When you install Microsoft Dynamics NAV Server on a computer, you automatically install the Microsoft Dynamics NAV Business Web Services service, which is a Windows service.
Use this service to establish communication between external processes and applications and Microsoft Dynamics NAV 2009. Web service integration with Microsoft Dynamics NAV is supported through Web service–enabled pages and codeunits. With proper authentication and authorization, external systems can read and write data on pages and call codeunits as defined by the common Web service protocols. When pages and codeunits are published as Web services from Microsoft Dynamics NAV, they are immediately available for Web service requests over the network.
Different Types of Web Services
Microsoft Dynamics NAV supports exposing either pages or codeunits as Web services. You can also use extension codeunits to extend the default set of methods that are available on a page. This enables you to perform operations other than standard page operations.