INCE this thesis is not the fruit of a single person, I would like to express my sincere gratitude to those who, somehow or other, helped me throughout all my Ph.D. years and made this thesis possible. First of all, I would like to thank to my supervisor, Dr. Ir. Aiko Pras, for his careful and patience guidance during all my study years. He gave me the opportunity to enroll as a Ph.D. student in the DACS group, which I am extremely grateful. I also would like to thank to Prof. Dr. Ir. Boudewijn R. Haverkort for his great advice and extreme professionalism. Not the least, I thank all DACS group members for having taken me and helped me during all these years. I would like to thank the members of my graduation committee: Prof. dr. Lisandro Z. Granville, Dr. hab. Olivier Festor, Prof. dr. ir. Cees Th.A.M. de Laat, Prof. dr. Antonio Liotta, Prof. dr. ing. Paul J.M. Havinga, and Prof. dr. Hans van den Berg. I am really grateful for your time spent reviewing this thesis. Special thanks to Lisandro for his valuable help during the third year of my Ph.D. trajectory. The flow analysis performed in this thesis would not have been possible without the cooperation of SURFnet, GÉANT, and the ICTS department of the University of Twente. Special thanks to Hans Trompert (SURFnet), Maurizio Molina (GÉANT), and Roel Hoek (ICTS) for their helpful contribution in the flow collection process. Last, but by no means least, I also thank my colleagues of the EMANICS project by their valuable collaboration. I also extend my gratitude to all my friends who made my staying here in Enschede more enjoyable. Coffee breaks, parties in Macandra, Grolsch tours, social events, dinners or simply "een biertje in de stad", all these events would not be as much fun without you. With this respect, I would like to particularly mention