Certain aspects of a method and system for a power control based on application awareness in a packet network switch are provided. Data communication flow may be monitored in ports in a packet network switch based on packet classification. Ports where data flow is not detected may have at least some functionality disabled to reduce power consumption. In this regard, a power saving mode may be utilized for disabling at least some functionality in a switch port, such as Ethernet ports, for example. A partially disabled port may be fully enabled when monitoring detects active data communication flow in that port. Port functionality may be enabled or disabled sequentially, for example. In some instances, a physical layer portion of the packet network switch may be utilized to adjust power in a port based on the data communication flow.