Mapping the specification IMS Learning Design and the Course Management System Moodle is a logical step forward on interoperability between eLearning systems and specifications in order to increase the best acceptance of the specifications into the widespread world of the eLearning systems and to ensure the standardization of the outputs from the systems to be used in others. IMS Learning Design and Moodle look for a common understanding focused on the integration of information packages modelled by each part in the other. The final goal aims at Moodle playing an IMS LD package. A second step will map a Moodle course to be used in any IMS LD complaint tool. The Unit of Learning in IMS LD and the course in Moodle become the perfect couple where to find several elements that should match each other. This paper shows how to make this understanding, mapping related elements in both to get a list of pairs easy to translate from one to another, and to define also a list of requirements for this protocol.