This paper presents the AulaNet learning management system, its architecture and the collaboration model that guided its development and that was refined during this process. A case study of an online course indicates the necessity to have an architectural support for collaboration aspects and a collaboration-based engineering approach to groupware development. This approach, Groupware Engineering, is based on Software Engineering and on concepts originated in the field of CSCW. Keywords Collaboration model, groupware engineering, groupware architecture, component framework.