Clustering is a key element in building scalable Enterprise applications. The infrastructure used by JBoss AS for clustered applications is based on JGroups framework for the nodes inter-communication and JBoss Cache for keeping the cluster data synchronized across nodes.
JGroups can use both UDP and TCP as communication protocol. Unless you have network restriction, you should stay with the default UDP that uses multicast to send and receive messages.
You can tune the transmission protocol by setting an appropriate buffer size with the properties
ucast_send_buf_size. You should as well increase your O/S buffer size, which need to be adequate to accept JGroups' settings.
JBoss Cache provides the foundation for robust clustered services.
By configuring the cacheMode you can choose if your cluster messages will be synchronous (that is will wait for message acknowledgement) or asynchronous. Unless you need to handle cache...