Correlations and their life cycle
management.

- Correlation relationships
with choreography instances and state.

- State Management

- Definition, manipulation, and query
capabilities

2 Out of Scope

2.1 Qualities

It is obvious that transactions, security, reliability,
availability, and other such qualities are intimately related with Web
service choreography, some more than others. It is not the goal of this
group to define these mechanisms, but it must clearly articulate the
boundaries.

2.2 Mappings to Programming Languages

Web services are composed of interfaces to applications, which can be written
in different programming languages. The purpose of the Working Group is
to provide a framework that supports a wide variety of applications and programming
languages, and is not geared towards any programming language. Given the
wide variety of programming languages, the Working Group should not define
mappings to any programming languages.

3 Schedule

These are subject to revision due to editorial needs and external scheduling
issues; updates will be negotiated with the related groups and recorded on the Web Services Choreography Working Group home
page . Meeting dates are mentioned here for planning purposes.

December 2002

Working Group chartered

January 2003

W3C Workshop on Web Services
Choreography

February 2003

First Working Group face-to-face meeting

April 2003

First requirements document
for Web services choreography

July 2003

First Working Draft of the
Web services choreography specification.

January 2004

Candidate Recommendation
for the Web services choreography specification.

June 2004

Recommendation for the Web
services choreography specification.

June 2004

Working Group ends

The target duration of the Working Group is 2 years, through June 2004.
Experience suggests that 6 months of contingency should be allowed to
accommodate unexpected obstacles to progress.

4 Relationship with Other
Work

4.1 W3C Groups and Activities

XML and XML derived activities have become a strategic technology in W3C
and elsewhere. Each deliverable of any Working Group must satisfy the
dependencies from other W3C Working Groups before it can advance to Candidate
Recommendation.

Web Services Activity

The Web Services
Architecture Working Group has been chartered to create a document
describing the architecture of Web services. A working draft of this document
is now available. The Working Group will continue to take this document
into account while designing the choreography language in order to make
sure that Web services can be deployed in an optimal way, as recommended
by the Web Services Architecture Working Group.

The Working Group must describe services
accessible via WSDL 1.2 defined by the Web
Services Description Group .

It is expected that other Working Groups will
be formed to deal with different aspects of the Web services architecture.
The Working Group will closely coordinate its work with any other Working
Group formed within the Web Services Activity and generally in the Web
services area, as well as with relevant Working Groups outside of the
Web Services Activity.

The Working Group will participate in the Web Services Coordination Group .

XML Activity

The typing of the messages must be possible
using XML Schema . While no dependencies
other than the one with the XML Schema Working Group are presently identified,
the Web Services Description Working Group should be prepared to coordinate
with the XML Activity as necessary.

QA Activity

The Working Group will develop a primer and
a test suite in order to improve the quality of the documents produced
and their implementations.

Internationalization
Activity

The Internationalization Working Group will
review work to ensure that principles developed by that group are consistently
applied.

Web Accessibility Initiative

The work of the Working Group will be subject
to review by this project.

XForms Working Group

XForms can be seen as providing a user interface
for Web services. The Working Group will call for requirements from
the XForms Working Group, if any.

4.2 External Groups

The Web Services Choreography Working Group should liaise with at least
the following groups outside W3C (see also W3C liaisons with other organizations ):

ebXML Joint Co-ordination Committee

The ebXML initiative was a joint activity of
UN/CEFACT (the United Nations body
responsible for UN/EDIFACT ) and
OASIS (Organization for the
Advancement of Structured Information Standards). Their charter was to develop
an XML-based infrastructure for electronic commerce, with a particular
focus on making connections between EDI and XML. While the original ebXML
initiative's charter ended in May of 2001, the work transitioned to the
respective sponsoring organizations (OASIS and UN/CEFACT) under the auspices
of an MOU signed by the two in May of 2001.

UN/CEFACT (United Nations Centre for Trade Facilitation
and Electronic Business)

The International Trade
and Business Processes Group (TBG) maintains ebXML Business Process
Specification Schema, a metamodel for business processes that is part
of the ebXML framework.

BPMI.org

BPMI.org is a non-profit
working towards establishing standards for the management of business
processes that span multiple applications, corporate departments and
business partners.

Workflow Management Coalition

The
Workflow Management Coalition, founded in August 1993, is a non-profit,
international organization of workflow vendors, users, analysts and university/research
groups. The Coalition’s mission is to promote and develop the use of
workflow through the establishment of standards for software terminology,
interoperability and connectivity between workflow products.

5 Participation, Meetings, and Logistics

5.1 Participation

To join the Web Services Choreography Working Group, please follow the
instructions of section 4.2.3
of the Process Document, sending email to the Working Group Chair and
the W3C Team contact. The nomination must include explicit agreement
to this charter, including its goals, an IPR disclosure
and the level of effort required of the representative.

Each Member organization may have at most two participants in the Working
Group. Only Working Group participants may engage in formal votes on
substantive issues. When a formal vote is required, each Member organization
or group of related Members is allowed one vote, even though the Member
may have several participants in the Working Group.

The W3C Team is expected to have at most two participants in the Working
Group (including the Team contact). When a formal vote is required,
the Team is allowed one vote.

Membership is also open to invited experts from the community,
selected by the Chair in order to balance the technical experience of
the group.

Each participant should expect to spend one day per week on work for this
Working Group.

5.2 Email Communication

The Working Group will utilize a public mailing list <[email protected] > for its technical
email communications. It is referred to in the rest of this document
as the Working Group mailing list.

A Member-only mailing list <[email protected] >
is available for administrative purposes only.

5.3 Group Home Page

The Working Group has a home page that
records the history of the group, provides access to the archives, meeting
minutes, updated schedule of deliverables, membership list, and relevant
documents and resources. The page is available to the public and should
be maintained by the Chair in collaboration with the W3C Team contact.

5.4 Meetings

The Working Group will have distributed and face-to-face meetings.

A one- to two-hour Working Group distributed meeting will be held every
week. When necessary to meet agreed-upon deadlines, distributed meetings
may be held twice a week.

The Working Group may schedule face-to-face meetings in a manner that
maximizes co-location with events that Working Group members would be attending
anyway.

Participation in meetings (distributed or face-to-face) is limited to
participants in good standing and individuals invited at the discretion of
the Chair to specific meetings.

Decisions taken in meetings must be announced on the Working Group mailing
list. Observers may take part in decision-making at the discretion of
the Chair.

Meeting records must include attendance, the results of group decisions,
and action items. They must be made publicly available except for non-technical
issues that do not directly affect the output of the Working Group.
The Chair will decide which issues are not made public.

5.5 Resources

To be successful, we expect the Working Group to have approximately 20
to 30 active participants. A large public review group that will participate
in the mailing list discussions is expected.

The Chair for the Web Services Choreography
Working Group will be XXXX.

5.6 W3C Team Involvement

The W3C Team expects to dedicate the time of the services of one Team Contact , full-time, for the 2-year
duration of the Working Group. XXXX will provide this effort.

5.7 Intellectual Property

W3C promotes an open working environment. Whenever possible, technical
decisions should be made unencumbered by intellectual property right
(IPR) claims. W3C's policy for intellectual property is set out in section 2.2 of
the W3C Process document .

Members
of the Working Group are expected to disclose any intellectual property
they have in the area. This WG will work on a royalty-free
basis, as defined in the W3C Current Patent Practice
document. The Working Group is thus obliged to produce a specification which
relies only on intellectual property available on a royalty-free basis.

If it proves impossible to produce specifications implementable on a
royalty-free basis, then a Patent Advisory Group will be launched as described
in the W3C Current
Patent Practice document.

Members disclose patent and other IPR claims by sending email to <[email protected] >, an archived mailing
list that is readable by Members and the W3C Team. Members must
disclose all IPR claims to this mailing list but they may also copy other
recipients. IPR disclosures are expected to be made public; Members should
specify if their disclosure is confidential.

6 References

[1] http://www.w3.org/2002/ws/arch/2/08/wd-wsa-arch-20020821.html

[2] http://www.w3.org/TR/wsci/

[3] http://www-106.ibm.com/developerworks/library/ws-bpel/

[4] http://www-106.ibm.com/developerworks/library/ws-coor/

[5] http://www-106.ibm.com/developerworks/webservices/library/ws-transpec/

[6] http://www.w3.org/TR/wscl10/

[7] http://www.bmpi.org

[8] http://www.ebxml.org/specs/ebBPSS.pdf [9] http://www-3.ibm.com/software/solutions/webservices/pdf/WSFL.pdf

[10] http://www.gotdotnet.com/team/xml_wsspecs/xlang-c/default.htm http://www.ebxml.org/specs/ebBPSS.pdf

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Team Contact: XXXXX