JGroups is a messaging toolkit which allows developers to create reliable messaging applications where system reliability is an issue. JGroups can be used to create clusters whose nodes can send messages to each other.
The JGroups subsystem provides all the communication mechanisms for how the servers in a cluster talk to each other. EAP is preconfigured with two JGroups stacks.
udp - the nodes in the cluster use UDP (User Datagram Protocol) multicasting to communicate with each other. UDP is generally faster but less reliable than TCP.
tcp - the nodes in the cluster use TCP (Transmission Control Protocol) to communicate with each other. TCP tends to be slower than UDP, but will more reliably deliver data to its destination.
The preconfigured stacks can be used, or you can define your own to suit your system's specific requirements.