Oracle Application Server OracleAS 10.1.3 & multicast communications

How to communicate changes

Each release of the Oracle Application Server provides new capabilities, better stability, and increased usability.  The latest version of OracleAS, 10.1.3, is currently only available in the J2EE configuration.  If you want to use any other edition of the application server, you will need to use version 10.1.2.  However, even if you already use an earlier version, looking at the new capabilities of the latest J2EE edition will give you a preview of the great new features to come.  In this article we will focus on how the 10.1.3 Application Server uses multicast to replicate state information, cluster instances, and communicate between instances.

What is Multicast? 

The term multicast basically refers to broadcasting a message across the entire network, rather than just to one other computer.  In a normal configuration, if server A is hosting an application and the application is no longer available, server A will notify the requesting server B that the application is no longer available.  Then server B will respond that it understands, and it will route all further request to another server where the application is still running.  In the case of a multicast, server A will simply announce to all the servers in its topology list that the application is shutting down.  In some cases servers do not respond to a multicast, so server A may not wait for a reply.   Server B will receive the notification from server A and route request to another server. 

Multicasting was not invented by Oracle and is used in a number of applications on the Internet.  Because it allows one notification to be used by multiple recipients, it is an effective and efficient method to utilize in one-to-many communication.  Streaming audio/video and conferencing systems use multicast to efficiently deliver content to multiple users making efficient use of network resources.  There are standard ranges of IP address established for different types of multicast system.  Oracle allows you to use IPs from to  All installations included in the cluster must be listening on the same address (IP and port number).  The Oracle Universal Installer is the easiest way to setup multicasting.  Select the advanced installation at the opening screen and enter the IP and port in the Cluster Topology Configuration screen (example below).  Make sure that you select an open port and an IP address that will not conflict with any other application that may also be using multicast. 

Read below how you to get started with OracleAS multicast communications:


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