To transfer data between computers and systems in the language of "XML"
it is necessary to use a common protocol or format for data exchange.
For this purpose, SOAP or "Simple Object Access Protocol" was developed

The data in this protocol is also writen in the "XML".
Each message contains a control header "Header"
and the data element "Body".

An important feature of the protocol "SOAP" is that the "XML" can be transferred analogously
as usual the website in the "HTML" using the same technologies like "TCP/IP" and "HTTP".
So, you do not need an additional network infrastructure and hardware.