See http://anonsvn.jboss.org/repos/jbossas/trunk/testsuite/src/main/org/jboss..., testisMasterReplica() for a test that simulates a network partition. That one configures the service being tested with a JGroups channel configured to use TUNNEL + an in-process GossipRouter. A simple call to GossipRouter.stop() is semi-equivalent to failing a network switch. Another possible approach is to use the JGroups DISCARD protocol. That's a test protocol that discards messages; discard them all and it's like a network partition. A test that uses that can be seen at http://javagroups.cvs.sourceforge.net/javagroups/JGroups/tests/junit/org/... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4142543#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...