Network hardware
Introduced| English | Meaning |
|---|---|
| network interface card/ˈnetwɜːk ˈɪntəfeɪs kɑːd/ | Hardware that provides a computer with a connection to a network. |
| MAC address/mæk əˈdres/ | A link-layer identifier used to address a network interface within a local network. |
| IP address/ˌaɪ ˈpiː əˈdres/ | A numerical address used to identify and route traffic to an interface on an Internet Protocol network. |
| router/ˈruːtə/ | A network device that forwards packets between networks using destination addresses and routing information. |
The boxes that connect us
- To join a network, a device needs a network interface card 网络接口卡.
- Devices are identified by a MAC address MAC地址 and an IP address 网际协议地址.
- A router 路由器 connects different networks together.
Network route lab
Follow data from a device through network hardware and protocols.
Network interface card (NIC)
- A NIC is the hardware that lets a device join a network and send/receive data.
- Each NIC has a built-in MAC address.

Inside a hard disk drive (HDD): the shiny disk spins and the arm reads the magnetised data

A digital camera: a lens focuses light onto a sensor that records the pixels
Match each piece of network hardware to its job.
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A NIC joins a device on; a switch forwards inside the LAN; a router joins networks; the MAC is the device's fixed ID.
MAC address vs IP address
- A MAC address identifies one physical device. The maker sets it, it does not normally change, and it is written in hexadecimal.
- An IP address identifies a device on a network. It is given by the network and can change.
- So the MAC stays with the device; the IP depends on the network it's using.

An optical mouse: a light and a sensor track its movement on the desk
Which is true of a MAC address compared with an IP address?
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The MAC stays with the device (set by the maker, written in hex); the IP depends on the network and can change.
A MAC address is normally written in denary (base 10).
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False. A MAC address is normally written in hexadecimal pairs, such as AC:DE:48:00:11:22.
A device's IP address is fixed when it is made and never changes.
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False. The IP address is assigned by the network the device joins, so it can change. The MAC address is the one set at manufacture.
Router
- A router connects different networks together — e.g. your home network to the internet.
- It reads the IP address in each packet and forwards it towards the right network.

A laser printer uses a laser and powder (toner) fixed onto paper by heat
A router:
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A router joins networks (e.g. home to internet) and forwards each packet using its destination IP.
You've got it
- a NIC lets a device join a network and holds its MAC address
- MAC = fixed to the physical device (hex, set by the maker); IP = from the network, can change
- a router connects networks and forwards packets by their IP address