I just wanted to write a quick note about a comment by Don O’Brien at Steve Vinoski’s blog

“Dr. Ian Gorton (

mentioned MEST and SSDL in a workshop at the 2005 ICSE conference. Steve what are your thoughts on the intersection of the SSDL and MEST work with respect to WSDL 2.0 ?

The SSDL covers some very interesting concepts (MEP Message Exhange Patterns) which I’ve seen in some the new WSDL work.”

Please note that MEST is an architectural style while SSDL is just a piece of technology that can be used to build applications which follow the MEST principles (most importantly message-orientation, state on the wire, etc.).

The reason the MEP SSDL Protocol Framework looks familiar to those looking at the WSDL 2.0 is because it was designed to be a direct replacement. We wanted to demonstrate that we can capture exactly the same MEPs as WSDL 2.0 without needing the ‘service’ and ‘operation’ abstractions and also illustrate that through having richer protocol frameworks (Rules, CSP, SC) we can do so much more.