Tuesday, April 19, 2005

EDI - Simple enough?

A comment by Mark Baker around EDI got me thinking about the current amount of infrastructure we are building on top of the transport. Today millions of business messages are flowing formatted as EDI messages and thousands of business processes are built using the MEP defined by EDI documents.

So what is wrong with just using EDI. Probably a couple of things, at one point the cost of the initial transport hardware and communications infrastructure but this has been solved by the draft AS2 standard which is essentially EDI over http(s) which has reduced the costs dramatically. So much so Walmart has mandated it for all communications.

The amount of work that has gone into the MEP and the definition of the document elements is huge and extremely valuable IP. The only remaining piece is the actual format itself which is very “concise” as it was designed when bandwidth was expensive. The format itself is hard to work with compared with XML due mainly to the lack of tools. If every language had an open source EDI parser (or two) and a transformation tool like XSLT would everyone be using EDI today?

The mechanics of EDI at the MEP level provide a fairly complete set of business interactions but getting into the details of the message and extending the messages is very complex and requires very specific knowledge that is only applicable to EDI - no one has every used EDI as a format for config files or build scripts. XML on the other hand has become the universal data language, because it is so easy to manipulate and mold.

In some ways the discipline that EDI imposed has resulted in a loss of simplicity as instead of a set of well defined MEPs we now have a large number of standards that try and do the same but in fact do not focus on the MEP but rather on making the communication more complex. Where is the WS-850 rather than the generic WS-Metadata. Are we missing the point because it is to easy to avoid it?


Anonymous said...

EDI is anything but simple - and I don't believe this is just a question of whether or not you use it on a VAN or on the Internet. The fact that XML is both self-describing and (often) human-readable is a large difference - an EDI message can only be understood if both parties have agreed what, exactly, they want to communicate.

John McDowall said...


I totally agree with you - I failed to make my point. I was trying to illustrate that the success of EDI (in spite of its complexity of message format) was due to it well designed MEP. Now we have XML for message formats which is so much easier and widely understood and adopted. Rather than create more complex protocols should we not be developing a set of standard MEP such as 850 et al. Sometimes adding easy of use and simplicity distracts us from the real problem.

So yes you are right EDI as a format is very complex and ugly. XML is the way to go - but I am perhaps questioning the particular direction we have taken.