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 a JSP/Servlet. When the JSP/Servlet services a browser request, it accesses a remote EJB, it looks in the web.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-web.xml file ejb-ref-mapping element.