A tier is a logical grouping of services, potentially spread across more than one physical machine.
The client interface is provided through HTML for the HTML-based applications, and via a Java applet in a Web browser for the traditional Forms-based interface. In Oracle Applications Release 12, each user logs in to Oracle Applications through the E-Business Suite Home Page on a desktop client web browser. The E-Business Suite Home Page provides a single point of access to HTML-based applications, Forms-based applications, and Business Intelligence applications.
The application tier hosts the various services that process the business logic and manage communication between the desktop tier and the database tier. This tier runs the web server and the associated processes, concurrent processing server, Interaction and Oracle fulfillment server.
The database tier contains the Oracle database server which stores all the data maintained by Oracle Applications. This tier has the Oracle data server files and Oracle Applications database executables that physically store the tables, indexes, and other database objects in the system.
Oracle Process Manager and Notification Server (OPMN) is installed and configured on every tier designated to run the web application. OPMN provides an integrated way to manage all Oracle Application Server components. OPMN consists of two main pieces: the Process Manager and the Notification Server. The Process manager (PM) is the centralized process management mechanism in Oracle Application Server and is used to manage all Oracle Application Server processes. The PM starts, restarts, stops, and monitors every process it manages. It also performs death-detection and automatic restart of the processes. Oracle Notification Server (ONS) is the transport mechanism for failure, recovery, startup, and other related notifications between components in Oracle Application Server.
Oracle HTTP Server (OHS) is installed and configured on every tier that is designated to run the web application . It provides the key infrastructure required for serving the static and dynamic content generated by Oracle E Business Suite products.
Oracle Containers for J2EE (OC4J) is the core Java 2 Platform Enterprise Edition (J2EE) runtime component of Oracle Application Server. It is installed and configured on every tier that is designated to run the web application. It is a fully J2EE 1.5 compliant container that runs on a standard file based JDK 1.5 Java Virtual Machine and provides complete support for Java Server Pages (JSP) , Servlets, Enterprise Java Beans (EJB), Web Services and all J2EE services.
Web Entry Point
Web Entry Point refers to the host name which is designated to be used by all users to access the Oracle E-Business Suite Release 12 system. By default, the web entry point is set to the hostname of the application server where Oracle E-Business Suite is installed. In the case where a load-balancer is used, the Web Entry Point becomes the load-balancer’s host name.
Session Persistence is the act of keeping a specific user’s traffic going to the same server that was initially hit when the site was contacted for the first HTTP transaction. This is especially important for E-Business Suite as various modules bundled with the suite need to maintain session state. Session persistence is sometimes referred to as “server stickiness.”
Server Load Balancer
Load balancing can be defined as the technology and associated processes that distribute a website’s traffic among several machines in a cluster using a network-based device called a server load balancer. Cluster architectures allow all members of a group of machines to run the same web application, appearing to the outside world as a single machine.