46 IBM WebSphere Application Server V8 Concepts, Planning, and Design Guide
3.1 Core concepts of WebSphere Application Server
The following concepts are at the core to understanding the architecture of WebSphere
Application Server V8:
򐂰 Applications
򐂰 Application servers
򐂰 Profiles
򐂰 Nodes, node agents, and node groups
򐂰 Cells
򐂰 Deployment manager
A person in an administrative role must manage these concepts on a regular basis.
Understanding these concepts and how they apply to your environment will help facilitate any
design and troubleshooting situations.
This section provides information about these concepts. You can find additional concepts
about WebSphere Application Server that build on these core concepts in 3.2, “Additional
concepts for WebSphere Application Server” on page 57.
3.1.1 Applications
At the heart of WebSphere Application Server is the ability to run applications. WebSphere
Application Server V8 can run the following types of applications:
򐂰 Java EE applications
򐂰 Portlet applications
򐂰 Session Initiation Protocol applications
򐂰 Business-level applications
򐂰 OSGi applications
This section highlights these types of applications.
Java EE applications
The Java Platform, Enterprise Edition (Java EE), specification is the standard for developing,
deploying, and running enterprise applications. WebSphere Application Server V8 provides
full support for the Java EE 6 specification. The Java EE programming model has multiple
types of application components:
򐂰 Enterprise beans
򐂰 Servlets and JavaServer Pages (JSP) files
򐂰 Application clients
The primary development tool for WebSphere Application Server Java EE 6 applications is
Rational Application Developer for WebSphere V8. Rational Application Developer V8 or
Rational Software Architect V8 ships with WebSphere Application Server and contains the
tools that you need to create, test, and deploy Java EE 6 applications. Java EE applications
are packaged as enterprise archive (EAR) files.
Portlet applications
The Portlet container in WebSphere Application Server V8 provides the runtime environment
for Java Specification Requests (JSR) 268-compliant portlets. Portlet applications are
intended to be combined with other portlets collectively to create a single page of output. The
primary development tool for portlets on WebSphere Application Server portlet applications is
Rational Application Developer V8.
Chapter 3. Concepts of WebSphere Application Server 47
Portlets are packaged in web archive (WAR) files. The portlet run time does not provide the
advanced capabilities of WebSphere Portal, such as portlet aggregation and page layout,
personalization and member services, or collaboration features.
For more information about JSR 286, see the JSR page on the Java Community Process
website at:
http://jcp.org/en/jsr/detail?id=286
Session Initiation Protocol applications
Session Initiation Protocol (SIP) applications are Java programs that use at least one SIP
servlet written to the JSR 116 specification. SIP is used to establish, modify, and terminate
multimedia IP sessions. SIP negotiates the medium, the transport, and the encoding for the
call. After the SIP call has been established, the communication takes place over the
specified transport mechanism, independent of SIP. Examples of application types that use
SIP include voice over IP (VOIP), click-to-call, and instant messaging.
Rational Application Developer V8 provides special tools for developing SIP applications. SIP
applications are packaged as SIP archive (SAR) files and are deployed to the application
server by using the standard WebSphere Application Server administrative tools. SAR files
can also be bundled in a Java EE application archive (EAR file), similar to other Java EE
components.
For more information about SIP applications, see the following references on the web:
򐂰 JSR 116 SIP Servlet API 1.0 Specification
http://www.jcp.org/aboutJava/communityprocess/final/jsr116/
򐂰 JSR 116
http://jcp.org/en/jsr/detail?id=116
򐂰 RFC 3261
http://www.ietf.org/rfc/rfc3261.txt
Business-level applications
A business-level application is an administrative concept that expands the options that are
offered by the Java EE definition of an application. Enterprise-level applications have a
grouping notion. It includes WebSphere artifacts and artifacts that are not based on
WebSphere, such as Service Component Architecture (SCA) packages, libraries, and proxy
filters under a single application definition. Every artifact in the group is a composition unit.
A business-level application can be useful when an application has the following characteristics:
򐂰 Is composed of multiple packages
򐂰 Applies to the post-deployment side of the application life cycle
򐂰 Contains additional libraries or artifacts that are not based on Java EE
򐂰 Includes artifacts that run on heterogeneous environments that include WebSphere run
times and run times that are not WebSphere based
򐂰 Is defined in a recursive manner (for example, if an application includes other applications)
OSGi applications
The concept of OSGi evolved from managing software components that are deployed to
network devices such as storage area network (SAN) arrays. When a storage module is
removed from a system, the entire system does not fail. The system itself distributes
responsibility to other modules. With this concept, software components on network devices

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