Systems on a chip (SOCs) are rapidly evolving into larger networks on a chip (NOCs). This work presents a new methodology for managing power consumption for NOCs. Power management problem is formulated using closed-loop control concepts, with the estimator tracking changes in the system parameters and recalculating the new power management policy accordingly. Dynamic voltage scaling and local power management are formulated in the node-centric manner, where each core has its local power manager that determines units power states. The local power manager?s interaction with the other system cores regarding the power and the QoS needs enables network-centric power management. The new methodology for power management of NOCs is tested on a system consisting of four satellite units, each with the local power manager capable of both node and network centric power management. The results show large savings in power with good QoS.