How exactly is SSDL better than WSDL?

Savas replied to my comments on SSDL. Thinking about my reaction, I thought about something else, though:

How exactly is SSDL better than WSDL?

SSDL is SOAP-only, but in WSDL you can easily just standardize with your partners on a single binding (because bindings in WSDL 2 can be reused across interfaces).

SSDL models headers, but I haven't seen yet an example of where a concrete header is better in a contract than a (possibly abstract) feature.

SSDL doesn't imply any semantics, expecting the functionality that a service (or an interaction) does to be defined by the specifications of the contracts - but SSDL is a specification of the contract, right? So the semantics would be in English in documentation within the SSDL file, right? Same with WSDL, except WSDL's interface (or operation) is the natural place where such documentation should be, whereas in SSDL it's (intentionally) not clear.

Instead of using SSDL, could we easily profile WSDL? Maybe such a profile would be of interest to the WS Description Working Group 8-)

Posted at 1712 on Tue, Feb 15, 2005 in category Work | TrackBack | Comments feed


The point about SSDL is that it assumes Web Services use SOAP as the unit of message transfer (delivered over arbitrary protocols). Therefore there is no perceived need (as there was in WSDL) to support a wealth of different bindings. Given how much of a commodity SOAP is, and how it has been so widely embraced I feel this is a very pragmatic approach.


Posted by: Jim Webber at February 18, 2005 5:13 AM