Windows Azure AppFabric Features, Queues, Topics and Subscriptions, which were in CTP for some time now have now been released. These enable new scenarios for Applications hosted on Windows Azure such as asynchronous Cloud Eventing, Event-Driven SOA, Load leveling/balancing and more.

A brief note on what the new features are -

Queues – Ability to create asynchronous messages which will be stored reliably till the consumer consumes them. If the consumer is offline for a while, the messages will get queued and can be accessed once the consumer comes online. Topics – Similar to Queues, but with a publish-subscribe mechanism such that each message on the topic can be subscribed to by multiple consumers (once they are registered to that topic). From the consumer’s point of view, each subscription looks like a virtual queue.

To know more about these new features you can go through the following resources on

Apart from this, AppFabric Service Bus also got new usage meters in addition to number of connections -

Entity Hours – counts the time from creation to deletion of an Entity (Queue, Topic, Subscription, Relay or Message Buffer) totaled across all Entities used during the period Message Operations – counts the number of messages sent to, or received from, the Service Bus, including requests that return empty.

These meters are only for information and for monitoring usage, but will not affect charges.

Windows Azure is a Cloud-PAAS offering from Microsoft for building scalable applications. Windows Azure AppFabric is a Middleware platform for Cloud Applications including service bus and access control services.