This diagram shows five zones:

• the external Internet, outside the DMZ firewall

• the Web Server Tier DMZ , between the DMZ firewall and the J2EE firewall

• the Infrastructure DMZ, inside the Web Server Tier DMZ, but separated from the other parts of DMZ by the Infrastructure Firewall

• the J2EE Business Logic DMZ, between the J2EE Firewall and the Intranet Firewall

• the corporate intranet, behind the intranet firewall.

The external Internet contains the external clients, which communicate across the DMZ Firewall with the Load Balancer.

The Web Server Tier DMZ contains the Load Balancer, which communicates with the OracleAS Single Sign-On and OC4J for Single Sign-on servers, as well as with Oracle Web Cache.

The Infrastructure DMZ contains Real Application Clusters, the OracleAS Metadata Repository, including product metadata, management metadata, and security metadata, and Oracle Internet Directory. Oracle Internet Directory communicates across the Infrastructure Firewall using SQL*Net. Oracle Internet Directory communicates with the Oracle HTTP Servers in the Web Server Tier DMZ.

The J2EE Business Logic DMZ contains J2EE without Web Cache. J2EE communicates using AJP with Oracle HTTP Server in the Web Server Tier DMZ.

The corporate intranet contains the customer database with business data, possibly in Real Application Clusters or a cold failover cluster. The customer database communicates using SQL*Net with the J2EE servers in the J2EE Business Logic DMZ.