Basic Internet Terminology, Types Of Internet Connections, Uses And Hazards Of Internet
Basic Internet Terminology
Web page is the basic unit of information available on the Web. The World Wide Web consists of files, known as pages or web pages, containing information and links to resources throughout the Internet. A website is a set of intimately connected web pages which are inter-linked by logical pointers called hyperlinks. Generally, a single page is designed as the website’s home page. This home page is the entry point comprising of a content list or index for people to view the request information on this website and may also provide leads to other websites containing again a set of web pages that holds the desired subject matter.
A Web browser or, in short, a browser is an application program that makes the content on the Internet viewable. It interprets the HTML code embedded within the Web page and converts the data of the Internet in the graphical interface that one sees on a website and displays and plays all elements such as images, sounds, motion, and other features of a website at their designated positions. Web browsers provide the way to send request for a web page by specifying its internet address that is processed by the corresponding web server. The Web server residing at remote computer sends the desired web page to the browser.
There are two types of browsers—graphical and text.
Graphical browser Text, images, audio, and video are retrievable through a graphical software program such as Internet Explorer, Firefox, Netscape, Mozilla, and Opera. These browsers are available for Windows, Apple, Linux, and other operating systems. Pointing and clicking with a mouse on highlighted words and graphics accomplish navigation. Text browser It is a browser that provides access to the web only in the text mode. Navigation is accomplished by highlighting emphasized words in the screen with the arrow up and down keys, and then pressing the forward arrow (or Enter) key to follow the link. One example of such a browser is the Lynx text mode browser. In this era of graphical browsers, it may be hard to believe that Lynx was once very popular.
A Web server is an application program that runs on the host computer and manages the web pages stored on the website’s repository. Its purpose is to provide the information and services to the Web users. Typically, users can request an initial web page, known as home page, from the Web server through the browser that displays the page. Once the home page is displayed, the user can begin surfing the Web. The process of looking at different things on the Internet is known as surfing. Whenever the mouse pointer is clicked on a hyperlink, a page request is sent by it through the browser, at the client end, to the Web server of the desired page. In return, the Web server sends a copy of the requested page to the client’s browser. The browser, at the client end, receives the page and then displays it.
Internet Service Provider
An Internet Service Provider (ISP) is an establishment that offers Internet access against monthly or annual subscription to its customers who might be an individual, organizations, or smaller ISPs. Some of the major ISPs in India are NICNet, VSNL, Satyam, and so on.
A network node that works as an entrance to some other network is called a gateway. A node or a stopping junction, in the Internet jargon, may be a host node or a gateway node. The host node is an end point node. The computers that serve the pages on the Internet on request and the Internet users computers are termed as host nodes.
On the other hand, the gateway nodes are computers that regulate the information traffic within an organization’s network or an Internet Service Provider’s (ISP) network. Generally, Transmission Control Protocol/Internet Protocol (TCP/IP) is used by the Internet to transfer information. To identify individual nodes on the Internet and also on LANs, a low-level protocol, called IP, is used. At a given time, each node on the Internet is assigned a number which is called the IP address. Since it is difficult for the user to remember an IP address, each node is allotted a domain name using which a corresponding IP address can be obtained. In the current scenario, instead of assigning permanent IP address to a user, the moment the user’s computer gets connected to the Internet, the computer at the user’s ISP allocates a temporary IP address from a range of addresses assigned to that ISP. These are known as dynamic IPs.
On the other-hand, TCP works at a different level over the IP and provides features like message tracking, error checking, and retransmitting. Since IP does not have any error checking feature, TCP is used alongside IP to provide reliable transmission from sender to receiver.
URL is the abbreviation of Uniform Resource Locator. It provides a uniform way of identifying resources that are available at host computer (The computer on which a website is physically located). It specifies the Internet address of a file stored on the host computer connected to the Internet. Web browsers use the URL to retrieve a file from host computer. The simplest format for a URL is as follows. protocol://host/path/filename where Protocol Protocol is a mutually agreed set of rules or methods for transmitting data between two devices. Here the term ‘protocol’ means the HTTP, which designates the Web’s standard communications protocol through which a client establishes a TCP connection to the host server for the resource to be accessed. The double slash (// ) indicates that the protocol uses the format defined by the Common Internet Scheme Syntax (CISS).
Apart from http, other protocols available include ftp, gopher, and mailto. Host It specifies a particular host on the Internet by a unique numeric identifier, known as an IP address or by a unique name that can be resolved into the IP address. The domain is a set of nodes that are administered as a unit. The domain name is the hierarchical name assigned to a host address using the Domain Name System (DNS). A domain name consists of two to four words separated by dots.
Starting from the right is a top-level domain name, such as com for commercial. The top-level domain names are assigned by the Internet Corporation for Assigned Names and Numbers (ICANN). An organization’s domain name is assigned to a host computer that is linked to the Internet. Every domain name has a suffix that indicates the purpose for which it is used. The most widespread domain suffix is ‘.com’ and even though it stands for commercial, it is used by many non-commercial websites as well. Also, every country has a specific suffix.
A few examples are as follows .com—this identifies a business enterprise (commercial) .us—this is intended for use by US websites .de—this is intended for use by German websites .org—this identifies an organization .edu—this identifies an educational organization .gov—this identifies a government agency Path This is the location of a file or a program (JSP, PHP, Perl, CGI, etc.) on the server relative to a document root specified by the Web server. The document root is a directory where resources are stored. Figure 6.2 provides a suitable explanation for the URL.
For physical transmission of a message to the destination node, its physical Media Access Control (MAC) address is required. MAC address is a unique built-in number that permanently identifies a network adapter of a computer. The Address Resolution Protocol (ARP) translates the IP address to a MAC address. The message is then routed to the destination computer. Internet address translation is depicted in Fig. 6.3.
Search engines are application programs that allow searching the Web by typing in a topic of interest. Examples of search engines used are—Google, HotBot, Altavista, etc. These search engines find exact matches from what has been typed in the search screen to either documents (files) or subjects of files on the www. Different search engines have different ways of categorizing and indexing information. Typing in the URL of that engine or using a browser’s compilation of search engines in its Internet search function accesses search engines.
Types of Internet Connections
The most general type of Internet connections, available from ISPs, are the dial-up connections that use a telephone line to transmit and receive data. It blocks the telephone line and is the slowest and the most inexpensive among the different types of available Internet connections. This type of connection permits the user to connect to the Internet through a local server using an analog modem and the Public Switched Telephone Network. To get connected to the Internet, the PC literally dials a phone number, provided by the ISP and connects to the local server. The maximum data rate with dial-up access is 56 Kbps (56,000 bits per second), but technologies such as Integrated Services Digital Network (ISDN), which uses the Public Switched Telephone Network, provide faster data rates of 128 Kbps.
An alternative way to connect computers to the Internet is through a leased line, which is a dedicated wire or an optical fibre cable or a wireless channel that directly connects them to the Internet using Public Switched Telephone Network. Leased lines provide faster throughput and better quality connections, but they are more expensive. These are mostly used by large business houses and big establishments.
Another old technology, known as the T-carrier lines, is also available as leased lines. Under this category the fractional T1/T3 lines provide data rates between 56 and 1,500 kbit/s. Some types of special termination equipment are necessary for such lines. These are installed in some multi-resident dwellings, fractional. T1/T3 lines are typically underground fibre or copper cables that connect directly to the service provider, with individual home connections switched over Ethernet cables.
Digital Subscriber Line (DSL)
This is a connection using a phone line and a special modem. The modem does not interfere with the normal telephone operation. Most connections average about 400–650K per second in download (some are faster), while some average about 128–256K per second upload speed as well.
A satellite Internet connection is a system in which a computer receives(downloads) and sends(uploads) data streams through a satellite. In such a connection, every user computer is provided with a transmitter-receiver unit and a satellite dish antenna. The upstream data transfer rate is much less than the down-stream rate in these systems. In areas where DSL or any other type of wire internet connections are difficult to reach, the satellite internet connection is the only option for accessing the Internet. For people in the rural areas and those living on hilly areas or in places where the basic utilities are lacking satellite Internet connection is an effective means of availing the Internet. However such systems are expensive and are slower than the land-based systems.
Broadband Versus Power Line
Broadband over Power Line (BPL) supports Internet connections over residential power lines. The technology behind power line BPL works analogous to phone line DSL, using unused signalling space on the wire to transmit the Internet traffic. BPL requires specialized (but not expensive) equipment to connect to a home network.
Cable Modem Broadband
Cable modem broadband is a connection through an ordinary coax cable through the user’s digital cable provider and is the easiest and most common way to connect to the Internet at high speeds. Most connections average about 400K/second download and 128K upload. A cable’s biggest advantage is its availability and ability to produce multiple upstream (when sending). Cable connections are always on; eliminating long waits to make a connection. Cable connections are not available in every area; the users will need to contact a cable company of their choice to ensure that they have coverage.
Other forms of Internet Connectivity
Cellular Internet Mobile Internet connections can be made over digital cell phones. Due to high costs, cellular Internet is usually used in homes only during emergencies.
Wireless Broadband Internet WiMax technology supports high-speed wireless Internet via base stations such as cellular networks. The WiFi community or ‘mesh’ networks serve a similar function using different technologies.
Uses of Internet
One of the most outstanding innovations in the field of communication is the Internet. As with every single innovation, the Internet has its own advantages and disadvantages. However, its many advantages outweigh its disadvantages.
Communication has always been the primary target of the Internet. However, continuous innovations are making it faster and more reliable. With the advent of the Internet, the earth has been transformed into a global village. Some of advantages are as follows. E-mail Electronic mail or e-mail is an online correspondence system. It allows computer users to exchange messages locally and across the world. Each user of e-mail has a mailbox address to which messages are sent. Messages sent through e-mail arrive instantly. The e-mail system is based on the Simple Mail Transfer Protocol (SMTP). Multimedia Internet Mail Extension (MIME) was originally developed to help e-mail software handle a variety of binary (non-ASCII) file attachments.
The use of MIME has expanded to the Web. Chat and Instant messaging Chat programs allow users to communicate with each other through the Internet by typing in real time. Sometimes, they are included as a feature of a website, where users can log into chat rooms to exchange remarks and information about the topics addressed on the site. Chat may take many other wide-ranging forms.
For example, America Online is well-known for sponsoring a number of topical chat rooms. Internet Relay Chat (IRC) is a service through which participants can communicate with each other on hundreds of channels. The discussions on these channels are generally based on specific topics. To access IRC, a user must use an IRC software program. A variation of chat is the phenomenon of instant messaging. With instant messaging, a user on the Web can contact another logged- in user and start a conversation. One of the most popular Internet relay chat sites is America Online’s (AOL) instant messenger. ICQ, MSN, and Yahoo also offer chat programs.
Telnet It is a program which assists the user to get connected with computers on the Internet and access chat services, library catalogues, online databases, etc. However, Telnet sessions use graphics and not text. To get connected on to a computer using Telnet, the user must know its address. This can consist of words (judde.ac.in) or numbers (.18.104.22.168). Some services require the specification of a specific port on the remote computer. In such a case, the user has to type the port number after the Internet address. A link to a Telnet resource may appear like any other link, but it will launch a Telnet session to provide the connection. In order to work, a Telnet program must be installed on the user’s local computer and configured to his or her Web browser. With the popularity of the Web, Telnet is less frequently used as a means of access to information on the Internet.
The biggest advantage the Internet offers is probably information. It is a virtual treasure trove of information. Any kind of information on any topic is available on the Internet. Search engines such as Google, Yahoo!, and others help in retrieving information from the Internet. People can get almost any type of data on almost any kind of subject that they are looking for. There is a massive amount of information available on the Internet on just about every subject known to man—ranging from government law and services, market information, technical support, new ideas, trade fairs and conferences, etc. Usenet news is a collection of news groups that have nothing to do with news. Usenets are ongoing discussion groups on the Internet, among people who share mutual interest. Usenet News is a global electronic bulletin board system in which millions of computer users exchange information on a vast range of topics.
The major difference between Usenet News and e-mail discussion groups is the fact that Usenet messages are stored on central computers, and users must connect with these computers to read or download the messages posted to these groups. This is distinct from email distribution, in which messages arrive in the electronic mailboxes of each listed member. Usenet itself is a set of machines that exchange messages or articles from Usenet discussion forums, known as newsgroups. Usenet administrators control their own sites, and decide which (if any) newsgroups to sponsor and which remote newsgroups to allow into the system. Web blog or simply blog is a new form of online update- able diary that can be created with the help of the Internet.
Many people, groups of people, and organizations post their information or knowledge or their views, etc. to share. It has organizational and personal roles. Blogger provides one of the most popular and oldest web blog services which have been owned by google since 2003. Students and children are among the major users who surf the Internet for research purposes. Today, it is essential for students to access the Internet for research and for gathering resources. Teachers give assignments that require research on the Internet. Due to the Internet, it has now become possible to locate information on ever-changing fields such as medical research. Numerous websites available on the Internet offer loads of information for people to research about diseases and discuss health issues with online doctors. During 1998, over 20 million people were reported to have used online resources to retrieve information about health issues.
Many people prefer to surf the Internet in search of entertainment. In fact, the Internet has become quite successful in providing multifaceted entertainment options. Some of the uses people have discovered are—downloading games, visiting chat rooms, or just surfing the Web. There are lots of games that may be downloaded from the Internet for free. The online gaming industry has tasted dramatic success due to the phenomenal interest shown by game lovers. Chat rooms are popular because users can meet new and interesting people. News, music, hobbies, and many more areas of interest can be found and shared on the Internet. Apart from these, there are plenty of messenger services to facilitate this. With the help of such services, it has become very easy to establish global friendship where people can share their thoughts. Social networking websites such as Facebook, and MySpace extend the new form of interactions that outspreads socialization.
Many services are now provided on the Internet such as job seeking, guidance services on a variety of topics, online banking, online share trading, purchasing tickets for movies, and hotel reservations. Some of these services may not be available off-line and can cost less if purchased online.
The concept of any type of commercial activity or business deal that involves the transfer of information across the globe through the Internet is known as e-commerce. It has become a phenomenon that is associated with any type of online business transaction. E-commerce, with its giant tentacles engulfing every single product and service, will make almost all services and products available at one’s doorstep. It covers an amazing and wide range of products from household needs to technology and entertainment.
Hazards of Internet
Despite the numerous advantages of the Internet, it also endures the security and protection hazards, some of which are discussed as follows:
• Virus is a piece of code which on execution disrupts the normal functioning of computer systems. Computers attached to the Internet are more susceptible to virus attacks which can end up with mischievous behaviour or crashing the system.
• Hackers utilize one type of virus called Trojans to gain access to the computer to intercept personal or secret information (such as password, credit card number) there by invading users’ privacy, or use the intended victim’s computer for their purposes.
• Spamming refers to sending unsolicited bulk e-mails, which provide no purpose and needlessly obstruct the entire system.
Such illegal activities can be very frustrating for the users, and so instead of just ignoring them, they should make an effort to try and stop these activities so that using the Internet can become much safer. Internet addiction is another important menace to the society. the Internet has established its potential for encompassing new forms of social interactions and leisure activities. Websites like Facebook, Orkut, and Myspace have shaped socialization in such a dimension that people especially students get addicted to surfing the Internet. Pornography There are thousands of pornographic sites on the Internet that can be easily accessed; hence, children should use the Internet with parental supervision.
Frequently Asked Questions
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- Introduction - What Is A Computer
- Evolution Of The Computer- A Brief History
- Generations Of Computers
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