A network switch (or just switch) is a networking device that performs transparent bridging (connection of multiple network segments with forwarding based on MAC addresses) at up to the speed of the hardware. Common hardware includes switches, which can connect at 10, 100, or 1000 megabits per second, at half or full duplex. Half duplex means that the device can only send or receive any given time, whereas full duplex can send and receive at the same time.