ISO/IEC 23001-2:2008 specifies the Fragment Request Unit technology. It comprises a syntax and semantics for expressing a request for fragments of XML. It also specifies how such requests can be used in XML based systems such as ISO/IEC 15938-1 and ISO/IEC 23001-1. The technology can be used in resource constrained environments so that only the fragments of XML of interest at a given time need be transmitted to a requesting peer from a responding peer. It can also be used for node-by-node navigation of a remote XML document.