XML_RPC is a standard for distributed processing over the internet. RPC: remote procedure call is a
mechanism to launch procedures that may exist in different machines and be programmed in different
languages. This is the key paradigm of distributed processing. In a distributed processing environment
we can, for example, find a calculator software that runs the adding and substracting operations in
different machines, the adding operation might be programmed in APL in a RS6000 machine and the
substraction in "C" in a Unix Host. Other developers building distributed calculators can also use
this "distributed" procedures or choose better ones. In RPC the key components are "procedures", servers
provide procedures that the clients can call. Procedures might receive paremeters and return values.
XML_RPC implements the RPC mechanism by using an XML vocabulary for passing and receiving data and the
HTTP as the protocol carrier. XML_RPC servers accept XML_RPC requests and return XML_RPC responses.
XML_RPC clients send XML_RPC requests and accept XML_RPC responses. They must decode the response and
provide the answer in the way they want.