Just when the world is starting to figure out the nuances and applications of WSDL (Web Services Description Language), a new way of describing Web services messages has been thrown into the mix. A new "experimentalframework" for Web Services description -- called the SOAP Service Description Language (SSDL) -- has just been released. The purpose of the new language is to provide "an expressive, message-oriented language for describing interactions between Web Services."
But doesn't WSDL (Web Services Description Language) do the same thing already? Jim Webber, who was active in the creation in SSDL, explains in a recent post that SSDL "takes a different approach toWSDL by assuming that SOAP and WS-Addressing will underpin Web Servicesdevelopment and integration and is optimised and simplified for thosecases."
SSDL assumes, of course, that you're using SOAP as the messaging protocol, and that WS-Addressingis employed to embed addressing information within SOAPenvelopes and to bind those addresses onto underlying transportprotocols.
Jim Webber explains that the "major benefit of SSDL is notthat it is easy to read and write (or at least as easy as XML ever is),but that it is truly focussed on supporting SOAP messaging."