Types of Networks: From Your Home Wi-Fi to the Internet Backbone

1. Network types by scope

The most classic way to classify networks is by their size and geographical scope. Think of this as the map’s “zoom levels.”

1.1 PAN – Personal Area Network

A PAN is your personal connectivity bubble:

• Bluetooth between your laptop and headphones
• Smartwatch syncing with your phone
• Wireless keyboard/mouse

As a sysadmin you usually won’t manage it, but it coexists with everything else.

1.2 LAN – Local Area Network

The LAN is the classic local network:

• Covers an office, floor, house, or small shop
• High speed (1 Gbps, 10 Gbps...)
• Low latency (< 1 ms typically)
• Managed by the company’s IT/network team

1.3 WLAN – Wireless LAN

The WLAN is basically a LAN with Wi-Fi:

• Uses IEEE 802.11 standards (a/b/g/n/ac/ax...)
• Combines cabling (backbone) with access points
• Handles authentication and encryption (WPA2/WPA3, 802.1X)

1.4 CAN – Campus Area Network

A CAN links multiple LANs inside a campus:

• Several buildings in a university
• Industrial park with multiple warehouses
• Headquarters made up of separate buildings

1.5 MAN – Metropolitan Area Network

A MAN covers a city or part of it:

• Networks connecting branches in the same city
• Provider infrastructure for metropolitan dedicated links

1.6 WAN – Wide Area Network

The WAN is the long-distance network:

• Connects cities, countries, or continents
• Internet is the most well-known example
• Higher latency, more expensive links
• More dependencies on third parties (ISPs, telcos)

1.7 GAN – Global Area Network

The GAN label is used for truly global networks:

• Backbones of large international telcos
• Cloud provider networks (Google, AWS, Azure)
• Low-orbit satellite networks (Starlink, etc.)

Scope summary

2. Network topologies: how nodes are connected

Topology describes how devices are connected physically (or logically). In modern networks, most topologies are more conceptual than physical, but they’re still useful to understand design and failure modes.

       [Switch]
        /  |  \
      PC1 PC2 PC3

      PC1 — PC2
       |  \/  |
       |  /\  |
      PC3 — PC4

3. Physical vs logical networks

As networks grew, we split physical from logical structure:

• Physical: Cables, ports, switches, routers
• Logical: VLANs, subnets, routes, policies, overlays

3.1 VLANs: multiple logical networks on one physical network

# Typical switch configuration
Switch(config)# vlan 10
Switch(config-vlan)# name USERS
Switch(config)# vlan 20
Switch(config-vlan)# name SERVERS
Switch(config)# vlan 30
Switch(config-vlan)# name VOIP

Key benefit: Isolation and security. A broadcast storm in VLAN 10 doesn’t affect VLAN 20.

3.2 Overlays: VPN, VXLAN, SD-WAN

They create a “virtual network” on top of the physical one:

• Site-to-site VPN: Connect offices as if they were on the same LAN
• VXLAN: Scale VLANs beyond physical limits (critical in cloud)
• SD-WAN: Dynamically choose between MPLS, Internet, LTE based on quality/cost

4. Real-world practical scenarios

5. What kind of network do I need? Key questions

There’s no such thing as “the perfect network,” but there are the right questions:

1. Geographical scope? Single office, multiple cities, global?
2. Required availability? 99.9% or 99.999% (five nines)?
3. Is latency critical? Trading, VoIP, video conferencing?
4. Expected growth? 50 users today, 500 in 2 years?
5. Security segmentation? PCI-DSS, HIPAA, ISO 27001?
6. Budget? Expensive MPLS or SD-WAN over the Internet?