What is AppFabric?
AppFabric is a set of hosted services and acts as middleware between Azure 
applications. The definition from the Windows Azure website defines AppFabric as:
"Windows Azure AppFabric provides a comprehensive cloud middleware platform for 
developing, deploying and managing applications on the Windows Azure Platform. 
It delivers additional developer productivity adding in higher-level 
Platform-as-a-Service (PaaS) capabilities on top of the familiar Windows Azure 
application model. It also enables bridging your existing applications to the 
cloud through secure connectivity across network and geographic boundaries, and 
by providing a consistent development model for both Windows Azure and Windows 
Server"
The important services of AppFabric are:
- Service Bus
- Access Control
- Caching
- Integration
- Composite Application
![Windows-zure AppFabric]()
Service Bus Service
The Service Bus service provides the functionality for secured connectivity and 
messaging between disconnected applications.
Access Control Service
The Access Control service provides identity and access control to web 
applications and services. The support included for identity providers like 
Windows Live ID, Google, Yahoo, Facebook etc. 
The flexibilities provided by decoupling of authorization rules and the application. 
The authorization rules can be deployed in the Access Control. Thus our 
application will be clean and focusing on just the business needs.
Caching Service
The Caching service provides a distributed, in-memory, highly available caching 
services. The service provides advantages like no installation and instance 
management and scalability based on requirement.
Integration Service
The Integration service provides BizTalk Server integration capabilities, 
integration patterns to ease development. It also provides Business Activity 
Monitoring and Rules as well as trading partner portal and enabling business to 
business pipelines.
Composite Application Service
The Composite Application Service eases the deployment of applications that use different Windows Azure services. It contains .NET Framework extensions and 
Visual Studio integration components to support the features.
These services will be explored in the upcoming articles.
Software Development Kit (SDK) Download
You need to download the AppFabric SDK to start the learning. The download can 
be done using the url. 
![Windows-zure]()
The first two downloads are source code samples in C# and Visual Basic language. 
The last two downloads represent the SDK for 64 bit and 32 bit installations.
Download the SDK based on your processor architecture.
Installation
Now run the downloaded executable and you can see the dialog as below.
![AppFabric]()
Click the Next button to continue. 
![AppFabric in Windows-zure]()
In the appearing screen above click the Install button to do the installation.
Summary
In this article we have seen about AppFabric, various services inside it and the 
installation of AppFabric SDK.