AppFabric is the middleware platform for developing, deploying and managing Azure application. AppFabric provides set of pre-built services to the Azure developer to increase the productivity. The set of services available are
Service Bus (Available): Service bus connects distributed Azure applications and also applications hosted in on-premise with Azure applications. Azure Connect is used for On-premise to Azure application connectivity. It uses various communication and messaging protocols like REST and HTTP.
Access Control (Available): It provides an easy way to identify the users in Azure web application. It can work with the federated AD authentication and also using web identities like live Id and Google.
Caching (April 2011): Caching service provides an application cache service for Windows Azure storage and SQL Azure. It caches any managed object with no object size limit and serialization cost.
Integration (Will release CTP on 2011): Integration provides common BizTalk server integration capabilities.
Composite App (Will release CTP on 2011): Composite applications are applications build out of pre-built components and third party components.