WS-ReliableMessaging - How it works
WebSphere® Application Server uses WS-ReliableMessaging as part of the transport layer for SOAP over HTTP messages. The message exchange patterns that are supported at the API layer are one-way "fire and forget," or two-way request and reply.
WS-ReliableMessaging became a stabilized feature in WebSphere Application Server Version 8.5.5.
The reliability is provided by reliable messaging middleware that sits between the web service requester and the web service provider. This middleware layer is shown beneath the dotted line in the following diagram, and includes the reliable messaging source and the reliable messaging destination.
- Client-side retransmissions start only after the client starts sending new messages to the service (this situation is true for both one-way and two-way operations).
- Two-way operations that resume cannot drive the response message back to the client application; the message gets back only as far as the inbound sequence on the client.

In the previous diagram, the application source invokes a web service. The sequence of interactions is as follows:
- The invocation is passed to the reliable messaging source.
- The reliable messaging source stores the message and then returns control to the application.
- The reliable messaging source sends the message to the reliable messaging destination.
- After the reliable messaging destination receives the message, it stores it locally and sends an acknowledgement message back to the reliable messaging source.
- The reliable messaging source can now delete its copy of the message.
- The reliable messaging destination can deliver the message to the application destination at any time after it receives it from the reliable messaging source.
要将 Web Service 应用程序配置为使用 WS-ReliableMessaging,请连接包含 WS-ReliableMessaging 策略类型的策略集。此策略类型提供了一系列服务质量:受管持久、受管非持久或非受管非持久。
服务集成总线支持受管服务质量(即,受管持久和受管非持久服务质量)。 对于应用程序和策略集之间的每个连接,可以选择总线与消息传递引擎以用于可靠消息传递协议的状态。