1. Faculty of Information Technology and Electrical Engineer, University of Oulu, Oulu, Finland
2. Communications and Networking Department, ICTFicial Oy, Espoo, Finland
3. Research and Development Department, OneSource, Coimbra, Portugal
4. Department of Informatics and Telematics, Harokopio University, Kallithea, Greece
5. Department of Computer Science, University of Pisa, Pisa, Italy
6. Department of Electrical and Computer Engineering, University of Western Macedonia, Kozani, Greece
7. Network Technologies Lab, Futurewei, Santa Clara, CA, USA