Routelearn.net
Course menu

Unit 1: Networking BasicsLesson 1.3 (3 of 4 in this unit)3 of 84 in the Network Fundamentals course

Types of LANs

Home, office, campus, wireless and data-centre LANs, and how they differ from WANs.

Beginner · 6 min read

A LAN (local area network) is a network that connects devices within a limited area, such as a home, an office, a campus or a data centre, and is usually owned and run by one organisation. LANs range from small SOHO networks to enterprise campuses built in access, distribution and core layers.

In simple terms: A LAN is the network in one place, such as your home or office. It connects the computers, phones and printers there, and reaches the internet through a router.

LAN vs. the other "-ANs"

TypeCoversTypical technologyWho owns it
PAN (personal)A few metres around one personBluetooth, USBThe user
LAN (local)A home, office, floor or buildingEthernet, Wi-FiThe organisation
MAN (metropolitan)A cityMetro Ethernet, fibre ringsUsually a provider
WAN (wide)Cities, countries, the internetMPLS, internet VPNs, leased linesProviders; the organisation rents the links

A LAN has three key traits: one organisation controls it, it covers a limited area, and it offers high speed at a low cost per bit.

SOHO LAN: small office / home office

PCPhoneAll-in-one routerswitch + AP + routerISP
  1. 1. One box does everything. A few wired and wireless devices share a single box that is a switch, a Wi-Fi access point and a router at the same time.

Enterprise campus LAN

A larger organisation builds its LAN in tiers(layers), so the network can grow and keep working when a device or link fails:

Corefast transportDistributionDistributionAccessAccessAccessAP
  1. 1. Access layer: where PCs, phones, printers and access points connect. Typical features: PoE, VLAN assignment and port security.
  2. 2. Distribution layer: connects (aggregates) the access switches. Typical features: routing between VLANs, security policy and redundancy.
  3. 3. Core layer: fast, highly available transport between distribution blocks. Smaller campuses combine the core and distribution layers (a collapsed core).

Wireless LAN (WLAN)

A WLAN (wireless LAN) uses IEEE 802.11 (Wi-Fi) instead of cables for the last few metres to the user. Access points connect wireless clients to the wired Ethernet LAN. In larger networks, a wireless LAN controller (WLC) manages the access points centrally.

Data centre LAN

Data centres connect servers rather than users, and most of the traffic flows between servers. Modern designs use a spine-and-leaf topology: every leaf (rack) switch connects to every spine switch. As a result, traffic between servers in any two racks crosses the same number of switches (leaf, spine, leaf).

Check yourself

Predict · scenario 1

A new employee plugs a PC and an IP phone into the wall socket in a three-tier campus network. Which layer do they connect to?

Predict · scenario 2

A company has an office network in London and connects it to its Paris office over a provider's link. What usually distinguishes the office LAN from the WAN link?