WebLogic can also use Multicast for cluster communications.
When configured for using Multicast, the Managed Servers of the cluster subscribe to a Multicast address and port and listen for heartbeats and cluster messages. Unlike Unicast, Multicast communication uses UDP and broadcasts the message through the network and therefore does not guarantee that the message is received.
To configure Multicast, the Administration Server must be running.
To configure the Multicast communication for the cluster: