Overview of WebSphere Application Server - Express architecture

This image shows the high-level architectural components of WebSphere Application Server - Express for iSeries.

The architecture of WebSphere Application Server - Express consists of these software components:

• WebSphere subsystem
  The WebSphere Application Server - Express subsystem, QASE51, contains the jobs that pertain to WebSphere Application Server - Express. In addition to the jobs running in the QASE51 subsystem, your applications may also use jobs running in other subsystems.

• Application server
  The application server provides the runtime environment for server-side Java components (such as servlets and JavaServer Pages). An application server contains the following architectural components:

  • Web container
    The Web container runs within the application server and handles requests for servlets, JavaServer Pages files, and the Web applications that contain them.

  • Name server
    The Java Naming and Directory Interface, or JNDI, is used to provide access to Java components within a distributed computing environment. The WebSphere Application Server - Express name server provides the implementation of the JNDI service. You can bind WebSphere Application Server - Express resources to JNDI names, which allows applications to access resources such as data sources and mail providers.

  • Security server
    The WebSphere Application Server - Express security server provides security infrastructure and mechanisms to protect sensitive application resources and administrative resources and to address enterprise end-to-end security requirements on authentication, on resource access control, on data integrity, confidentiality, and privacy, and on secure interoperability.

• HTTP server
  The HTTP server receives requests for server-side components (such as servlets and JavaServer Pages) and passes the requests to WebSphere Application Server - Express through an interface called the WebSphere plug-in. WebSphere Application Server - Express supports these HTTP servers:

  • IBM HTTP Server for i5/OS (powered by Apache)
  • Lotus Domino HTTP Server

• WebSphere plug-in
  WebSphere Web server plug-ins enable the Web server to communicate requests for dynamic content, such as servlets, to the application server. WebSphere Application Server - Express ships two plug-ins; one for IBM HTTP Server for i5/OS (powered by Apache) and one for Lotus Domino HTTP Server. The plug-ins use a configuration file to determine whether a request should be handled by the Web server or the application server. For example, the plug-in forwards servlet requests to the application server. If you are using the HTTP server to serve HTML files, then the plug-in forwards HTML requests to the HTTP server.