Computer Network tutorial provides basic and advanced concepts of Data Communication & Networks (DCN). Our Computer Networking Tutorial is designed for beginners and professionals.

Our Computer Network tutorial includes all topics of Computer Network such as introduction, features, types of computer network, architecture, hardware, software, internet, intranet, website, LAN, WAN, etc

COMPUTER NETWORK

Evolution of Networking:

(a) ARPANET: In 1969, US govt. formed an agency named ARPANET (Advanced Research Projects Agency Network) to connect computers at various universities and defense agencies.

(b) Internet (INTER-connection NETwork): The Internet is a worldwide network of computer networks.

Switching Techniques: are used to transmit data across networks.

(a) Circuit switching complete the data are transmitted.

physical connection between two computers is established and then repeated until the link send data to another switching office which again does the same. the process is message reaches the destination.

(b) Message Switching: here the source sends data or message into the switching office which looks for a free

(c) Packet Switching: similar to message switching except that there is strict upper limit to the packet size

Data communication Terminologies the data.

(a) Channel: it is medium that carries Transmission Media of a transmission channel.

(b) Band: It is a measure of the data carrying capacity of a channel.

(c) Band width it is the difference between the highest and lowest frequencies

(d) Data Transfer Rate: it is the speed with which data is transferred

(a) Twisted Pair Cable: It consists of two identical 1mm thick copper wires insulated and twisted together

Advantages:

(i) It is easy to install and maintaining

(ii) It is inexpensive.

(iii) It is incapable to carry a signal over long distances without the use of repeaters.

Disadvantages:

(ii) Due to low band width, these are unsuitable for broadband applications.

(b) Coaxial Cables: It consists of a solid wire core surrounded by one or more foil or braided wire shields.

Advantages:

(i) Data transmission rate is better than twisted pair cables.

(ii) It is inexpensive.

Disadvantages:

(1) Expensive than twisted pair cables.

(ii) Difficult to manage and reconfigure.

(c) Optical fiber: It consists of thin glass fibres that can carry information in the form of visible light

Advantages:

(iv) Bandwidth is up to 10 Gbps.

Disadvantages:

(1) Expensive as compared to other guided media.

(ii)Need special care while installation.

(d) Infrared: The infrared light transmits data through the air and can propagate throughout a room

Advantages:

(i) Power consumption is used.

(ii)Circuitry cost is less Secure mode transmission.

Disadvantages:

(1) Transmit data over long distance with high security.

(ii) Data transmission speed is high.

(iii) Provide better noise immunity.

Limited in a short range. Can be blocked by common materials like walls, people, plants, etc...

(e) Radio wave: It is an electromagnetic wave with a wavelength between (0.5) cm and 30,000 m.

Advantages:

Radio wave transmission offers mobility

(i) It is cheaper than laying cables and fibers (ii) It offers ease of communication over difficult terrain. STRAND

Disadvantages:

Radio wave communication is insecure communication.

Radio wave propagation is susceptible to weather effects like rains, thunder storms, etc.

(1) Microwave The microwave transmission is a line of sight transmission. radiowaves of more tha 3ghz frequency are known as microwaves.

Advantages:

It is cheaper than laying cable or fiber.

(ii) It has the ability to communicate over oceans.

(i) Microwave propagation is susceptible to weather effects like rains, thunder storms, etc. Satellite link: The satellite transmission is also a kind of line of sight transmission that is used to trail signals throughout the world. It is a microwave relay system.

Disadvantages:

Microwave communication is an insecure.communication...

Advantages:

(ii) No line of sight restrictions such as natural mountains, tall buildings, towers, etc.

(iii) Earth station which receives the signals can be fixed position or relatively mobile.

Disadvantages:

(1) Area covered is quite large.

(2) Very expensive as compared to other transmission mediumInstallation is extremely complex

(3) Signals sent to the stations can be tampered by external interference.

Network Devices

These are units that mediate data in a computer network and also called network equipments.

(a) Modem: It facilitates communication between computers over telephone line's

(b) RJ45 Connector: it is used to connect computers on the local area network

(c) Ethernet card: It is used to support a special LAN architecture called Ethernet that uses bus or star topology and supports data transfer rate of upto 10 Mbps

(d) Hub: It is used to connect several computers together

(e) Switch: It is used to divide a network into sub networks to prevent traffic over loading

(f) Gateway It connects two dissimilar networks.

(g) Repeater it amplifies the signal being transmitted over a networking

Network Topologies:

the way nodes of a network are interconnected is called network topology.

(a) Bus Topology: It uses a common single cable to connect all the workstations

(b) Star Topology: It is based on a central which acts as a hub.

(c) Tree Topology: It combines the characteristics of the linear bus and star topologies.

Network Types:

(a) LAN(Local Area Network): It is a network that is confined to a relatively small area.

(b) MAN (Metropolitan Area Network): It is a network that covers a group of nearby corporate offices in a city

(c) WAN (Wide Area Network): These are the networks spread over large distances, say across countries or ev continents through cabling or satellite uplinks

(d) PAN(Personal Area Network): It is a computer network organized around an individual person.

Network Protocol:

It is a set of rules that define how two systems communicate.

(a) Hypertext Transfer Protocol (HTTP) it defines the transfer of hypertext, graphic, image, saundarya messages,etc on WWW

(b) FTP (File Transfer Protocol): defines transfer of files across internet

(d) SMTP Simple Mail Transfer Protocol) it is used for fetching mails from the remote server. (e) POP3 (Post Office Protocol Version3); it is used for spending messages.

TERMS RELATED TO INTERNET

www is a set of protocols that allows the acces of any document on the net.

>HTML: It is a document layout and hyperlink specification language.

XML: It is a markup language for documents containing structured information. > URL: It is Uniform Resource Locator, which is a special address for resources on the internet.

Domain Names: A character based internet address is known as a Domain name. Website: web site is a collection of web pages that are linked together.

> Web Address: Every web site has a unique address called the web address

> Web server. It is a WWW server that responds to the requests made by the web browser

>Web Browser: A web browser is a WWW client that navigates through the world wide web and displays web pages.

> WEB Hosting: It is a means of hosting web-server application on a computer through which electronic content on

the internet is readily available to any to any web-browser client.c.

Mr indian coder

Wednesday, 25 January 2023