Keywords: reliable messaging, WS-ReliableMessaging, WSRM, SOA, Service-oriented Architecture
Biography
Thomas Erl is the President and Chief Architect of XMLTC Consulting Inc. (www.xmltc.com), a consulting firm in Vancouver specializing in the delivery of service-oriented and XML-centric solutions. He recently authored "Service-Oriented Architecture: A Field Guide to Integrating XML and Web Services" for Prentice Hall/PTR. This book was formally endorsed by IBM and Microsoft, became a bestseller on Amazon's Top 25 Computer Books chart, and is being translated into Chinese. Thomas is currently writing "Service-Oriented Architecture: Concepts and Technology", due for release in 2005 (for more information visit www.serviceoriented.ws). Thomas has published over 30 papers, and established an integration framework for XML and Web Services. He also maintains a series of resource Web sites for XML and Web services. For more information, visit Thomas' bio site at www.thomaserl.com/technology/.
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 WS-* specifications that have emerged position SOAs 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.
One area being addressed by this second-generation of Web Services standards is reliable messaging. In order for a solution to be truly robust, its communications framework must be failsafe. Within service-oriented architectures, this requires a system for the guaranteed delivery of a message, which includes a way of communicating delivery failures. WS-ReliableMessaging provides such a system, along with a set of policies that can be used to support delivery-related business rules.
This presentation discusses the increasingly important role of WS-ReliableMessaging.
The following specific topics are covered:
Acknowledgements
WS-ReliableMessaging establishes a standard method of notifying the message sender of the success or failure of the delivery. This notification is accomplished through an acknowledgement that is sent either as a separate message, or as an embedded construct within the response message generated by the original message recipient. Acknowledgement
Sequences
To implement a system for the reliable delivery of messages, WS-ReliableMessaging requires that SOAP header blocks be embedded with a number of message attributes hosted within a container called a sequence. The information within a sequence is used to identify and process messages.
Delivery Assurances
To enforce certain polices relating to the required reliability guarantees, WS-ReliableMessaging uses delivery assurances. The different types of delivery assurances provided by the WS-ReliableMessaging specification are discussed.
Polices
The WS-Policy framework, as it relates to WS-ReliableMessaging delivery assurances, is covered. This framework consists of a set of specifications that allow for the description of policies, as well as a standard means of attaching them to Web services.
Since this talk was waitlisted, no paper was prepared for the proceedings.
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