Networks can be either wired or wireless. Specialised network hardware is required to create both types of networks.

A Network Interface Card (NIC) is a piece of hardware inside a device that allows it to connect to networks.

NICs exist for both wired and wireless networks.

A router transmits data between different LANs.

A switch is a component of a wired LAN which sends data packets to devices on its network.

A Wireless Access Point is essentially a switch for a wireless network.

The acronym "WAP" is sometimes used in place of "Wireless Access Point", although we will refrain from using the short form version in this revision guide.

Fun fact: your home broadband router is actually also acting as a switch and a Wireless Access Point.

There are two types of cable used to transmit data in wired networks: copper wires and fibre-optic cables.

Table 1 shows the comparison of copper wires and fibre-optic cables.

Table 1

	Copper wires	Fibre-optic cables
Carries...	Electricity	Light
Transfer speeds	Slower (up to 10 Gb/s)	Faster (up to 100 Tb/s)
Cost	Cheaper	More expensive
Interference	Some interference	No interference

A Wireless LAN (WLAN) is a local wireless network.

Wi-Fi, the most well-known example of a wireless network, is a specific family of WLAN protocols.

Wireless networks use radio waves or microwaves to transmit data.

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What are the advantages and disadvantages of wireless networks?

Advantages:
• Wireless networks can be more convenient because you can move around while connected
• New devices can be easily added to a wireless network at no extra cost

Disadvantages:
• Wireless communications can be intercepted by hackers so they are less secure
• Wireless networks are more susceptible to interference from nearby networks
• Radio waves can be blocked by physical obstacles which can reduce signal strength
• Wireless networks typically offer lower bandwidth and therefore lower data transfer speeds

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