Introduction

The Windows Azure AppFabric adds middleware services to the Windows Azure Platform. The initial focus extended Windows Communication Foundation (WCF) services into the cloud. However, the Windows Azure AppFabric now provides many higher-level services that simplify the use of the Windows Azure Platform. It provides a Service Bus that services can use to host public endpoints acting as rendezvous addresses for various capabilities. It provides a Caching service that Windows Azure hosted services can use to cache and share frequently used data. It provides an Access Control Service that exposes a cloud-based Secure Token Service (STS) that various services in the Windows Azure Platform use to facilitate claims-based authentication.

The Windows Azure AppFabric provides a labs environment where new features can be tried out as Community Technology Previews (CTP). Two very powerful features currently being previewed are Windows Azure AppFabric Queues and Topics, and Windows Azure...