Networks: Types and Topologies

LAN vs WAN

• LAN (Local Area Network) – small area (home, school, one site); the owner controls the hardware.
• WAN (Wide Area Network) – large geographic area; uses third-party infrastructure (the internet is the biggest WAN).

Wired vs wireless

	Wired (Ethernet)	Wireless (Wi-Fi)
Speed	Faster	Slower
Security	More secure	Less secure
Reliability	More reliable	Interference possible
Convenience	Cabled	Mobile, no cables

Topologies

• Star – every device connects to a central switch. Reliable (one cable fault affects one device) but depends on the central point. Easy to add devices.
• Mesh – devices connect to many others; data can take multiple routes, so it's very robust but expensive to cable.

Hardware

• NIC (network interface card), switch (directs data within a LAN), router (connects networks / to the internet), WAP (wireless access point).

Performance factors

Bandwidth, number of users, wired vs wireless, interference, transmission media.

Exam tip

The internet is a WAN; home Wi-Fi is a LAN. A star topology's single point of failure is the central switch.