From 1997 until 2003 he was employed at KPN Research. Since 2003 he is employed at TNO, where he deals with quality aspects of ICT networks. In 2011 he became Principal Scientist, responsible for the research program on ICT Infrastructures. Since 2005 Robert is part-time affiliated with the Delft University of Technology, at the faculty of Electrical Engineering, Mathematics and Computer Science. Since 2010 he is a part-time full professor with the chair ""Robustness of Complex Networks".