Back-up power for a network switch

A network switch includes a power connection configured to receive power from a primary power source and at least two ports. At least a first one of the ports is configured to connect to a first network interface of a first computing device through a communication medium configured to conduct operating power for the network switch. The first network interface is configured to draw electrical power from a power supply of the first computing device and provide, through the network cable, at least a portion of the drawn electrical power as the operating power. A switching circuit is configured to route network data between the ports and a power management circuit coupled at least to the first port. The power management circuit is configured to draw at least a portion of the operating power from the first port, and power the switching circuit using the drawn power responsive to a detected failure of the primary power source.