The enterprise and the control systems exchange information that can be divided into four categories: product definition, production capability, production schedule, and production performance. Each of the categories includes data describing resources, that is, personnel, material, equipment, and process segments.
To exchange information, the Business-To-Manufacturing Markup Language (B2MML) is used. Messages are transferred as a set of XML files. The following diagram illustrates the data exchange between Level 4 (an ERP system) and Level 3 (MES):