WebSphere Application Server Architecture
WebSphere Application Server is a collection of networks. WebSphere architectures contain one or more computer systems, which are referred to in WebSphere terminology as nodes. Nodes exist within a WebSphere cell. A WebSphere cell can contain one node on which all software components are installed or multiple nodes on which the software components are distributed.
A typical WebSphere cell contains software components that may be installed on one node or distributed over multiple nodes for scalability and reliability purposes that include:
A Web server that provides HTTP services
A database server for storing application data
WebSphere Application Server (WAS) V5.
The architecture of WebSphere Application Server consists of these software components:
The WebSphere Application Server subsystem, QASE5, contains the jobs that pertain to WebSphere Application Server – Express. In addition to the jobs running in the QASE5 subsystem, your applications may also use jobs running in other subsystems.
The webSphere 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:
The Web container runs within the application server and handles requests for servlets, JavaServer Pages files, and the Web applications that contain them.
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 name server provides the implementation of the JNDI service. You can bind WebSphere Application Server resources to JNDI names, which allows applications to access resources such as data sources and mail providers.
The WebSphere Application Server 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.
The HTTP server receives requests for server-side components (such as servlets and Java Server Pages) and passes the requests to WebSphere Application Server through an interface called the WebSphere plug-in. WebSphere Application Server – Express supports these HTTP servers:
IBM HTTP Server for iSeries (powered by Apache)
Lotus Domino HTTP Server
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 ships two plug-ins; one for IBM HTTP Server for iSeries (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.