Proceedings

Abstract:

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.