Classification of Network

Classification of Computer Networks

(A) Based on network physical geographical size/area and the area they cover, computer networks are classified into the following types: –

This is one of the most common types of computer networks.

(1.) Personal Area Network(PAN) 

(2.) Local Area Network(LAN) 

(3.) Metropolitan Area Network(MAN)

(4.) Wide Area Network(WAN)

(5.) Global Area Network(GAN)

(1.) Personal Area Network(PAN)

• Scope: It covers a very small area, typically within a range of a few meters.
• Purpose: It is used for communication between personal devices like smartphones, laptops, tablets, and wearable devices.
• Examples:
  • Bluetooth connections between a smartphone and a wireless headset.
  • USB-connected devices like printers or external hard drives.
• Characteristics:
  • It has low power consumption.
  • It has short-range communication.
  • It is often used for personal convenience.

(2.) Local Area Network(LAN)

Definition

• • LAN is a type of computer network in which several computers are connected properly with each other located within the specific geographical area of diameter 2 km (such as in the same room, on the same floor or in the same building or in the same campus that are connected) to form a single network as to share different computer resources by each one(such as disk drives, printers, data, CPU, fax/modem, applications etc.).

Characteristics/Features

• • Local Area Network is a computer network that spans over a relatively small area. It is confined to small areas, i.e., it connects several devices over a distance of 0 to 5 km. 
  • Most LANs are confined to a single building or group of buildings within a campus. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves.
  • Most LANs connect/use workstations and personal computers.
  • Each node (individual computer) in a LAN has its own CPU, which executes its own programs, but it is also able to access data and devices anywhere on the LAN, i.e., many users can share data as well as expensive devices, such as laser printers, fax machines, etc.
  • Users can also use the LAN to communicate with each other by sending e-mail or engaging in chat sessions.
  • There are many different types of LANs, Ethernet being the most common and widely used for PCs.
  • The most widely used and dominant LAN type is the Ethernet LAN, which is based on the bus topology.
  • LANs are private networks, hence not subject to tariffs or other regulatory controls. For the Wireless LANs, there are additional regulations in several countries.
  • They are the smallest computer networks.
  • In LAN, the data transmission speed is high when compared to the typical WAN (normal 2 to 100 MB /sec or up to 1Gbps latest).
  • It normally uses a Bus & Ring topology in its structure.
  • There are different types of Media Access Control methods applied in a LAN to access or share the data, in which the common/popular ones are Bus-based Ethernet, Token Ring, etc.
  • LANs are capable of transmitting data at very fast rates, i.e., much faster than data can be transmitted over a telephone line, but the distances are limited.
  • They use mostly inexpensive equipment.
  • They have low error rates.
  • The transmission speeds in this network range from 10Mbps to 100Mbps. But nowadays, 1000 Mbps/more are available.
  • Structures:
    • There are five major components present in a typical LAN:
      i) Basic Network devices – The Nodes, Workstations, printers, and file servers, which are the basic components of the network and are normally accessed by all other computers of the network.
      ii) Network Communication Devices – These devices are used to connect each basic component of the network. Here, several Intermediate nodes/devices (such as repeaters, bridges, and hubs/switches) allow them to be connected together to form larger LANs. A LAN may also be connected to another LAN or to WANs and MANs using a Router device.
      iii) Network Interface Cards (NICs) – This hardware device is required to access the network. It is the interface between the machine and the physical network.
      iv) Cable – This is used as a physical transmission medium. However, present-day LAN may not require the physical transmission media. It may be a Wireless LAN.
      v) Network Operating System – This software application is required to control the functioning of network operations and administration.

Advantages

• • It allows sharing of expensive resources among network components such as printers, software, and mass storage devices.
  • Comparatively less complex structure, hence low setup cost.
  • LAN allows high-speed exchange of essential information.
  • It contributes to increased productivity.

Disadvantages

• • Some type of security system must be implemented if it is important to protect confidential data in a LAN.
  • The security may be further lowered if it is a wireless LAN.
  • LAN is restricted to a small area only.
  • The distances are limited in LAN, and there is also a limit on the number of computers that can be attached to a single LAN.

Uses

• • LANs are typically installed in offices, businesses, colleges & universities, etc.

(3.) Metropolitan Area Network(MAN)

Definition

• • Metropolitan area networks are large computer network that spans a metropolitan area or a city or a large campus, falling between a LAN and a WAN up to 5-50 km.
  • A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities.

Characteristics/Features

• • It was developed in the 1980s.
  • They are medium-sized computer networks, i.e., the network size falls between LAN and WAN.
  • The typical data transmission speed is in the range of 5- 10 Mbps or more.
  • It normally uses the Distributed Queue Dual Bus [DQDB] topology in its structure.
  • This network is normally designed for a city or town.
  • A MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations.
  • MANs might also be owned and operated as public utilities or privately owned as per need. 
  • They usually connect several LANs or local networks of the city and form the MANs.
  • They typically use wireless infrastructure or optical fiber connections to link their sites/components.
  • The common devices used are a modem, a router, and wireless media/cable.

Advantages

• • A MAN often acts as a high-speed network to allow the sharing of regional resources.
  • It is also frequently used to provide a shared connection to other networks using a link to a WAN.

Disadvantages

• • It is difficult to manage.
  • It is difficult to make the system secure from hackers. 

Uses

• • MANs are typically installed in the city to connect the various LAN branches of an organization, banks, businesses, etc.

(4.) Wide Area Network(WAN)

Definition

• • The Wide Area Network is the largest network system connecting cities, countries, or continents, LANs, MANs, or WANs using routers and public communications links, and covers the whole world/earth.
  • WAN is a network that covers a large geographical area and covers different cities, states and sometimes even countries, is known as WAN.  

Characteristics/Features

• • The largest and most well-known example of a WAN is the Internet.
  • The typical data transmission speed is in the range of 256Kbps- 2 Mbps or more.
  • It normally uses ATM, Frame Relay, Sonet type of topology in its structure.
  • Many WANs are built specifically for one particular organization and are private.
  • Many other WANs are built by Internet service providers, which provide connections from an organization’s LAN to the Internet.
  • Communication medium used in WANs may be satellite, public telephone networks, which are connected by routers.
  • Structures:
    • WANs are often built using leased lines. At each end of the leased line, a router connects to the LAN on one side and a hub/switch within the WAN on the other. Leased lines can be very expensive.
    • WANs can also be built around a public network or the Internet.

Advantages

• • It covers the largest geographical area.
  • It is a large place for sharing software & resources.
  • It distributes the workload.

Disadvantages

• • It requires the costliest setup.
  • WAN has more security problems compared to MAN and LAN.
  • It needs a dedicated firewall and antivirus software for security purposes.
  • It has tough troubleshooting. 

Uses

• • WANs are used to connect several LANs, MANs, and even WANs together, so that users and computers in one location can communicate with users and computers in other locations.
  • WANs are typically installed anywhere in the world to connect the various LANs/MANs and even WAN branches of the same or different organizations, Banks, businesses, Institutions, Government departments, etc, via the internet/satellite/public network.

(5.) Global Area Network(GAN)

• Scope: It covers an entire global region or multiple continents.
• Purpose: It connects networks across the globe, often using satellite links or undersea cables.
• Examples:
  • International banking systems.
  • Global corporate networks.
• Characteristics:
  • It is an extremely large-scale network.
  • It requires sophisticated routing and management systems.
  • It often involves collaboration between multiple ISPs and organizations.