OASIS Web Services Reliable Exchange (WS-RX) TC

Call for Participation: OASIS Web Services Reliable Exchange (WS-RX) Technical Committee

Date:      Tue, 03 May 2005 20:01:19 -0700
From:      James Bryce Clark <jamie.clark@oasis-open.org>
To:        members@lists.oasis-open.org, tc-announce@lists.oasis-open.org
Subject:   OASIS TC Call for Participation: OASIS Web Services Reliable Exchange (WS-RX) TC

A new OASIS technical committee is being formed. The OASIS Web Services Reliable Exchange (WS-RX) Technical Committee has been proposed by the members of OASIS listed below. The proposal (below) meets the requirements of the OASIS TC Process [1]. The TC name, statement of purpose, scope, list of deliverables, audience, and language specified in the proposal will constitute the TC's official charter. Submissions of technology for consideration by the TC, and the beginning of technical discussions, may occur no sooner than the TC's first meeting.

This TC will operate under our 2005 IPR Policy [2]. The eligibility requirements for becoming a participant in the TC at the first meeting (see details below) are that:

you must be an employee of an OASIS member organization or an individual member of OASIS
the OASIS member must sign the OASIS membership agreement (see [3])
you must notify the TC chair of your intent to participate at least 15 days prior to the first meeting, which members may do by using the "Join this TC" button on the TC's public page at [4]
you must attend the first meeting of the TC, at the time and date fixed below

Of course, it also will be possible to join the TC at a later time.

Standards always are improved by broad participation. Non-OASIS members who wish to participate may contact us about joining OASIS [3]. Our rules and structure are designed to promote inclusiveness. We look forward to assisting parties interested in joining the community of implementers, technologists, academics, and end-users working on OASIS standardization projects. All also are welcome to take advantage of the public resources maintained for each TC: a mail list archive, document repository and public comments facility, all of which will be available via the TC's public home page at [4]. Archives of the TC's mail list and public comment lists, as with all OASIS TCs, will be visible at [5].

Further information generally related to the topic may be found on the Cover Pages at:

http://xml.coverpages.org/reliableMessaging.html

Please feel free to forward this announcement to any other appropriate lists. OASIS is an open standards organization; we encourage your feedback. JBC

James Bryce Clark
Director, Standards Development, OASIS
jamie.clark@oasis-open.org

[1] http://oasis-open.org/committees/process.shtml
[2] http://www.oasis-open.org/who/intellectualproperty.php
[3] See http://www.oasis-open.org/join/
[4] http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ws-rx
[5] http://lists.oasis-open.org/archives/

Charter of the Technical Committee

Name

OASIS Web Services Reliable Exchange Technical Committee (WS-RX)

Purpose

The purpose of the OASIS Web Services Reliable Exchange (WS-RX) Technical Committee (TC) is to define a protocol for reliable message exchanges between two Web services, through continued development of the Web Services Reliable Messaging specification [1] submitted to the TC as referenced in this charter and to define a mechanism by which Web services express support for reliable messaging as well as other related useful parameters. This mechanism will be based upon the Web Services Reliable Messaging Policy Assertion ("WS-RM Policy") specification [2] submitted to the TC.

TC Scope

The TC will accept as input the February 2005 Version 1.0 of the WS- ReliableMessaging [1] and WS-RM Policy [2] specifications (the Input Documents) from BEA Systems, IBM, Microsoft, and TIBCO Software. Other contributions and changes to the input documents will be accepted for consideration without any prejudice or restrictions and evaluated based on technical merit in so far as they conform to this charter. OASIS members with extensive experience and knowledge in these areas are particularly invited to participate.

The scope of the TC's work is to continue development and refinement of the input documents to produce as output modular specifications that standardize the concepts, WSDL documents and XML schema renderings required to provide reliability assurances to message exchanges between two parties that conform to the specifications.

Reliable messaging systems can generally be described using a four agent model. In this model there is an Application Source, a Reliable Messaging Source that acts on behalf of the Application Source, an Application Destination and a Reliable Messaging Destination that acts on behalf of the Application Destination. Message Transfer is the function of moving messages from a Reliable Message Source to a Reliable Messaging Destination. This TC will provide protocols for the reliable message transfers that occur between Reliable Messaging Sources and Reliable Messaging Destinations. The TC will not develop additional mechanisms by which a Reliable Messaging Source captures messages from an Application Source or mechanisms by which a Reliable Messaging Destination delivers messages to an Application Destination.

A reliable message transfer is one in which certain reliability assurances exist between two parties even in the presence of a variety of failures. There can be multiple, concurrent and independent reliable exchanges between two parties. Reliability assurances make statements about the type of reliability provided to a message exchange.

The specifications will define a set of basic concepts required for the correct functioning of message exchanges with reliability assurances. The specifications will render these concepts as a specific set of restrictions over SOAP messages including XML schemas and WSDL documents.

The specific reliability assurances in the scope of the TC are:

At Least Once: Messages are transferred at least one time or an error is raised on at least one of the endpoints. It is possible that some messages are transferred more than once.
At Most Once: Messages are transferred at most one time or an error is raised on at least one of the endpoints. It is possible that some messages are not transferred.
Exactly Once: Messages are transferred at least one time and at most one time or an error is raised on at least one of the endpoints.
Ordered: Messages are transferred in the order in which they are sent.

These reliability assurances can be combined and certain combinations are of particular interest due to their widespread application: Exactly Once and Ordered (also referred to as Exactly Once Ordered).

The specifications developed by the WS-RX TC will define mechanisms that support and allow the implementation and expression of reliability assurances, at most once, at least once, exactly once, ordered, and will not define mechanisms for applications to manifest reliability assurances.

The specifications developed by the WS-RX TC will define elements and relationships among elements that enable the implementation of the following functions which support the reliability assurances in the scope of the TC:

Reliable establishment and teardown of one or more independent shared contexts between two parties within which reliability assurances apply to one-way or two-way messaging
A mechanism which two parties can use to perform one-way or two-way reliable messaging within a reliable context
Ensures timely destination amnesia detection. Destination amnesia is the condition resulting from catastrophic failure in which a Destination loses the shared context required by reliability assurances.
At Most Once reliability assurances even in the case of Destination amnesia
Efficient message retransmission and acknowledgment
Duplicate message detection
Detection of out-of-order messages and discovery of the correct order of messages
Unique identification of messages within a reliable context
Acknowledgement of all messages within a reliable context
RM protocol violation detection and the raising and transmission of related fault information
Efficient preservation of the integrity of reliable contexts by composition with WS-Security or other SOAP security mechanisms
Expression of support for the specifications using the WS-Policy Framework [9] and binding of that policy to a WSDL port
A binding of the reliable messaging protocol elements to SOAP 1.1 and SOAP 1.2

The specifications will uphold the basic principles of other Web services specifications of independence and composition and must be composable with the other specifications in the Web services architecture, such as WS-Security [3], WS-Trust [4], WS-SecureConversation [5], WS-Addressing [6], SOAP 1.1 [7], SOAP 1.2 [8], bindings of SOAP 1.1/1.2 to HTTP, WS-Policy [9], WSDL 1.1 [10] and WSDL 2.0 [11]. The TC will also take into consideration applicable work, such as the WS-I Basic Profile [12]. The "Secure, Reliable, Transacted Web Services: Architecture & Composition" white paper [13] published in 2003 provides information on the Web services architecture.

If an above specification is outside of a standardization process at the time this TC moves to ratify its deliverables, or is not far enough along in the standardization process, any normative references to it in the TC output will be expressed in an abstract manner, and the incarnation will be left at that time as an exercise in interoperability.

While composition with other specifications is a goal of the TC, it is also a goal to leave the specifics of how that composition is achieved outside the scope of the RM specifications.

Each of the protocol elements will use implementation and language neutral XML formats defined in XML Schema [14].

Out of Scope

The following is a non-exhaustive list. It is provided only for the sake of clarity. If some function, mechanism or feature is not mentioned here, and it is not mentioned in the Scope of Work section either, then it will be deemed to be out of scope.

The TC will not define a mapping of the functions and elements described in the specifications to any programming language, to any particular messaging middleware, nor to specific network transports.

The elements and/or mechanisms the TC defines must be independent of issues and considerations that do not affect an interoperable reliable messaging protocol.

Specifically: the TC is not concerned with binding the specifications to specific underlying transports.

The TC and the specifications that it produces do not address considerations, such as durability related to Sources' and/or Destinations' ability to satisfy reliability assurances.

Except for the elements directly related to the functions in the scope of the specifications, the TC will not prescribe the format of messages that are transferred reliably according to the specifications.

The TC will make no assumptions about the location of Application Sources relative to RM Sources and Application Destinations relative to RM Destinations.

The TC will not attempt to define concepts or renderings for functions that are of wider applicability including but not limited to:

Security (Encryption, Integrity and Authentication)
Addressing
Policy languages and frameworks
Routing
Transactions and Compensation

Where required these functions are achieved by composition with other Web services specifications.

The TC will not attempt to define functionality duplicating that of any normatively referenced specification in the input WS-ReliableMessaging or WS-RM Policy specifications. If the referenced specification is outside of a standardization process at the time this TC moves to ratify its deliverables, or is not far along enough in the standardization process, any normative references to it in the TC output will be expressed in an abstract manner, and the incarnation will be left at that time as an exercise in interoperability.

Deliverables

The TC has the following set of deliverables.

A revised Web Services Reliable Messaging Protocol specification. Committee Specifications are scheduled for completion within one year of the first TC meeting.

A revised Web Services Reliable Messaging Policy Assertion specification. Committee Specifications are scheduled for completion within one year of the first TC meeting.

These specifications will reflect refinements, corrections or material technological improvements with respect to the input documents and in accordance with this charter.

Ratification of the above specifications as OASIS Standards, including a brief period to address any errata, will mark the end of the TC's lifecycle.

The TC may choose to vary the number of the specification documents and their titles.

IPR Mode

This TC will operate under the "RF (Royalty Free) on RAND Terms" IPR mode as defined in the OASIS Intellectual Property Rights (IPR) Policy, effective 15 April 2005.

Audience

The anticipated audience for this work includes:

Vendors offering Web services products
Other specification authors that need reliable message delivery for Web services
Software architects and programmers, who design, write or integrate applications for Web services
End users implementing Web services-based solutions that require an interoperable, composable reliable messaging solution

Language

TC business will be conducted in English.

Additional Information

Non-normative information regarding the TC

Similar or Applicable Work

The following work may be relevant to this WS-RX TC:

Similar Work

OASIS Web Services Reliable Messaging TC. The WSRM TC has a similar goal to that of WS-RX; to specify reliable message delivery for Web services. However, the WSRM TC has a fundamentally different view with regard to scope of the specification, required functions, policy, and Web services architecture composability.

OASIS ebMS TC. The ebMS TC has as part of its scope a similar goal to that of WS-RX. However, it has a fundamentally different view with regard to scope, QoS, required functions and Web services composability.

The proposers of this TC recognize there are different reliability approaches in the industry and believe that the defined Scope of Work of this TC addresses many functional use cases of these parallel efforts. The proposers of this TC seek involvement from the authors of WS-Reliability in particular, and the contribution of their expertise and experience, and intend to work in harmony with them in the creation of the product of this technical committee.

Applicable Work

OASIS Web Services Security TC. WS-RX will ensure that its specifications compose with the WSS TC specifications.

W3C Web Services Addressing WG. WS-RX will utilize the WS-Addressing functions where appropriate and avoid creating overlapping functions.

The TC may decide to establish liaisons with other groups as needed. Responsibilities for such liaison will be defined by the TC at that time.

Anticipated Contributions

The current WS-Reliable Messaging [1] and WS-RM Policy [2] specifications, as published February 2005 by BEA, IBM, Microsoft, and TIBCO Software are expected to be contributed to this TC.

First Meeting

The first meeting of the WS-RX TC will be a face to face meeting held in Palo Alto, California, USA on Thursday, June 23 from 9:00 am to 5:30 local time and Friday June 24 from 9am to 12pm local time. This meeting will be sponsored by SAP.

Ongoing Meeting Schedule

It is anticipated the WS-RX Technical Committee will meet via teleconference every week at a time determined by the TC members during the TC's first meeting. It is anticipated that the WS-RX Technical Committee will meet in face to face every quarter at a time and location to be determined by the TC members. Actual pace of face to face and teleconference meetings will be determined by TC members.

One of the proposers, as listed below, will sponsor the teleconferences unless other TC members offer to donate their own facilities. If no other TC proposers offer to sponsor teleconference facilities, Microsoft will donate their facilities.

TC Proposers

The following eligible individuals are in support of this proposal: