difference between unicast and multicast in weblogic

Multicast	Unicast
Only option in pre-10.0 versions of WLS, continues to exist in version 10+	Available from WLS 10.0 onwards
Uses UDP Multicast	Uses TCP/IP
Requires additional configurations to Routers, TTL when clustering across multiple subnets.	Requires no additional configuration to account for network topology.
Requires configuring the Multicast Listen Address and Port.  May need to specify the Network Interface to use on machines with multiple NICs.	Simply specify the listen address.  Supports using the Default Channel or a Custom Network Channel for cluster communication.
Each message delivered directly to and received directly from the network	Each message delivered to a group leader, which retransmits the message to other group members (N – 1) and any other group leaders (M – 1), if they exist.  The other group leaders then retransmit the message to their group members resulting in up to NxM network messages for every cluster message. Message delivery to each cluster member takes between 1 and 3 network hops.
Every server sees every other server	Group leaders act as a message relay point to retransmit messages to its group members and other group leaders.
Cluster membership changes require 3 consecutive missed heartbeat messages to remove a member from the cluster list.	Cluster membership changes require only a single missed heartbeat message to remove a member from the cluster.