what does XDR stand for? and what is it?

[Shaun]

im here looking and trying to figure out the xdrlib module, 
it says here - http://www.python.org/doc/current/lib/module-xdrlib.html
"The xdrlib module defines two classes, 
one for packing variables into XDR representation, 
and another for unpacking from XDR representation. 
There are also two exception classes."
my question is what is XDR? what does it stand for?
thanks
Shaun
=====================
Shaun Hogan
Interactive Enterprise Ltd.
alt. E-mail : shaun_hogan at yahoo.com
+353 86 8342529