Computer Network & Its Types | IBPS PO Prelims & Mains Preparation - Bank Exams PDF Download

Computer Network

• Computer Network is a group of computers connected with each other through wires, optical fibres or optical links so that various devices can interact with each other through a network. 
• The aim of the computer network is the sharing of resources among various devices. 
• In the case of computer network technology, there are several types of networks that vary from simple to complex level.

Computer Network Architecture:
Computer Network Architecture is defined as the physical and logical design of the software, hardware, protocols, and media of the transmission of data. Simply we can say that how computers are organized and how tasks are allocated to the computer. 
The two types of network architectures are used:
1. Peer-To-Peer network
2. Client/Server network 

Peer-To-Peer network: 

• Peer-To-Peer network is a network in which all the computers are linked together with equal privilege and responsibilities for processing the data. 
• Peer-To-Peer network is useful for small environments, usually up to 10 computers. 
• Peer-To-Peer network has no dedicated server. 
• Special permissions are assigned to each computer for sharing the resources, but this can lead to a problem if the computer with the resource is down.

Client/Server Network: 

• Client/Server network is a network model designed for the end users called clients, to access the resources such as songs, video, etc. from a central computer known as Server. 
• The central controller is known as a server while all other computers in the network are called clients. 
• A server performs all the major operations such as security and network management.
• A server is responsible for managing all the resources such as files, directories, printer, etc. 
• All the clients communicate with each other through a server. For example, if client1 wants to send some data to client 2, then it first sends the request to the server for the permission. The server sends the response to the client 1 to initiate its communication with the client 2.

Components of Computer Network: Computer network components are the major parts which are needed to install the software. Some important network components are NIC, switch, cable, hub, router, and modem. Depending on the type of network that we need to install, some network components can also be removed. For example, the wireless network does not require a cable.

NIC: 

• NIC stands for network interface card. 
• NIC is a hardware component used to connect a computer with another computer onto a network 
• It can support a transfer rate of 10,100 to 1000 Mb/s. 
• The MAC address or physical address is encoded on the network card chip which is assigned by the IEEE to identify a network card uniquely. The MAC address is stored in the PROM (Programmable read-only memory).

There are two types of NIC: wireless NIC and wired NIC

• Wireless NIC: The wireless NIC contains the antenna to obtain the connection over the wireless network. For example, laptop computer contains the wireless NIC. 
• Wired NIC: The Wired NIC is present inside the motherboard. Cables and connectors are used with wired NIC to transfer data.

Hub: 
Hub is a central device that splits the network connection into multiple devices. When computer requests for information from a computer, it sends the request to the Hub. Hub distributes this request to all the interconnected computers. 

Switches: 
Switch is a networking device that groups all the devices over the network to transfer the data to another device. A switch is better than Hub as it does not broadcast the message over the network, i.e., it sends the message to the device for which it belongs to. Therefore, we can say that switch sends the message directly from source to the destination.

Cables and connectors: 
Cable is a transmission media that transmits the communication signals. There are three types of cables: 

• Twisted pair cable: It is a high-speed cable that transmits the data over 1Gbps or more. 
• Coaxial cable: Coaxial cable resembles like a TV installation cable. Coaxial cable is more expensive than twisted pair cable, but it provides the high data transmission speed. 
• Fibre optic cable: Fibre optic cable is a high-speed cable that transmits the data using light beams. It provides high data transmission speed as compared to other cables. It is more expensive as compared to other cables, so it is installed at the government level.

Router:

• A router is a hardware device which is used to connect a LAN with an internet connection. It is used to receive, analyze and forward the incoming packets to another network.
• A router works in a Layer 3 (Network layer) of the OSI Reference model.
• A router forwards the packet based on the information available in the routing table.
• It determines the best path from the available paths for the transmission of the packet.

Modem: 
Modem connects the computer to the internet over the existing telephone line. A modem is not integrated with the computer motherboard. A modem is a separate part on the PC slot found on the motherboard. It stands for Modulator/Demodulator. It converts the digital data into an analog signal over the telephone lines.

Some important Uses Of Computer Network

• Resource sharing: Resource sharing is the sharing of resources such as programs, printers, and data among the users on the network without the requirement of the physical location of the resource and user.
• Server-Client model: Computer networking is used in the server-client model. A server is a central computer used to store the information and maintained by the system administrator. Clients are the machines used to access the information stored in the server remotely. 
• Communication medium: Computer network behaves as a communication medium among the users. For example, a company contains more than one computer has an email system which the employees use for daily communication. 
• E-commerce: Computer network is also important in businesses. We can do the business over the internet. For example, amazon.com is doing their business over the internet, i.e., they are doing their business over the internet.

Computer Network Types

A computer network is a group of computers linked to each other that enables the computer to communicate with another computer and share their resources, data, and applications.
A computer network can be categorized by their size. A computer network is mainly of four types:

• LAN(Local Area Network)
• PAN(Personal Area Network)
• MAN(Metropolitan Area Network)
• WAN(Wide Area Network)

LAN (Local Area Network):

• Local Area Network is a group of computers connected to each other in a small area such as building, office. 
• LAN is used for connecting two or more personal computers through a communication medium such as twisted pair, coaxial cable, etc. 
• It is less costly as it is built with inexpensive hardware such as hubs, network adapters, and ethernet cables. 
• The data is transferred at an extremely faster rate in Local Area Network.

PAN (Personal Area Network):

• Personal Area Network is a network arranged within an individual person, typically within a range of 10 meters.
• Personal Area Network is used for connecting the computer devices of personal use is known as Personal Area Network.
• Thomas Zimmerman was the first research scientist to bring the idea of the Personal Area Network.
• Personal Area Network covers an area of 30 feet.
• Personal computer devices that are used to develop the personal area network are the laptop, mobile phones, media player and play stations.

There are two types of Personal Area Network:

• Wireless Personal Area Network: Wireless Personal Area Network is developed by simply using wireless technologies such as WiFi, Bluetooth. It is a low range network.
• Wired Personal Area Network: Wired Personal Area Network is created by using the USB.

MAN (Metropolitan Area Network):

• A metropolitan area network is a network that covers a larger geographic area by interconnecting a different LAN to form a larger network.
• Government agencies use MAN to connect to the citizens and private industries.

WAN (Wide Area Network):

• A Wide Area Network is a network that extends over a large geographical area such as states or countries.
• A Wide Area Network is quite bigger network than the LAN.
• A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fibre optic cable or satellite links.
• The internet is one of the biggest WAN in the world.
• A Wide Area Network is widely used in the field of Business, government, and education.

Internetwork:

• An internetwork is defined as two or more computer network LANs or WAN or computer network segments are connected using devices, and they are configured by a local addressing scheme. This process is known as internetworking.
• An interconnection between public, private, commercial, industrial, or government computer networks can also be defined as internetworking.
• An internetworking uses the internet protocol.
• The reference model used for internetworking is Open System Interconnection(OSI).

Types of Internetwork:

• Extranet: An extranet is a communication network based on the internet protocol such as Transmission Control protocol and internet protocol.
• Intranet: An intranet is a private network based on the internet protocol such as Transmission Control protocol and internet protocol.