SOA Specifications

Home	Second-Generation (WS-*) Web Services	First-Generation Web Services	Core XML Platform

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The driving motivation behind extending the capabilities of the first-generation Web services framework is to empower service-oriented architectures to represent and even improve upon the range of business functions required for contemporary enterprises.

The army of second-generation Web service specifications that have emerged position SOA as a viable successor to prior distributed platforms. The range of features they offer continues to broaden, as do vendor-sponsored variations of the specifications themselves. The continuing maturity of these specifications and their implementations sets the stage for the viable evolution of a service-oriented enterprise.

Provided below in the left column are links to the WS-* specifications referenced in the SOA books displayed to the right.

Context and Transaction Management

The initial set of Web services technologies lacked the ability to support the structured maintenance of context throughout a service activity. Without an active, stateful context, Web services act independently and cannot support distributed transactions.
The WS-Coordination specification provides a context management system, which is applied to support atomic and long-running transactions, using protocols described in the WS-Transaction specification.
The atomic transaction part of the WS-Transaction specification is superseded by a separate specification titled WS-AtomicTransaction. Similarly, the WS-BusinessActivity specification replaces the corresponding coordination type definition within WS-Transaction.
Referenced Specifications: WS-Coordination WS-Transaction (and the WS-TX TC) WS-AtomicTransaction WS-BusinessActivity
Locations: IBM Microsoft OASIS (WS-TX TC)

Business Process Definition and Execution

In order to compose Web services into a structured workflow, a standard vocabulary is required. The Business Process Execution Language for Web Services provides a process description vocabulary that can be compiled into runtime scripts, executable by middleware products that support orchestration. BPEL4WS (and its successor, WS-BPEL) brings Web services into the realm of enterprise integration.

Referenced Specifications:
WS-BPEL
BPEL4WS

Locations:

IBM (BPEL4WS)

Microsoft (BPEL4WS)

OASIS (WS-BPEL)

Security

Probably the largest gap in the first-generation Web services platform was an absence of any real security standards. Consequently, organizations were reluctant to expose business processes over the Internet.
The WS-Security framework institutes a thorough security model consisting of a stack of complementary specifications. It establishes security measures to protect SOAP messages throughout a message path, and supports the creation of policies and the unification of trust boundaries. The core WS-Security specifications are further supplemented by a series of established XML security specifications.
Referenced Specifications: WS-Security (and the WS-SX TC) WS-Federation WS-SecureConversation WS-Trust XML Encryption XML Signature XKMS XACML SAML WS-I Basic Security Profile
Locations: Microsoft (WS-Security) IBM (WS-Security) W3C (XML Encryption, XML Signature, XKMS) OASIS (WS-Security, SAML) OASIS (WS-SX TC)

Reliability, Routing, and Attachments

In order for a solution to be capable of enterprise-level automation, its communications framework must be failsafe, flexible, and efficient. The following WS-* specifications propose critical features that deal with reliabile delivery, self-governing messaging, and message attachments.

Referenced Specifications:
  WS-ReliableMessaging (and the WS-RX TC)
  WS-Attachments
  SwA
  DIME

Locations:

Microsoft (WS-ReliableMessaging)

IBM (WS-ReliableMessaging)

IBM (WS-Attachments)

OASIS (WS-RX TC)

W3C (WS-Addressing)

Policies and Metadata

Within a service-oriented enterprise, it would be useful to be able to abstract high-level business rules, security rules, and descriptive properties so that they can be applied to groups of services as policies.

The WS-Policy framework consists of a set of specifications that allow for the description of such policies, as well as a standard means of attaching them to Web services. WS-MetadataExchange complements WS-Policy (and WSDL) by providing a standardized means of querying Web services for metadata.

Referenced Specifications:
  WS-Policy
  WS-PolicyAssertions
  WS-PolicyAttachments
  WS-MetadataExchange

Locations:

Microsoft

IBM (WS-Policy)

IBM (WS-MetadataExchange)

W3C (WS-Policy)

Other Referenced Specifications

Referenced Specifications:
  Plain Old XML (POX)
  Representational State Transfer (REST)
  WS-CDL (Choreography Description Language)
  WS-Eventing
  WS-Notification
  WS-RF (Resource Framework)

Locations:

WP (POX)

WP (REST)

W3C (WS-CDL)

Microsoft (WS-Eventing)

IBM (WS-Notification)

OASIS (WS-RF)

SOA Design Patterns
by Thomas Erl

Foreword by Grady Booch.

With contributions from David Chappell, Jason Hogg, Anish Karmarkar, Mark Little, David Orchard, Satadru Roy, Thomas Rischbeck, Arnaud Simon, Clemens Utschig, Dennis Wisnosky, and others.

Web Service Contract Design & Versioning
for SOA
by Thomas Erl, Anish Karmarkar, Priscilla Walmsley, Hugo Haas, Umit Yalcinalp, Canyang Kevin Liu, David Orchard, Andre Tost, James Pasley

SOA Principles
of Service Design
by Thomas Erl

An in-depth guide dedicated to service engineering with a thorough exploration of the design principles that comprise the service-orientation design paradigm (including a comparison with object-orientation).

Service-Oriented Architecture:
Concepts, Technology, and Design
by Thomas Erl

The first "how-to" guide to building SOA, providing coverage of WS-* specifications, .NET and J2EE platforms, and step-by-step processes for service-oriented analysis and design.