This figure shows an example of an high availability architecture where an Oracle9iAS instance can contain one Oracle HTTP Server instance and zero or more OC4J processes. Here, Oracle9iAS Web Cache is used as a load balancer to route requests. OPMN within the Oracle9iAS instance environment monitors the Oracle HTTP Server and OC4J processes. If either Oracle HTTP Server or OC4J fail, OPMN restarts the failed process. This enables a maximum level of availability of the components within an Oracle9iAS instance.