Network Switch
While routers server as an interface for devices at L3, a network switch uses MAC addresses to forward packets at L2 to a device.
- ex. Switches for Ethernet are the most common form of network switch
- switches are built into residential routers
the internet shares network bandwidth dynamically. Senders push and jostle with each other to get their packets over the wire as quickly as possible, and the network switches decide which packet to send (i.e., the bandwidth allocation) from one moment to the next.