The Optimization and Networking Cluster (ONC) is a research group within the Networks and Computer Science Department at TELECOM ParisTech. Prior to 2009, this research group, formerly known as Optical Cluster, has conducted studies and investigations on long-haul optical networks. These investigations covered a large research area in optical WDM networks ranging from network planning to traffic engineering with a special focus on Network Protection, Traffic Grooming, and Quality of Transmission. In 2007, this research group has been interested by the emerging research topics in Cloud environment. In 2009, the research group has been reorganized and its domain of interests enlarged covering new topics such as Radio over Fiber, Green Networking, and Smart Grids. ONC is led by Professor Maurice Gagnaire assisted by two senior research engineers. Many of the research works involve multiple international collaborators as well as local Ph.D. and M.Sc. students. ONC is currently contributing to multiple national and European projects such as CompatibleOne, EasiCloud, TeleWatt, …