More new Web Service work is making its way through the standards process, and this time it’s MTOM at W3C. MTOM (Message Transmission Optimization Mechanism) is a spec for attaching large binary data to a SOAP message, while still retaining the SOAP processing model (by mapping the attachments into the XML Infoset of the message).  Achieving W3C CR status is an important milestone in the lifetime of this spec.


MTOM is very strategic because it enables composition of attachments with WS-Security.  The original spec in this space, called SOAP with Attachments (SwA) is what ebXML Messaging has been using for the last 3 years. 


I’m not sure that end customers understand that there is a critical 'gotcha' with using SwA - namely that you can't use WS-Security and SwA together to secure attachments in addition to the SOAP header/body.  It seems unfair for customers to have to make a choice between security and attachments.


The W3C references for MTOM are here


and if you are interested in some more history on the MTOM pedigree then have a look at Omri Gazitt’s blog. I think the operative phrase, as Omri mentions, on getting to MTOM is "... our understanding of the requirements for Web Services attachments has evolved over time" which comes back to my earlier blog about how web services is breaking new ground as a process on how real world standards can be done in record time (for something of this global scale).


More good stuff to come from web service pipeline, in due time.

Stay tuned.