RPC protocol

The remoting functionalities of RTAI-XML are implemented through an XML-RPC server waiting for incoming calls on a specific network port.

XML-RPC resources

As stated in the official web site, XML-RPC is a spec and a set of implementations that allow software running on disparate operating systems, running in different environments to make procedure calls over the Internet. It's remote procedure calling using HTTP as the transport and XML as the encoding. XML-RPC is designed to be as simple as possible, while allowing complex data structures to be transmitted, processed and returned.
There is a large number of XML-RPC implementations, for different programming languages and platforms. The RTAI-XML server is programmed in C++ using the open-source XmlRpc++ XML-RPC implementation.