Application Server Role

Applies To: Windows Server 2008

Application Server is an expanded server role in the Windows Server® 2008 operating system. The new version of Application Server provides an integrated environment for deploying and running custom, server-based business applications. These applications respond to requests that arrive over the network from remote client computers or from other applications. Typically, applications that are deployed and run on Application Server take advantage of one or more of the following:

  • Internet Information Services (IIS) (the Hypertext Transfer Protocol (HTTP) server that is built into Windows Server)

  • Microsoft® .NET Framework versions 3.0 and 2.0. (If you have applications that are built with the .NET Framework 3.5, you can download and install the .NET Framework 3.5 onto the operating system.)


  • COM+

  • Message Queuing

  • Web services that are built with Windows Communication Foundation (WCF)

We recommend that you use the Application Server role when Windows Server 2008 runs applications that depend on role services or features that are part of the integrated Application Server role and that you select during the installation process. An example might be a specific configuration of Microsoft BizTalk® Server that uses a set of role services or features that are part of the Application Server environment.

Typically, the Application Server role is recommended when you are deploying a business application that was developed within your organization (or developed by an independent software vendor (ISV) for your organization) and when the developer has indicated that specific role services are required. For example, your organization may have an order-processing application that accesses customer records that are stored in a database. The application accesses the customer information through a set of WCF Web services. In this case, you can configure one Windows Server 2008 computer as an application server, and you can install the database on the same computer or on a different computer.

Not every server application benefits from the installation of the Application Server role. For example, the Application Server role is not necessary to support Microsoft Exchange Server or Microsoft SQL Server on Windows Server 2008.

To determine if the Application Server role is useful for running your organization's business applications, have your administrators work closely with the application's developers to understand the requirements of the application, for example, whether it uses the .NET Framework 3.0 or COM+ components.

If you have applications that are built with the .NET Framework 3.5, you can download and install the .NET Framework 3.5 onto the operating system.

What does Application Server do?

Application Server provides the following:

  • A runtime that supports effective deployment and management of high-performance server-based business applications. These applications are able to service requests from remote client systems, including Web browsers connecting from the public Internet or from a corporate network or intranet, and remote computer systems that may send requests as messages.

  • The .NET Framework 3.0, which provides developers with a simplified programming model for connected server applications. Developers can use the built-in .NET Framework libraries for many application functions, including input/output (I/O), numerical and text processing, database access, XML processing, transaction control, workflow, and Web services. For system administrators, the .NET Framework provides a secure and high-performance execution runtime for server-based applications, as well as a simplified application configuration and deployment environment.

  • Windows Server 2008 installation by means of a new, user-friendly Add Roles Wizard that helps you choose the role services and features that are necessary to run your applications. The Add Roles Wizard automatically installs all features that are necessary for a given role service and makes it easier for you to set up and provision a computer as an application server for your business applications.

Who will be interested in this role?

This information about the Application Server role is primarily for information technology (IT) professionals who are responsible for deploying and maintaining an organization's line-of-business (LOB) applications. LOB applications are typically developed in your organization or for your organization.

An application server environment consists of one or more servers running Windows Server 2008 that are configured with the Application Server role. This includes servers that do the following:

  • Host applications that are built with the .NET Framework 3.0

  • Host applications that are built to use COM+, Message Queuing, Web services, and distributed transactions

  • Connect to an intranet or to the Internet to exchange information

  • Host applications that expose or consume Web services

  • Host applications that expose Web pages

  • Interoperate with other remote systems running on disparate platforms and operating systems

An extended Application Server environment can also include the following:

  • Domain-joined client computers and their users

  • Computers that are used primarily for management of the application servers

  • Infrastructure servers that run resources, such as Active Directory Domain Services (AD DS) or other Lightweight Directory Access Protocol (LDAP) repositories, Certificate Services, security gateways, process servers, integration servers, application or data gateways, or databases

What new functionality does this role provide?

The new, expanded version of the Application Server role is installed through the Add Roles Wizard in Server Manager. Administrators who have LOB applications that are built with the .NET Framework 3.0 may discover that setting up a hosting environment for these applications is simpler with this server role. The Add Roles Wizard guides the administrator through the process of selecting the role services or supporting features that are available in this role and may be necessary to run specific LOB applications.

Application Server Foundation

Application Server Foundation is the group of technologies that are installed by default when you install the Application Server role. Essentially, Application Server Foundation is the .NET Framework 3.0. (If you have applications that are built with the .NET Framework 3.5, you can download and install the .NET Framework 3.5 onto the operating system.)

Windows Server 2008 includes the .NET Framework 2.0, regardless of any server role that is installed. The .NET Framework 2.0 contains the Common Language Runtime (CLR), which provides a code-execution environment that promotes safe execution of code, simplified code deployment, and support for interoperability of multiple languages, as well as extensive libraries for building applications.

Application Server Foundation adds the .NET Framework 3.0 features to the baseline .NET Framework 2.0 features. For more information about the .NET Framework 3.0, see .NET Framework Developer Center (

If you have applications that are built with the .NET Framework 3.5, you can download and install the .NET Framework 3.5 onto the operating system.

Why is this functionality important?

The key components of Application Server Foundation are installed as a set of code libraries and .NET assemblies. The following are the key components of Application Server Foundation:

  • Windows Communication Foundation (WCF)

  • Windows Workflow Foundation (WF)

  • Windows Presentation Foundation (WPF)

Of these three, WCF and WF are commonly used in server-based applications as well as client-based applications. WPF is used primarily in client-based applications, and it is not discussed further here. For more information about WPF, see Windows Presentation Foundation (

WCF is the Microsoft unified programming model for building connected applications that use Web services to communicate with each other. These applications are also known as service-oriented applications (SOA), and they are becoming increasingly more important for business. Developers can use WCF to build SOA applications that employ secure, reliable, transacted Web services that communicate across platforms and interoperate with existing systems and applications in your organization.

WCF enables developers to compose or combine the various technologies that are available today for building distributed applications (COM+ and .NET Enterprise services, Message Queuing, .NET Remoting, ASP.NET Web Services, and Web Services Enhancements (WSE)) in ways that make sense for your organization’s business needs and computing environment. For more information about WCF, see What is Windows Communication Foundation? (

WF is the programming model and engine for building workflow-enabled applications quickly on Windows Server 2008. A workflow is a set of activities that describe a real-world process, such as an order-purchasing process. A workflow is commonly described and viewed graphically—something like a flowchart. The description of the workflow is often called "the model." Work items pass through the workflow model from start to finish.

Work items or activities within the model can be executed by people or by systems or computers. While it is possible to describe a workflow in traditional programming languages as a series of steps and conditions, for more complex workflows or workflows that support simpler revisions, designing the workflow graphically and storing that design as a model is typically much more appropriate and flexible.

WF supports system workflow and human workflow across a variety of scenarios, including the following:

  • Workflow in LOB applications

  • The sequential flow of screens, pages, and dialog boxes as presented to the user in response to the user's interaction with the user interface (UI)

  • Document-centric workflow, for example, the processing of a purchase order or a medical record

  • Human workflow interaction, such as sending e-mail to a business client and receiving e-mail from the client

  • Composite workflow for SOA

  • Business-rule-driven workflow, for example: "On a Monday at 17:00, send an update catalogue request to business partners."

  • Workflow for systems management

For more information about WF, see Windows Workflow Foundation (

What works differently?

Although there is an Application Server role in Windows Server 2003, the new, expanded Application Server role that is available in Windows Server 2008 is not simply an upgrade from the application server configuration tool that is included in Windows Server 2003 or an earlier operating system. Because the role functionality is completely new, administrators should be aware that there is no migration path for the Application Server configuration tool from Windows Server 2003 or earlier operating systems.

How do I resolve these issues?

If you upgrade your server to Windows Server 2008 from Windows Server 2003 or an earlier operating system, and you want to use the capabilities of the Application Server role, you must reinstall the Application Server role by using the Add Roles Wizard in Server Manager. As long as you configure Windows Server 2008 with the correct application services by using the Add Roles Wizard in Server Manager, you can easily move your applications from Windows Server 2003 to Windows Server 2008.

When should I use the Application Server role?

If the server-based LOB applications that you need to deploy and manage require one or more of the following technologies: Microsoft .NET Framework 3.0, Message Queuing, COM+, or distributed transactions, consider configuring your server in the Application Server role.

If you have applications that are built with the .NET Framework 3.5, you can download and install the .NET Framework 3.5 onto the operating system.

How should I prepare for installation?

As a part of your preparation for installing the Application Server role, create an inventory of the applications that you will run on this server. If you are an administrator, work with your developers or the ISV who developed the applications to identify the supporting technologies and configurations that must be present on the server to run the applications. Then, map these technologies to the role services that are described in the following sections so that you can select and properly configure the services during server role installation. Typically the developer or ISV provides a list of the technologies that are required to be installed for this application, for example, the .NET Framework 3.0.

Web Server

This option installs IIS version 7.0, the Web server that is built into Windows Server 2008. IIS has been available in Windows Server for many years, but has been revised significantly for Windows Server 2008 to provide improvements in performance, security, management, supportability, reliability, and modularity.

IIS provides the following baseline benefits:

  • IIS makes it possible for Application Server to host internal or external Web sites or services with static or dynamic content.

  • IIS provides support for running ASP.NET applications that are accessed from a Web browser.

  • IIS provides support for running Web services that are built with Microsoft WCF or ASP.NET.

COM+ Network Access

This option adds COM+ Network Access for remote invocation of applications that are built on and hosted in COM+ and Enterprise Services components. Such applications are also sometimes called Enterprise Services components.

COM+ Network Access is one of the remote invocation capabilities that has been supported in Windows Server since Windows 2000 Server, and it continues to be supported in Windows Server 2008. Newer applications typically use WCF to support remote invocation because WCF provides interoperability across multiple platforms.

Windows Process Activation Service

This option adds Windows Process Activation Service (WAS). WAS can start and stop applications dynamically, based on messages that are received over the network through HTTP, Message Queuing, TCP, and named pipes protocols. Dynamic start and stop of applications means that server resources are used more efficiently. WAS is a new service in Windows Server 2008.

Net.TCP Port Sharing

This option adds the Net.TCP Port Sharing Service. This role service makes it possible for multiple applications to use a single TCP port for incoming communications. For example, an SOA that is built with WCF can share the same port. Sharing ports is often a requirement when firewall configurations or network restrictions allow only a limited number of open ports or when multiple distinct instances of a WCF application must be running and available at the same time.

So that multiple WCF applications can share ports (multiplexing), the Net.TCP Port Sharing Service performs the multiplexing. The Net.TCP Port Sharing Service accepts incoming connection requests using the TCP protocol. The service then automatically forwards incoming requests to the various WCF services based on the target addresses of the requests. Port sharing works only when the WCF applications use the net.tcp protocol for incoming communications. Net.TCP Port Sharing is a new service in Windows Server 2008.

Distributed Transactions

Applications that connect to and perform updates on multiple databases or other transactional resources may require that these updates are performed with "all-or-none" transactional semantics—a technology that ensures that every part of the transaction is complete or that the whole transaction is rolled back to its original state.

Support for distributed transactions in Windows Server 2008 provides a way for applications to have this requirement met. Distributed transaction support has been in Windows Server since Microsoft Windows NT® Server 4.0, and this support continues in Windows Server 2008.

Is this role available in all editions of Windows Server 2008?

Application Server is available in the following editions of Windows Server 2008:

  • Windows Server 2008 Standard

  • Windows Server 2008 Enterprise

  • Windows Server 2008 Datacenter

  • Windows Server 2008 for Itanium-Based Systems

The Application Server role is not available in the following edition of Windows Server 2008:

  • Windows Web Server 2008

Does it behave differently in some editions?

Application Server behavior does not vary based on the edition of Windows Server 2008.

Is it available in both 32-bit and 64-bit versions?

Application Server is available in both 32-bit and 64-bit versions of Windows Server 2008.