Introduction to Internet
The Internet is made up of millions of computers linked together around the world in such a way that information can be sent from any computer to any other 24 hours a day.
The Internet is a worldwide network of computer networks that connects universities, government, commercial, and other computers around the globe. Internet is simply a network of networks. The diagram below shows a number of possible connections to the Internet. The Internet is typically depicted as a cloud. However, you should see it as the multi-node network diagram from above. In this case, the UCC based ISP, Tanganyika Books Online, Manchester United FC, Google Search Engine, and the Open University of Tanzania are all nodes on the Internet.
Your home PC is connected to your ISP via your telephone line or modem and is not a node on the Internet.
You and others connected to your ISP are part of a star network (with your ISP as the central node) that is connected to the internet.
Connecting to Internet photo Overview
How the Internet Works?
Internet
Internet is a network of networks i.e. a global system comprised of interconnected computers and computer networks, which communicate by means of using TCP/IP protocols. Although in its beginnings, it emerged from the need for simple data exchange, today it affects all domains of society such as economy, socializing, information, healthcare, education, defense, sports, etc.
Intranet
Intranet is a private network of an organization to which only authorized employees to have access (login and password).
Extranet
Extranet is part of Intranet, to which independent collaborators have access.
Internet Data Flow
Data Download and Upload
The download is a term that implies taking a copy of digital data from a network computer on a local computer, and uploading means placing digital content on a network computer.
Bit Rate
Bitrate represents the speed at which data is transferred through a modem (network). It is measured in bit/s (bit per second). The bit/s is a measurement unit for the speed of digital data flow through the network. The number of bits transferred in one second tells us how many bits can be transferred through a network in one second. For example:
- 1,000 bit/s rate = 1 kbit/s (one kilobit or one thousand bits per second)
- 1,000,000 bit/s rate = 1 Mbit/s (one megabit or one million bits per second)
- 1,000,000,000 bit/s rate = 1 Gbit/s (one gigabit or one billion bits per second)
Speed of data flow can be expressed in bytes per second. Since one byte has eight bits, such as the relation between bit/s and Bp/s, i.e. bits per second and bytes per second.
Connecting to the Internet
Several ways can be used to connect your computer to the Internet. Some of them include:
- The dial-up Internet access method uses a modem (56k) and a telephone line.
- Broadband is characterized by a high-speed data transfer, permanent access to the Internet, and thus the risk of unauthorized access to the network or your personal computer. At the beginning of broadband Internet access, due to underdeveloped communication infrastructure, Internet providers charged based on the data traffic but not time spent on the Internet (unlike dial-up Internet access).
Today, in large cities, telecommunications infrastructure is developed, therefore Internet providers do not charge money based on the time spent on the Internet or the amount of transferred data, but they do charge by access speed.
The connection methods include:
- Mobile-connecting by using a mobile network (GPRS, EDGE, UMTS, HSPA).
- Satellite-commonly used in parts of the world where there is no proper infrastructure and there is no other way of accessing the Internet.
- Wireless (Wi-Fi) - data is transferred between computers by using radio frequencies (2,4 GHz) and the corresponding antennas.
- Cable - connecting to the Internet through a television cable network using a cable modem.
Internet Service Providers
An Internet service provider (ISP) is an organization that provides services for accessing the Internet. Some of the Internet services provided by ISPs include Internet access, Internet transit, domain name registration, web hosting, Usenet service, and colocation.
A computer is connected to the Internet through a built-in modem or router for networking, but without a subscription with an ISP, it won't have a connection to the Internet. An ISP is your gateway to the Internet and everything else you can do online. The ISPs can be dial-up services, high-speed Internet (broadband) offered by cable companies, and DSL (Digital Line Subscribers) offered by phone companies. Now, the most current high-speed Internet services depend on the Fiber Internet (fiber optical or broadband). The FiOS (fiber optic services) provides superfast Internet connection speeds. All telecoms (mobile) companies in Tanzania offer Internet services and are considered local ISPs.
Web Browsers
A web browser is a software application for accessing the information on the World Wide Web (WWW). Each individual web page, image, and video is identified by a distinct Universal Resource Locator (URL). A URL is simply a web address. Note that a web browser is not the same thing as a search engine. A search engine is just a website, such as google.com, that stores searchable data about other websites. But in order to connect to and display websites on their device, a user needs to have a web browser installed. The most popular and common web browsers include Internet Explorer from Microsoft, Firefox from Mozilla, Google Chrome, Safari from Apple, Opera, and Edge. All major browsers have mobile versions that are lightweight versions for accessing the web on mobile devices.
Web Browsers Overview
A web browser is a software program that allows a user to locate, access, and display web pages. Browsers display websites and contents created using languages such as Hypertext Markup Language (HTML) and Extensible Markup Language (XML).
Browsers translate web pages and websites delivered using Hypertext Transfer Protocol (HTTP) into human-readable content. They also have the ability to display other protocols and prefixes, such as secure HTTP (HTTPS) and File Transfer Protocol (FTP).
Networking Basics
A network is simply two or more computers linked together so that their files or resources can easily be shared or transferred through electronic communications. A computer network is comprised of at least two, connected, by wire (cables) or wireless to exchange data i.e. communicate. There are many reasons for connecting computers into a network, and some of them are:
-exchange of data between users that have network access,
-access to shared devices, such as network printers, network
disks, etc.,
-enables user communication and socializing, etc.
Internet is the most famous and most widespread network with
over 2 billion users and the number of users is still growing.
Types of Computer Networks
Types of Networks based on Size
A computer network can be structured depending on its size and
geographical coverage. Basically, computer networks are categorized as Local
Area Network (LAN) and Wide Area Network (WAN). Sometimes, a Metropolitan Area
Network (MAN), also called Wireless Local Area Network (WLAN) is considered as
a type of computer network.
The simplest network is the LAN. The LAN computers are in the same office or building. Rarely are LAN computers one mile apart. LAN network covers a relatively small geographical area and it connects computers within a firm or household by wire.
LAN Infrastructure
A WAN network that covers a relatively large geographical
area and it connects a greater number of computers and local networks. When
computers in different buildings or cities are connected together, the network
is called a WAN. A WAN comprises individual computers and LANs. A typical
example of a Wide Area Network is the Internet.
Types of Networks based on Architecture
Types of networks according to their architecture include a client-server and peer-to-peer (P2P). In a client-server architecture, all clients are connected to the server while in a peer-to-peer; all computers are clients and servers at the same time. In a client-server relationship, a client computer sends requests and the server responds to those requests. We can use the Internet as the best-known example of client-server architecture.
The user's computer, connected to the Internet, sends requests to a certain web page (by entering the page address (URL) into the Internet browser address bar), and the server responds. Web page is loaded into the user's computer Internet browser as a result of server response. From this example, we can see that communication between client and server depends on connection speed (bandwidth). Since bandwidth is limited, the amount of data that can flow through the network is limited too.