Power-saving network switching device

A network switching device includes packet switching means and clock signal providing means. The packet switching means receive packets sent from any of the plurality of lines, determines forwarding destinations for the received packets, and forwards the received packets. The packet switching means operates synchronized with a provided clock signal. The clock signal providing means provides the clock signal to the packet switching means. The clock signal providing means is capable of switching a frequency of at least a portion of the clock signal for being provided to the packet switching means to multiple different values.