Internet

Electronic Mail (email)

• People use email for sharing infromation data files, photos, videos, business communications and more. This has enabled faster communication between people and improved business efficiency. An email has reduced paper usage and the load of physical mail systems.

FTP File Transfer

• FTP is the file transfer protocol that enables data exchanges between two stakeholders over internet media in a secure way.
• The data exchange may occur between two business entities or customers with business and vice versa.
• Usually, email restricts the size of a file that can be shared, and it is not secure to share sensitive and confidential data accross public Networks. FTP concept is still is use in mobile apps for file downloading.

Search Engines

• These engines locate the information one seeks, available on whichever server accross the globe (world wide web).
• One can search for anything on this site, and the search question can be in any format.

E-Commerce

• The internet enables the selling of goods and services in online mode.
• Many e-commerce platform vendors like Amazon and Ola aggregate several products/services available in market and sell them through their portal to customers.
• Products are procured by platform vendors, stored in their warehouses, packed and distributed by them in their brand. Customers get a good discount and don't have to visit physical stores.

Online Banking

• Called Net banking, it allows doing banking transactions at ease sitting at home or while on mobile.
• Any amount of money can be transferred instantaneously through this facility.
• E-Banking supports electricity bills, telephone bills and other services payments.

Education

• The internet offers a wealth of educational material on any subject with structured navigation and search facilities.
• One can seek any reading material, and the internet will get it for them from any server in any part of the world, and people need not have to go to libraries to go through books.

Social Networking

• Internet connects people online and enables them to form social groups.
• Information, ideas, views and opinions on social/political issues are exchanged.
• Political and social organization uses this platform to promote their interest among the public.

Connectivity, communication and sharing

• One can send a letter or important information to anyone in the e-mail all over the world through the internet. And, it often will be delivered to the destination in less than a minute.

Information, knowledge and learning

• The internet allows people to learn information about any topic and offers an answer to any type of question, as it contains endless knowledge and information.
• Using search engine like Google Chrome, Mozilla Firefox, and more they all allow users to ask any question and find a web page with an answer about that question.

Address, mapping and contact information

• The internet can help users to provide information almost every place in the world on the map with the help of GPS technology.
• You can find businesses in your area or the quickest route to your location.

Selling and making money

• If you want to sell products and services or run a business, the internet is the best place to sell goods. Because anyone can find and access your website all over the world with the help of internet.
• With online business, you are able to sell goods every day at all times as the internet is always on and always available.
• Also, the internet provides the advantage to promote your business online in the world through advertising. Additionally, there are several ways to make money online by performing other online services.

Banking, bills and shopping

• If you want to view your bank balance without leaving your home, the internet offers you the benefit to access your bank account to view the balance. Also you can send money, pay bills through internet.
• Other advantage of internet is online shopping, which allows people to find products of interest and buy them without having to visit a store.
• You can compare prices between companies for any product through the internet. Also, you can get help to make better purchasing decisions by online reviews, which describes what others thing about a product.

Donations and funding

• with the help of an internet connection, anyone can help fund projects and ideas that interest them or quickly donate to their favorite charity.
• Also, if you want to donate and looking for charity services, you can find many online services on the Internet that help make it easier to support their causes or help donate.

Entertainment

• The internet provides people to access endless entertainment. With the internet, you can watch movies, videos, play games online, listen to music, etc.
• There are many sites available on the internet, which contain different entertainment material like music, videos and more.
• Also, you can watch onine videos on a platform like Youtube.
• Futhermore, you can download any movies, videos or other entertainment material via the internet on devices like computers or mobile phones that can be played anytime without an internet connection.

Work from home

• The internet offers people benefit to connect with others around the world.
• There are various online services that help you to communicate and work with other people all over the world.
• Also, it can make services and producing new products faster.

Cloud storage

• One of the biggest advantages of the internet offers connectivity to your computer and internet enabled devices to connect with cloud services in which we store our data.

LAN (Local Area Network)

• Group of interconnected computers within a small area. (room, building, campus).
• Two or more pc's can form a LAN to share files, folders, printers, applications and other devices.
• Coaxial or CAT 5 cables are normally used for connections.
• Due to short distances, errors and noise are minimum.
• Data transfer rate is 10 to 100 mbps.
• Example → A computer lab in a school.

MAN (Metropolitan Area Network)

• Design to extend over a large area.
• Connecting number of LAN's to form larger network, so that resources can be shared.
• Networks can be up to 5 to 50 Km.
• Owned by organization or individual.
• Data transfer rate is low compare to LAN.
• Example → Organization with different branches located in the city.

WAN (Wide Area Network)

• These are country and worldwide networks.
• Contains multiple LAN's and MAN's.
• Distinguished in terms of geographical range.
• Uses satellites and microwave relays.
• Data transfer rate depends upon the ISP provider and varies over the location.
• Example → internet.

Other Types

• WLAN (Wireless LAN)
  • A LAN that uses high frequency radio waves for communication.
  • Provides short range connectivity with high speed data transmission.
• PAN (Personal Area Network)
  • Network organized by the individual user for its personal use.
• SAN (Storage Area Network)
  • Connects servers to data storage devices via fiber-optic cables.
  • E.g.: Used for daily backup of organization or a mirror copy

Dial-up

• It is a broadband connection that uses a modem to establish data connections over the public switched telephone network (PSTN).
• Dial-up modems are slower than high-speed modems and are often limited in the connection speeds they support.

Leased Line

• A leased line is a high-speed internet connection between two locations.
• The service involves renting a deciated cable to connect two offices or branches together, enabling users to transfer large volumes of data and giving an consistent connection to the internet.
• A single channel leased line offers speeds of up to 10Mb/s, while a double channel leased line can provide up to 40Mb/s.

Cable

• A cable is a collection of wires twisted together to provide a path for electrical signals.
• The twists reduce signal interference that might otherwise occur due to electromagnetic or other source.
• The twists also accomodate the higher frequencies used in fast data-transfer applications.

Fibre-Optics

• Fibre-Optics cables use light waves to carry data from one place to another.
• Fiber-optics cables work by transmitting light waves through glass threads that are thinner than human hair. Because of this, fiber cables have better efficiency than copper wires.

Wireless or Wi-Fi

• It is a way of connecting different devices to a network. In other words, Wi-Fi allows devices to connect to the internet wirelessly.
• Wi-Fi is short for Wireless Fidelity. It is a technology that uses radio waves instead of wires to have an internet connection.

Broadband

• Broadband is a brand name for high-speed internet access, and internet services provided by telecom companies.
• The term broadband is used to differentiate these services from traditional dial-up connections.
• The suffix "broad" refers to the wide bandwidth of the medium being used to transmit the data.

Satellite

• A satellite network is a communication network that uses the satellite system rather than cables.
• the satellite network is used in a situation where the cable network is not possible and can handle the high traffic volume.
• The satellite network is more expensive than the cable network because it uses the satellites in orbit to send data and the satellite is not owned by the company.
• The satellite consists of a satellite dish, a receiver and a transmitter to communicate with the satellite.

Router

• Router is a particular type of device used to connect two or more subnets that cannot be similar.
• It serves two primary functions: managing traffic between these networks by forwarding data packets to their intended IP addresses, and allowing multiple devices to use the same internet connection.
• There are several types of routers, but most routers pass data between LANs (local area networks) and WANs (wide area networks). A LAN is a group of connected devices restricted to a specific geographic area. A LAN usually requires a single router.

Hub

• A hub is a networking device that is used to connect multiple devices or segment on a local network.
• It is physical layer (layer-1) device that simply broadcasts all incoming data to all other output ports, means if a hub has eight ports, then any input data that irrives on port 1 will be transmitted on all ports 2 to 8.
• Hub works like an electric wire, it receives data signals from one device and forwards them to all other ports, except the source port.
• It does not have any capability to identify any frames to know where it should forward because it does not maintain any kind of table like switch. So there is a lot of traffic on the network and network performance is also very poor, only one device transmits information at a particular time.

Bridge

• A bridge is a device used to connect multiple LANs together with a larger Local Area Network (LAN). The network aggregation is known as bridging.
• The bridge is a physical or hardware device but operates at the OSI model's data link layer and is also known as a layer of two switches.
• It is used to divide a network connections into sections, now each section has separate bandwidth. and it is used to improve network performance.

Gateway

• A gateway is a network node that forms a passage between two networks operating with different transmission protocols.
• Depending upon the functionality, a gateway can operate at any of the seven layers of OSI model however it operates on network layer most commonly.

Switches

• Switches are networking devices operating at layer 2 or a data link layer of the OSI model.
• They connect devices in a network and use packet switching to send, receive or forward data packets or data frames over the network.
• A switch has many ports, to which computers are plugged in. When a data frame arrives at any port of a network switch, it examines the destination address, performs necessary checks and sends the frame to the corresponding devices.

Repeaters

• Repeaters are network devices operating at physical layer of the OSI model that amplify or regenerate and incoming signal before retransmitting it.
• They are used in networks to expand its coverage area. They are also known as signal boosters.

Modem

• Modem stands for Modulator and Demodulator.
• It is a device that modulates signals to encode digital information for transmission and demodulates signals to decodes the transmitted information.
• A modem transmits data in bits per second (bps).
• Is is necessary because it acts as translator between the devices and rapidly transmits the information.
• It converts the digital signal to Analog and vice versa to communicate between devices.

Physical Layer

• Deals with all aspects of physically moving data from one computer to the next
• Converts data from the upper layers into 1s and 0s for transmission over media
• Defines how data is encoded onto the media to transmit the data
• Device example: Hub
• Used to transmit data

Data link Layer

• Is responsible for moving frames from node to node or computer to computer
• Can move frames from one adjacent computer to another, cannot move frames across routers
• Encapsulation = frame
• Requires MAC address or physical address
• Protocols defined include Ethernet Protocol and Point-to-Point Protocol (PPP)
• Device example: Switch

Network Layer

• Responsible for moving packets (data) from one end of the network to the other, called end-to-end communications.
• Requires logical addresses such as IP addresses
• Device example: Router
  • Routing is the ability of various network devices and their related software to move data packets from source to destination

Transport Layer

• Takes data from higher levels of OSI Model and breaks it into segments that can be sent to lower-level layers for data transmission
• Conversely, reassembles data segments into data that higher-level protocols and applications can use
• Also puts segments in correct order (called sequencing ) so they can be reassembled in correct order at destination
• Concerned with the reliability of the transport of sent data
• May use a connection-oriented protocol such as TCP to ensure destination received segments
• May use a connectionless protocol such as UDP to send segments without assurance of delivery
• Uses port addressing

Session Layer

• Responsible for managing the dialog between networked devices
• Establishes, manages, and terminates connections
• Provides procedures for establishing checkpoints, adjournment, termination, and restart or recovery procedures

Presentation Layer

• Concerned with how data is presented to the network
• Handles three primary tasks: -Translation, -Compression, -Encryption
• Translation → Changes data so another type of computer can understand it
• Compression → Makes data smaller to send more data in same amount of time.
• Encryption → Encodes data to protect from interception

Application Layer

• Contains all services or protocols needed by application software or operating system to communicate on the network.
• Examples → Firefox web browser uses HTTP

HTTP or HTTPS

• This stands for Hypertext Transfer Protocol or Hypertext Transfer Protocol (secure).
• The secure version is encrypted, meaning that we will encrypt all the data as we send it from the client to the server.
• Now client and server here become very important with application layer protocol. Nearly all application layer protocols use this model, using one device on the client's network and the other on the server.
• Now when we are using HTTP or HTTPS or tranferring a file. Transferring a file in the format of the hypertext. Hypertext is readable by a web browser.

FTP (File Transfer Protocol)

• The FTP allows us to transfer files from a client to a server or from a server to a client.
• We can do it in both directions here.
• FTP typically require a username and password to transfer these files.

TCP/IP

• TCP/IP stands for Transmission Control Protocol/Internet Protocol. The term is used to describe a set of protocols that govern how data moves through a network.
• After the creation of ARPANET, more networks of computers began to join the network, and the need arose for an agreed set of rules for handling data.