Dial-Gate Web Services are achieved with SOAP. SOAP (originally Simple Object Access Protocol) is a protocol for exchanging XML-based messages over a computer network, commonly using HTTP as a transport protocol. SOAP forms the foundation layer of the Web services stack, providing a basic messaging framework that more abstract layers can build on.

From the draft World Wide Web Consortium (W3C) specification: SOAP is a lightweight protocol for exchange of information in a decentralized, distributed environment. It is an XML based protocol that consists of three parts: an envelope that defines a framework for describing what is in a message and how to process it, a set of encoding rules for expressing instances of application-defined data types, and a convention for representing remote procedure calls and responses.

Web Services communicate using a concrete set of protocols based on a common architecture with SOAP as its foundation. There are several different types of messaging patterns in SOAP, but by far the most common is the Remote Procedure Call (RPC) pattern, in which one network node (the client) sends a request message to another node (the server), and the server immediately sends a response message to the client.

In order to add more flexibility to the integration of the Dial-Gate Application Server with existing client's application servers, a SOAP interface is provided to write SOAP clients in different programming languages, such as Java, .NET, Perl, etc. The SOAP interface offers only a limited number of implemented operations; more complex operations need to be performed using the Dial-Gate administrator Web interface.

To ensure secure transactions, SOAP communication is authenticated and encrypted between the SOAP client and Dial-Gate Server. Typically, any Dial-Gate administrator username/password credentials can be used by the SOAP client to be authenticated with the server. All SOAP traffic is encrypted by using SSL over HTTP (or HTTPS), so port 443 (default HTTPS port) must be open between the client and the server.

If the Dial-Gate Application Server is using a self-signed certificate, the SOAP client has to be configured to accept any certificate; otherwise the SOAP client can reject the server certificate.

One of the straightforward ways to write SOAP client, is to use the WSDL language and an automatic tool (like the .NET tool wsdl.exe or the axis java WSDL tool) that will generate a ready to use client code.

According to the W3C: Web Service Definition Language (WSDL) is an XML format for describing network services as a set of endpoints operating on messages containing either document-oriented or procedure-oriented information. The operations and messages are described abstractly, and then bound to a concrete network protocol and message format to define an endpoint. Related concrete endpoints are combined into abstract endpoints (services).

WSDL is often used in combination with SOAP and XML Schema to provide Web Services over the Internet. A client program connecting to a Web Service can read the WSDL to determine what functions are available on the server. Any special data types used are embedded in the WSDL file in the form of XML Schema. The client can then use SOAP to actually call one of the functions listed in the WSDL.

The Dial-Gate Application Server publishes the Web service WSDL with the URL:
https://<your Gate server>/services/soap/GateService?WSDL
Authentication is required (you can use a Web interface administrator username/password). Once the client is authenticated, it can perform similar functions as the Dial-Gate Web Interface, for example, adding a Subscriber.