Thanks for the reply. That helps me to understand the difference between the two much better. We are working with our network engineering department to monitor the network traffic between the different machines based on various configurations (the app servers are located offsite in a data center). So far we have been focusing on different configurations at the JBossCache level, specifically the cache mode. If we start testing different JGroups configurations I'll post the results here. Just FYI, it's hard to determine the bottleneck since we only run into problems when running all 16 nodes. Fun stuff. ;-) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4061449#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...