The Web Services Description Language (WSDL) (see Resources)
specification provides a simple XML-based vocabulary for
describing XML-based Web Services that are available over the
network. The services themselves communicate using the Simple
Object Access protocol (SOAP), HTTP, SMTP, or by some other
means; WSDL, however, gives the user the meta-data required to
set up the communications. WSDL itself says nothing about how to
publish or publicize such service descriptions, leaving this to
other specifications. Universal Description, Discovery and
Integration (UDDI), an initiative for creating directories of
Web Services, defines one framework for cataloging and
dispatching WSDL descriptions, but it is just emerging and is
quite complex. UDDI does some hefty lifting for online
contracts, and should certainly find its place soon in the
distributed services arena. However, since the first likely WSDL
deployments will be in tightly closed systems rather than over
the open Web, there is probably a better alternati