Heartbeat Msg communication

•  WebLogic Server instances in a cluster communicate with one another using two basic network technologies:
• IP sockets, which are the conduits for peer-to-peer communication between clustered server instances.
• IP unicast or multicast, which server instances use to broadcast availability of services and heartbeats that indicate continued availability.
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• Multicast : Each server communicates with every member server in the cluster. Which means heartbeats are sent to every server. A multicast address and multicast port is used for listening to the messages.
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• Unicast : For the member servers in the cluster, group leaders are chosen and only those group leaders communicate with the servers among the group and these leaders notify each other about the availability of all the other servers.A network channel is used for communication between the servers. If no channel is specified, default network channel is used.
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• Each server communicates with every member server in a cluster that means heart beat messages sent to every server.
• For multicast u can see heart messages internally cmd is java utiles.MulticastTest -n -a -p (i.e multicast name,adress,port num)
• unicast means servers are in a cluster, group leaders are chosen those group leaders will comm the servers among the group