There is a long history of this topic and I have been telling myself that I will write a BLOG on this topic so that I can save time in the reply every time this topic comes up. I promise to keep this short and please feel free to challenge any of my points as I live for customer feedback 😉 so here goes…
I will start by saying that all of the XSD schemas and B2MML structures are fully supported within the MII environment and any structure that you can conceive in B2MML (standard or custom) is possible to generate and manage inside of MII. My question to you, and one you will have to ask yourself, is why do you want to use B2MML in the first place? The reason why I ask this question is based on a couple of facts about the B2MML standard:
- If you have a standard SAP ERP structure, like an IDOC or RFC, in XML format (which is how they appear natively in MII) then why map to another XML structure, B2MML, only to have the MES layer convert that XML to a native format so that it can be consumed? Why not go directly from the IDoc/RFC/BAPI to the native MES interfaces…MII allows you to achieve this mapping in the graphical environment of the SAP MII logic engine.
- B2MML offers a standard way to interface to an MES…however, most cases require customizations to the XML to accommodate the “real-world” which means that customization has to be done twice. Once in the SAP IDoc/RFC/BAPI to B2MML Translation and again in the B2MML to MES translation and I have seen this get messy. This is why, for our own discrete MES solution, we did not go with the B2MML approach but rather with the IDoc/RFC/BAPI to native MES approach.
We (SAP) did deliver some templates around this to the SDN some time ago, but our customers quickly realized the points that I raised above as obstacles that proved to be counterproductive to their project. In short our experiences with B2MML is that it looks nice on paper, but it does not implement well in the real-world. Plus we offer templates to interface to SAP ERP out of the box on the SDN and since all of these interfaces are exposed as XML it’s very easy to manage the integration between MII & ERP, the only real concern from here if you decide to take the B2MML route:
- How heterogenous are your MES implementations?
- If very, then would B2MML in standard form be enough or would you have to customize it anyway and in this case the standard ERP IDoc and BAPI/RFC XML structures will probably suffice as your integration standard.
- If some variation, then MII content can get you the rest of the way without double managing customizations and allowing you to leverage your core ERP implementation directly
- Why are you pushing for B2MML, does your MES vendor recommend a flat file type integration with their MES or do they offer technical interfaces like web services?
- What does B2MML get you that the SAP ERP standard IDocs/RFC/BAPIs do not already provide? Please note that B2MML was designed without a product like MII in mind that service enabled and provided a local XML view of your SAP ERP environment via native integration.
Hope this helps and I welcome your comments and feedback on this topic,