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WebSphere Application Server z/OS Default Messaging Availability

Document Author:
Additional Author(s):

Don Bagwell
Michael Stephen

Document ID:


Doc. Organization:

Advanced Technical Sales

Document Revised:


Product(s) covered:

WebSphere Application Server for z/OS; z/OS

Abstract: WebSphere Application Server has a built-in function that provides messaging. It's called the "Default Messaging" function of WebSphere Application Server, and is built on the "SIBus" (Service Integration Bus) structure of WAS. This is available for WebSphere Application Server on all platforms.

On z/OS, WAS z/OS implements the default messaging function in the "Control Region Adjunct" (CRA) address space. That's where the "messaging engine" function resides. In a clustered environment, the default messaging infrastructure can be made highly available.

IBM recently performed a thorough analysis of the default messaging / SIBus / CRA structure and how it operates in a highly available configuration. From this analysis several APARs were created which enhance the availability functionality. This Techdoc provides information on the fixes and enhancements provided in the APARs related to the default messaging.

List and Description of APARs that Address Availability Issues




Planning and Design


IBM System z Family

S/W Pillar(s):





WAS z/OS Default Messaging SIBus ME

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