- network: interconnects devices
- personal area network: PAN
- local area network: LAN
- campus area network: CAN
- metropolitan area network: MAN
- wide area network: WAN
- networks can be used to monitor devices
- Network interface card (NIC)
- no other device should have the same mac address
- vendor code within mac address
- mac address is 48 bits
- divided into vendor code and unique identifier
- subnet masks
- we have ran out of ipv4 devices
- network address translation (NAT)
- ipv4:
$2^32$ - ipv6:
$2^128$ - ethernet switch learns where to send address
- flooding: when a switch doesn't know where to send, sends to all ports except the one that recieved the frame