A network can be as small as two devices connected by Bluetooth or as large as the Internet connecting billions of devices.

The main types of computer networks are:

• PAN (Personal Area Network)
• LAN (Local Area Network)
• CAN (Campus Area Network)
• MAN (Metropolitan Area Network)
• WAN (Wide Area Network)
• WLAN (Wireless Local Area Network)

YOU
│
├── Talking to yourself or your smartwatch → PAN
│
├── Talking to your family inside your house → LAN
│
├── Talking to everyone in your city → MAN
│
└── Talking to people across the world → WAN (Internet)

A Personal Area Network (PAN) is the smallest type of network.

It connects devices that belong to a single person within a very short distance (typically a few meters).

Your: Phone, Smartwatch, Wireless earbuds, Bluetooth speaker are all connected together.

                       Smartwatch
                            |
                            |
Wireless earbuds -------- Phone -------- Bluetooth speaker

• Usually 1–10 meters.

• Bluetooth
• NFC (Near Field Communication)
• USB (Universal Serial Bus)
• Infrared (older devices)

• Wireless headphones
• Smartwatches
• Fitness trackers
• Wireless keyboards and mice
• File sharing between nearby devices

• Smallest type of network
• Connects personal devices
• Low power consumption
• Easy to set up
• Usually wireless

• Easy to configure
• Low cost
• Portable
• Energy efficient

• Limited range
• Limited number of devices
• Lower speed than LAN

A Local Area Network (LAN) connects devices within a small geographic area.

Examples include:

• Home
• School
• Office
• College
• Computer Lab

Your home Wi-Fi.

                Internet
                   │
                 Router
        ┌──────────┼──────────┐
        │          │          │
     Laptop      Phone       T.V
        │
    Gaming PC

All devices are connected through the same router.

They can:

• Share files
• Print documents
• Access the Internet
• Play multiplayer games
• Stream media

• Home
• Office
• School
• Building
• Up to a few kilometers

• Ethernet
• Wi-Fi
• Fiber Optics
• Switches
• Routers

• Homes
• Schools
• Offices
• Computer labs
• Gaming cafés

• High-speed communication
• Low latency
• Privately owned
• Easy to manage
• Supports many devices

LAN provides very fast communication between connected devices, making file transfers and data sharing efficient.

Example: Transferring a 2 GB file between two office computers takes only a few seconds.

Multiple users can share hardware resources such as printers, scanners, storage devices, and a single Internet connection.

Example: All employees in an office use the same network printer instead of having individual printers.

Users can quickly share files and folders without using external storage devices.

Example: Students in a computer lab access study materials from a shared server.

Network administrators can manage users, devices, software, and security from a central location.

Example: An IT administrator installs software updates on all office computers from one server.

Sharing resources reduces the overall cost of hardware and maintenance.

Example: A school purchases one high-speed printer instead of buying a separate printer for every classroom.

Since devices are located close to each other, communication delays are minimal.

Example: Multiplayer games played over a LAN have much lower delay than online games over the Internet.

Users can collaborate easily by accessing shared files and applications.

Example: Team members work together on documents stored on a shared network drive.

A LAN is designed for a small geographic area such as a home, office, or school.

Example: Your home Wi-Fi cannot directly connect to another house several kilometers away.

Setting up a LAN requires networking equipment such as routers, switches, cables, and access points.

Example: A new office must purchase networking hardware before employees can connect.

The network requires regular monitoring, updates, and troubleshooting to ensure reliable performance.

Example: An administrator periodically updates the router firmware and replaces faulty network cables.

If a LAN is not properly secured, unauthorized users may gain access to shared resources.

Example: A weak Wi-Fi password could allow strangers to connect to the office network.

If a critical networking device fails, multiple users may lose network access.

Example: If the main switch stops working, all connected computers lose communication with each other.

Performance may decrease when many devices use the network simultaneously.

Example: During office backups, file transfers become slower because many computers are sending data at the same time.

A Campus Area Network (CAN) is a network that interconnects multiple Local Area Networks (LANs) across a campus or organization. It covers a larger area than a LAN but a smaller area than a Metropolitan Area Network (MAN).

A CAN is like building private roads that connect all those houses together so everyone can easily travel and share resources.

House 1 ----\
             \
House 2 ------ Main Campus Road ---- House 3
             /
House 4 ----/

Similarly,

LAN 1 ----\
            \
LAN 2 ------- Campus Backbone ------- LAN 3
            /
LAN 4 ----/

Each building has its own LAN.

These LANs are connected using high-speed fiber optic cables through routers and core switches.

                     Internet
                         │
                   Core Router
                         │
                   Core Switch
            ┌────────────┼─────────────┐
            │            │             │
      Engineering     Library     Administration
            │            │             │
           LAN          LAN           LAN

Typically covers:

• University campuses
• College campuses
• Corporate campuses
• Hospital campuses
• Military bases

Typical Range: Approximately 1–10 km

• Ethernet
• Fiber Optic Cable
• Layer 2 Switches
• Layer 3 Switches
• Routers
• VLAN
• Wi-Fi Access Points

• Universities
• Colleges
• Corporate office campuses
• Hospitals
• Industrial parks
• Military bases
• Research centers

• Larger than a LAN
• Smaller than a MAN
• Connects multiple LANs
• Privately owned and managed
• High-speed communication
• Uses a central backbone network
• Reliable and secure
• Commonly uses fiber optic connections

Fiber optic connections provide fast communication between buildings.

Buildings can share servers, printers, databases, and Internet connections.

The entire campus network can be managed from a central IT department.

Instead of maintaining separate networks, resources can be shared across the campus.

Departments in different buildings can easily communicate and exchange information.

Fiber optic cables, routers, and core switches are expensive to install.

Designing and managing a campus-wide network requires skilled network administrators.

Hardware failures or cable damage can affect multiple buildings.

If not properly secured, unauthorized access could spread across the entire campus.

A Metropolitan Area Network (MAN) is a computer network that connects multiple LANs or CANs across a city or metropolitan area. It is larger than a CAN but smaller than a Wide Area Network (WAN).

Think of a city with many neighborhoods.

Each neighborhood has its own roads (LAN).

A MAN is like the city's main road network that connects all neighborhoods together.

Neighborhood A
       │
       │
Main City Road
       │
Neighborhood B
       │
Neighborhood C

Similarly,

LAN A
   │
   │
City Fiber Network
   │
LAN B
   │
LAN C

Typically covers:

• A city
• Metropolitan area
• Large municipality

Typical Range: Approximately 5–50 km

• Fiber Optic Cable
• Metro Ethernet
• MPLS (Multiprotocol Label Switching)
• Ethernet
• Routers
• Layer 3 Switches
• DWDM (Dense Wavelength Division Multiplexing)

• Banks with multiple city branches
• Universities with multiple campuses
• Hospitals across a city
• Government offices
• Internet Service Providers (ISPs)
• Cable TV providers
• Smart city infrastructure

• Larger than CAN
• Smaller than WAN
• Connects multiple LANs and CANs
• High-speed communication
• Often uses fiber optic infrastructure
• Can be privately or publicly managed
• Suitable for city-wide communication

• High-Speed Communication
• Efficient Resource Sharing
• Centralized Management
• Scalable
• Cost-Effective for Large Organizations

• Expensive Infrastructure
• Complex Management
• Security Challenges
• Dependency on Backbone Network

WAN (Wide Area Network) is a type of computer network that connects devices, smaller networks (LANs), or organizations across a large geographical area such as cities, countries, or even continents.

A WAN allows different locations to communicate and share resources even when they are far apart.

Think of a company that has offices in:

Kathmandu Office
        |
        |
  WAN Connection
        |
        |
Pokhara Office
        |
        |
  WAN Connection
        |
        |
New York Office

Each office has its own LAN, but WAN connects those LANs together so employees can access the same systems, files, applications, and databases.

Imagine a country's highway system.

• LAN = Roads inside a city
• MAN = Highways connecting nearby cities
• WAN = International highways connecting different countries

WAN is like the global transportation network that allows people and goods to move between distant locations.

• Countries
• Continents
• Worldwide

• Fiber Optic Cables: High-speed cables that transmit data using light.

• MPLS (Multiprotocol Label Switching): A technology used by enterprises to create private WAN connections.

• VPN (Virtual Private Network): Creates a secure connection over the public Internet.

• Leased Lines: A dedicated communication link rented from a telecom provider.

• SD-WAN (Software Defined WAN): A modern WAN technology that manages multiple connections using software.

• Connecting Branch Offices
• Internet Access
• Cloud Computing
• Remote Work
• Online Banking

• Large Geographic Coverage
• Connects Multiple LANs
• Uses Public and Private Infrastructure
• High Complexity
• Lower Speed Compared to LAN

• Global Connectivity
• Resource Sharing
• Centralized Network Management
• Supports Remote Access
• Enables Global Communication
• Scalability for Growing Organizations
• Reliable Data Exchange

• High Installation and Maintenance Cost
• Higher Latency
• Security Vulnerabilities
• Complex Network Management
• Dependency on Service Providers
• Requires Skilled Administrators
• Lower Speed Compared to LAN
• Network Failure Impact

WLAN (Wireless Local Area Network) is a type of local network that connects devices within a limited area using wireless communication technologies instead of physical cables.

WLAN allows devices like laptops, smartphones, tablets, and printers to communicate and access network resources through wireless signals.

• Home Wi-Fi network connecting smartphones, laptops, and smart TVs
• Office wireless network connecting employees' devices
• School or university Wi-Fi network
• Public Wi-Fi hotspots in cafes, airports, and hotels

              WLAN (Wireless Local Area Network)
 
                    Internet
                       |
                       |
                  +---------+
                  | Router  |
                  +---------+
                       |
                       |
              +----------------+
              | Wireless       |
              | Access Point   |
              | (Wi-Fi)        |
              +----------------+
                 /      |       \
                /       |        \
               /        |         \
          +-------+ +-------+ +---------+
          |Laptop | |Phone  | |Tablet   |
          +-------+ +-------+ +---------+
 
                 Wireless Signals
              ~~~~~~~~~~~~~~~~~~~~

                 Internet
                    |
                 Router
                    |
              Wi-Fi Signal
          ~~~~~~~~~~~~~~~~~~~
          ~                 ~
      +--------+        +--------+
      | Laptop |        | Phone  |
      +--------+        +--------+
          
      +--------+        +--------+
      | Smart  |        | Printer|
      | TV     |        |        |
      +--------+        +--------+

Devices  →  Wireless Access Point  →  Router  →  Internet

• Home, office, classroom, or small building
• Typically covers around 30–100 meters depending on environment and equipment
• Can be extended using wireless access points and mesh systems

• Wi-Fi (IEEE 802.11 standards)
• Wireless Access Points (AP)
• Wi-Fi 5 (802.11ac)
• Wi-Fi 6 (802.11ax)
• Wi-Fi 6E
• Wi-Fi 7
• Wireless Mesh Networks
• Bluetooth (for short-range wireless connections)

• Home Internet Access
• Office Wireless Connectivity
• Educational Institutions
• Public Wi-Fi Hotspots
• Smart Home Devices
• IoT Device Connectivity
• Wireless Printing and File Sharing

• Uses wireless signals instead of cables
• Provides mobility and flexibility
• Covers a limited geographical area
• Requires wireless access points
• Uses radio frequency communication
• Supports multiple connected devices
• Easier installation compared to wired networks

• Easy Installation
• Mobility and Flexibility
• Reduced Cable Requirements
• Easy Device Connectivity
• Cost Effective Deployment
• Supports Portable Devices
• Easy Network Expansion

• Limited Coverage Range
• Security Risks
• Signal Interference
• Lower Speed Compared to Wired Networks
• Connection Stability Issues
• Requires Regular Security Updates
• Performance Decreases with More Devices