Services in Ax

AX 2012 supports the following three kinds of services:

• Document services are query-based services that can be used to exchange data with external systems by sending and receiving XML documents. These documents represent business entities, such as customers, vendors, or sales orders.
• Custom services can be used by developers to expose any X++ logic, such as X++ classes and their members, through a service interface.
• System services are provided by Microsoft Dynamics AX. System services include the Query service, the Metadata service, and the User Session service.

Application Object Server (AOS) is the Windows Communication Foundation (WCF) service host for Microsoft Dynamics AX 2012 services that are exposed to users and applications on an intranet.

• To consume services over the Internet, you must host services on Internet Information Services (IIS).
• Services that are hosted on IIS use the WCF message routing service. IIS routes all service requests to AOS.
• All service requests are processed on AOS, regardless of whether they originate on the Internet or an intranet. AOS then returns a response to the service consumer via IIS.
• Exchanges that are configured to use Web services are processed synchronously and therefore are not queued.
• AX deploys the service that is based on Web Services Description Language (WSDL) to a subfolder of the virtual directory that is associated with the Web site that you provide.