Troubleshooting multicast

InfoSphere® MDM Collaboration Server uses ehcache to perform distributed caching of objects between Java™ virtual machines (JVMs), both on the same machine and in the same network. Each InfoSphere MDM Collaboration Server JVM needs to know about all of the other JVMs in the cluster. The way this is done is that a JVM will periodically send a multicast message, for example saying "I'm here!". If we did not use multicast, the configuration of all the caches would be very tedious and error-prone. Consequently, IBM recommends that you use the multicast configuration of ehcache. Although you can configure the cache setup in the $TOP/etc/default/mdm-ehcache-config.xml file yourself; note that IBM® does not support non-multicast configuration.