The different ways in which concepts within computer networks are understood by master level students who take an internationally distributed project-based course have been identified in an empirical, qualitative, phenomenographic research project. Students, working in teams of six, three in each of the participating countries, collaborate to produce a software system to control a modified version of a toy. The students’ learning of a computer networking protocol is presented in this paper, as well as a discussion on the generalisability to other groups and other situations. Teaching, based on this kind of results has been showed to render a considerably better learning outcome. The results are also useful when studied in the light of the students’ learning environment, since relations between the learning outcome and the learning environment can be discerned. This offers insights to be used in the design of distributed courses.