The pooled and rmi invokers are both legacy invokers and are not part of Remoting. The current default behavior for EJB2, EJB3, and JBossMessaging is to use an invoker based on Remoting. In particular:
* EJB2 uses UnifiedInvoker (see "jboss:service=invoker,type=unified" in $JBOSS_HOME/server/$CONFIG/conf/jboss-service.xml)
* EJB3 uses a variation of UnifiedInvoker (see "jboss.remoting:type=Connector,name=DefaultEjb3Connector,handler=ejb3" in $JBOSS_HOME/server/$CONFIG/deploy/ejb3.deployer/META-INF/jboss-service.xml)
Once you're using a Remoting based invoker, based on the Remoting socket transport, you can increase the number of worker threads on the server side, which would increase the number of clients that can connect to the server, with the "maxPoolSize" parameter. The default value, by the way, is 300.
For more information see Chapter 5 "Configuration" in the Remoting Guide:
* http://www.jboss.org/jbossremoting/docs/guide/2.2/html/index.html for Remoting version 2.2.2.SP10, and
* http://www.jboss.org/jbossremoting/docs/guide/2.5/html/index.html for version 2.5.0.SP2.