This paper presents the Dyn-MatPlanWDM tool, an educational network planning tool for wavelength-routing WDM networks. The tool considers the on-line or dynamic network operation. Traffic is composed of higher level traffic connections. The planning algorithms dynamically decide on the virtual topology design and the routing of the flows on top of it. The input parameters to the planning problem are the network physical topology, technological constraints like the number of transmitters, receivers, optical converters, the generator module and the planning module to test. The tool is implemented as a MATLAB toolbox. The set of generators and planning modules included can be easily extended. In particular, a set of libraries are provided to ease the composition of new heuristic algorithms. A Graphical User Interface is supplied which aids the user to test and trace the network evolution. The GUI is designed to support an educational use of the tool.