Abstract ITER Plant Systems I&C will be connected to CODAC System via Plant System Host (PSH) and High Performance Networks (HPN). Some functions of CODAC require deterministic, hard real-time communication and synchronization between distributed nodes. These requirements are addressed by the CODAC High Performance Networks. The CODAC network infrastructure is being defined including space allocation for backbone cable termination as well as housing network equipments in different ITER plant buildings, cable trenches, network topology and backbone. The ITER building design is in final stage so the activities in this direction are quite well in advance. Many prototyping and market survey activities leading to technology decisions for High Performance Networks (HPN) have been launched in late 2008. These activities are evaluating different commercial off-the-shelf (COTS) technologies as well as technologies being used in existing fusion and non-fusion experiments. In this paper we provide the current status of activities which are ongoing to define CODAC network infrastructure as well as a report on technology decisions. Finally we provide a plan and roadmap to complete this task of defining CODAC networks and network infrastructure.