As of the Red Hat Enterprise Linux 6.2 release, the nodes in a cluster can communicate with each other using the UDP Unicast transport mechanism. It is recommended, however, that you use IP multicasting for the cluster network. UDP unicast is an alternative that can be used when IP multicasting is not available.
You can configure the Red Hat High-Availability Add-On to use UDP unicast by setting the
parameter in the
configuration file. You can also specify Unicast from the page of the Conga
user interface, as described in Section 4.5.3, “Network Configuration”