7. Orchestration and Extension : 7.3 vCloud Messages : 7.3.3 Extension
   
7.3.3 Extension
An extension is a script or an application that has the following capabilities:
*Subscribes to an AMQP queue for receiving new messages.
*Triages the received messages.
*Processes messages into operations (internal or external calls).
*Calls the vCloud API to get more information on the objects involved in an operation and takes action on blocked tasks.