When deploying Coherence on AIX please be aware of the following:
There is an issue with IBM's 1.4.2, and 1.5 JVMs for AIX which may prevent them from allocating socket buffers larger then 64K (Oracle recommends 2MB). This issue has been addressed in IBM's 1.4.2 SR7 SDK and 1.5 SR3 SDK.
AIX 5.2 and above default to running multicast over IPv6 rather then IPv4. If you are running in a mixed IPv6/IPv4 environment you will need to configure your JVMs to explicitly use IPv4. This can be done by setting the java.net.preferIPv4Stack system property to true on the Java command line. See the IBM 32-bit SDK for AIX User Guide for details.
On AIX it is suggested that each Coherence cluster use a unique multicast address and port, as some verions of AIX will not take both into account when delivering packets. See the multicast-listener for details on configuring the address.