For software design purposes, it's done via
Java Remote Method Invocation (RMI) and it's dangerous to look deeper, since you start becoming depending on server implementations.
TCP/IP the underlying protocol being used (at least on all the EJB systems I've worked with), but again, you shouldn't take advantage of that knowledge.
The one exception to that rule is that if you intend to access EJBs over a network, you want to make sure that the firewalls allow proper access.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.
