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Basic configuration and usage of WebSphere MQ 7.1 Multicast

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The objective of this technical document is to describe in detail how to perform a basic configuration and how to use the new publish/subscribe functionality which was introduced in WebSphere MQ 7.1: Multicast.


This new feature requires a Full Duplex client-server connection channel, which means that the SHARECNV attribute must have a value greater than 0.

In order to emphasize that the network multicast is being used, in the examples provided in this techdoc the MCAST attribute for the Topic Objects has a value of ONLY. That is, if the subscriber is receiving messages from the publisher, it is because multicast is actually being used.
In practice, once you have proved that multicast works on your network, you can change the attribute from ONLY to ENABLED, which means that both multicast and non-multicast publishing of messages can be done on the topic.

A set of samples written in C-code are included and which can be used to illustrate how to test the multicast feature:
- publisher and subscriber applications connect to the queue manager,
- publisher publishes 1 message every 2 seconds and the subscriber receives them,
- queue manager is ended with the immediate (-i) and reconnect (-r) flags,
- publisher continues to publish messages and the subscriber continues to receive them.

In addition, a chapter is dedicated to the testing using the following SupportPac, which provides an executable program called "q" (for different platforms) that can be used for testing the multicast feature:

MA01: WebSphere MQ - Q program

1: This new feature is ONLY applicable for C based code. It is NOT supported for Java nor JMS.
2: The references in the MQ 7.1 Information Center for JMS and Multicast are ONLY for an old release of Message Broker and are NOT applicable for the new function introduced in MQ 7.1.

This document is organized as follows

Chapter 1: Introduction and main references
Chapter 2: Configuration
Chapter 3: Compiling the C-code samples
Chapter 4: Testing of C-code samples: non-multicast
Chapter 5: Testing of C-code samples: multicast
Chapter 6: Testing using the SupportPac MA01: Q program
Chapter 7: Configuration to receive pub/sub events

Thanks to Paul Clarke (IBM UK) for his assistance.

Attached files:
- PDF: Configuring and Using WebSphere MQ 7.1 Multicast.pdf
- Zip file with samples: MQ7.1-multicast-samples

PDF: Configuring and Using WebSphere MQ 7.1 Multicast.pdf

Configuring and Using WebSphere MQ 7.1 Multicast.pdfConfiguring and Using WebSphere MQ 7.1 Multicast.pdf

Zip file with samples: MQ7.1-multicast-samples

DISCLAIMER: All source code and/or binaries attached to this document are referred to here as "the Program". IBM is not providing program services of any kind for the Program. IBM is providing the Program on an "AS IS" basis without warranty of any kind. IBM WILL NOT BE LIABLE FOR ANY ACTUAL, DIRECT, SPECIAL, INCIDENTAL, OR INDIRECT DAMAGES OR FOR ANY ECONOMIC CONSEQUENTIAL DAMAGES (INCLUDING LOST PROFITS OR SAVINGS), EVEN IF IBM, OR ITS RESELLER, HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Document information

More support for: WebSphere MQ

Software version: 7.1, 7.5

Operating system(s): AIX, HP-UX, Linux, Solaris, Windows

Reference #: 7024903

Modified date: 22 May 2012