Windows Azure AppFabric

Most people when they look at Windows Azure (WA), will assume that it is only suitable for new developments and would think that their existing systems will need to be completely re-written to leverage on the platform. That is an inaccurate thought but I can't blame them because most of the focus around WA were surrounding the Roles, the Storage and SQL Azure - painting a picture that it is a "new way of developing apps".

The truth is, WA does provide support for existing systems to slowly move to the cloud and provides a good platform for hybrid (cloud + on-premise) solutions. This is achieved through Windows Azure AppFabric - which in my opinion is given very little attention probably because it something that is not so easy to explain and doesn't have a local development environment.

The AppFabric comes with 2 very useful services today - Service Bus and Access Control. The third feature, Caching, is on the way with other features following suit later. If we have existing on-premise services that we would like to expose to partners, external systems, remote branches or mobile employees, we can leverage on the Service Bus. It provides a neat way to traverse through firewalls to create a relay between service consumers and service providers. The technology enabling this is simply a couple of Windows Communication Foundation (WCF) bindings.

The other component, the Access Control, allows us to secure our applications and endpoints with claims-aware federated security.

Therefore, if you want to expose some of your application's services to the external world without all the infrastructure investment, you can easily do it with Windows Azure AppFabric. (In fact, you can write some services on your PC at home and use AppFabric to connect to it wherever you go).

P.S. Take note that Service Bus charges by connections.