This figure shows two unclustered OC4J instances: the Web-tier is deployed to one and the EJB-tier is deployed to the other. In this figure, the remote EJB client running on the Web-tier OC4J instance is an EJB. When it accesses a remote EJB, it looks in the ejb-jar.xml file for the logical name and OC4J resolves this to the actual name and locates the JNDI properties necessary to access the EJB-tier OC4J instance by looking in the orion-ejb-jar.xml file ejb-ref-mapping element.