What network device directs network traffic?

Switches

Switches are more complicated in that, unlike hubs, they manage network traffic instead of just broadcasting signals.

Each message sent by a computer or peripheral will contain information about which computer it comes from, and which it's meant for, and the switch makes sure the message gets to the correct destination on the local network. If Computer A sends a message to Computer D, a switch will make sure that Computers B and C don't receive it.