Types of Computer Network and Network Architecture

Types of Computer Network

On the basis of their size, physical division, and their geographical division, computer networks can be categorized into three types. They are:
  1. Local Area Network (LAN)
  2. Metropolitan Area Network (MAN)
  3. Wide Area Network (WAN)

a. Local Area Network (LAN)

The computer network which is limited to a small area such as a room a building or a school and connects a limited number of computers is called Local Area Network (LAN). We can use a large number of computers in a LAN but it is restricted to a small geographical area. Local Area Networks are limited by distance. In order to keep the signal at a quality transmission level, it must be boosted by repeaters along the way. By creating a LAN, we can share resources such as hardware and software to transfer information between the computers. In a LAN, computers and other hardware such as printers can be connected by cable (copper wiring), fiber optic cabling (glass fibers).
lan diagram hand drawn

Features of LAN

  • It covers a limited geographical area of about a few kilometers.
  • It offers a high-speed data transfer rate of about 10 to 100 Mbps (Megabits per second)
  • It is normally owned by a single organization.
  • It provides full-time connectivity to local services.
  • It uses guided transmission media.
  • It is unaffected by any environmental factors.

b. Metropolitan Area Network (MAN)

The medium-sized network that covers the area larger than a LAN but smaller than a WAN is called Metropolitan Area Network (MAN). It covers a larger geographical area such as a university, an entire city, a valley, a district, or a zone. This type of network is prepared by connecting several LANs in different locations. To form a MAN, several LANs are connected through a telephone line, optical fiber cable,s or wireless communication media. A MAN is typically owned and operated by a single entity such as a government body or a large corporation. It is specially adapted by medium-sized organizations having different branches within a city or region.
man diagram hand drawn

Features of MAN

  • It covers a larger geographical area than LAN and connects a larger number of computers.
  • It uses cable or wireless communication media to connect computers.
  • It connects multiple LANs in different locations by using Ethernet technology.
  • It is owned by single or multiple organizations.
  • It offers a number of network services compatible with bandwidth from 128 kbps to 1 Gbps.

c. Wide Area Network (WAN)

The communication network, that spans globally and connects a large number of computers around the world is called Wide Area Network. It is the largest network in the world. It is not restricted to a geographical location. The Internet is an example of a WAN. To form a WAN, several LANs and MANs are connected through satellite links or microwave systems. These networks have become quite necessary in the current era, where day to day activities of many business organizations are spread. WANs are used by many companies for transmitting and receiving information among workers, customers clients, etc. across cities, regions, and countries. This technology is of high speed and very expensive to set up.
wan diagram hand drawn

Features of WAN

  • It is not restricted to a geographical location. It covers the whole world.
  • It uses satellite links or microwave systems to connect several LANs and MANs.
  • It is owned by multiple organizations.
  • This technology is of high speed and very expensive to set up.
  • Data Transmission in WAN is slower than LANs and MANs.

Network Architecture

Network architecture describes how the computers on the network interact and communicate with each other. It is the combined form of network topologies and mode of data transmission between the computers in the network.
Generally, network architecture can be classified into two types:
  1. Client-server network architecture
  2. Peer-to-peer network architecture
  3. Centralized network architecture

a. Client-server network architecture

The network mode in which there is at least one server and other clients is called a client-server model. This is a more common type of network architecture that uses a central server and specified network software. The server is dedicated and is only used to store files and run server tasks. The computers that connect to the server are called clients. In this network, each client can share the processing and storage with the server. The server provides the services to the clients whereas clients request the server for services. The server provides the services to the clients whereas clients request the server for services. The server should be a powerful computer with greater processing speed and large storage capacity than the client. Depending on the type of work the server may be of various types such as File server, Printer server, Message server, Application server, Web server, etc. In short, the client-server networks provided easier network administration with secure and manageable access to company data.
client server network hand drawn

Advantages of Client-Server Network

Some advantages of client-server network are as follows:
  • A client/ server network covers a larger geographical area.
  • The cabling scheme can range from the simplest to the most complicated one.
  • It reduces t network traffic.
  • It centralized the network management and security to the server.

Disadvantages of Client-Server Network

  • Too many requests from the clients and overload can lead to breaking-down of the server system.
  • In a client-server system, if the server fails, the whole network goes down.
  • It is very expensive to install and manage this type of network.
  • Needs professional manpower to maintain the servers and other technical details of the network.

b. Peer-To-Peer Network Architecture

The Peer-To-Peer is a type of network architecture consisting of several computers which are connected to each other. In this type of network, all the computers function both as a client and a server, in which, each computer has equal responsibilities of providing and using resources. It has no central data storage.
The Peer-To-Peer network consists of shared folders located on computers within the network. These folders are set to shared status so that other people connected to the network can access them. Each shared folder is accessed by the users of the network, who set up a certain drive letter (say H:) as a p[ointer to be shared folders on the other computers. In addition, any printers connected to any computer can be shared with other network users.
peer to peer network hand drawn

Advantages of a Peer-To-Peer Network

Some advantages of peer-to-peer networks are as follows:
  • All the resources and contents are shared by all the peers (clients).
  • It is more reliable as central dependency is eliminated. Failure of one peer doesn’t affect the function of other peers.
  • There is no need for a full-time system administrator because each user can control their shared resources.
  • The overall cost of building and maintaining this type of network is comparatively less.

Disadvantages of a Peer-To-Peer Network

  • In this network, the whole system is decentralized thus it is difficult to administer.
  • Security in this system is very less.
  • Data recovery or backup is very difficult since each computer should have its own backup system.

c. Centralized Network architecture

Central network architecture is a type of network where all users connect to a central server, which is the acting agent for all communications. This server would store both the communications and the user account information. Most public instant messaging platforms use a centralized network. So it is called centralized server structure.
centralized network hand drawn

Advantages of Centralized Network architecture

  • Centralized data management: In a centralized network computing model, data is stored on the server. This increases the reliability of data because all data modifications are stored at a central location.
  • High level of security: The centralized network computing model is a highly secure network model. This is because network security can be implemented and monitored centrally from the server.
  • Cost-effectiveness: High-end investment is required for establishing a high-capacity and secure server. On the other hand, clients require very low investment. This reduces the overall cost of setting up a centralized network.

Disadvantages of Centralized Network architecture

  • Low performance and network speed: The centralized network computing model consists of a server that manages numerous requests, simultaneously. This increases network traffic, consequently reducing the speed and performance of the network.
  • The central point of failure: The server is the central place for storing data and processing all client requests. If the server fails, the functioning of the entire network is disrupted.

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