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The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private and public, academic, business, and government networks of local to global scope that are linked by a broad array of electronic and optical networking technologies. The Internet carries a vast array of information resources and services, most notably the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support electronic mail.
Most traditional communications media, such as telephone and television services, are reshaped or redefined using the technologies of the Internet, giving rise to services such as Voice over Internet Protocol (VoIP) and IPTV. Newspaper publishing has been reshaped into Web sites, blogging, and web feeds. The Internet has enabled or accelerated the creation of new forms of human interactions through instant messaging, Internet forums, and social networking sites.
The origins of the Internet reach back to the 1960s when the United States funded research projects of its military agencies to build robust, fault-tolerant and distributed computer networks. This research and a period of civilian funding of a new U.S. backbone by the National Science Foundation spawned worldwide participation in the development of new networking technologies and led to the commercialization of an international network in the mid 1990s, and resulted in the following popularization of countless applications in virtually every aspect of modern human life. As of 2009, an estimated quarter of Earth's population uses the services of the Internet.
The Internet has no centralized governance in either technological implementation or policies for access and usage; each constituent network sets its own standards. Only the overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address space and the Domain Name System, are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN). The technical underpinning and standardization of the core protocols (IPv4 and IPv6) is an activity of the Internet Engineering Task Force (IETF), a non-profit organization of loosely-affiliated international participants that anyone may associate with by contributing technical expertise.
The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet is a global data communications system. It is a hardware and software infrastructure that provides connectivity between computers. In contrast, the Web is one of the services communicated via the Internet. It is a collection of interconnected documents and other resources, linked by hyperlinks and URLs. The term the Internet, when referring to the Internet, has traditionally been treated as a proper noun and written with an initial capital letter. There is a trend to regard it as a generic term or common noun and thus write it as "the internet", without the capital.
The complex communications infrastructure of the Internet consists of its hardware components and a system of software layers that control various aspects of the architecture. While the hardware can often be used to support other software systems, it is the design and the rigorous standardization process of the software architecture that characterizes the Internet and provides the foundation for its scalability and success. The responsibility for the architectural design of the Internet software systems has been delegated to the Internet Engineering Task Force (IETF). The IETF conducts standard-setting work groups, open to any individual, about the various aspects of Internet architecture. Resulting discussions and final standards are published in a series of publications, called Request for Comments (RFCs), freely available on the IETF web site. The principal methods of networking that enable the Internet are contained in specially designated RFCs that constitute the Internet Standards.
These standards describe a framework known as the Internet Protocol Suite. This is a model architecture that divides methods into a layered system of protocols (RFC 1122, RFC 1123). The layers correspond to the environment or scope in which their services operate. At the top is the Application Layer, the space for the application-specific networking methods used in software applications, e.g., a web browser program. Below this top layer, the Transport Layer connects applications on different hosts via the network (e.g., client-server model) with appropriate data exchange methods. Underlying these layers are the core networking technologies, consisting of two layers. The Internet Layer enables computers to identify and locate each other via Internet Protocol (IP) addresses, and allows them to connect to one-another via intermediate (transit) networks. Lastly, at the bottom of the architecture, is a software layer, the Link Layer, that provides connectivity between hosts on the same local network link, such as a local area network (LAN) or a dial-up connection. The model, also known as TCP/IP, is designed to be independent of the underlying hardware which the model therefore does not concern itself with in any detail. Other models have been developed, such as the Open Systems Interconnection (OSI) model, but they are not compatible in the details of description, nor implementation, but many similarities exist and the TCP/IP protocols are usually included in the discussion of OSI networking.
The most prominent component of the Internet model is the Internet Protocol (IP) which provides addressing systems (IP addresses) for computers on the Internet. IP enables internetworking and essentially establishes the Internet itself. IP Version 4 (IPv4) is the initial version used on the first generation of the today's Internet and is still in dominant use. It was designed to address up to ~4.3 billion (109) Internet hosts. However, the explosive growth of the Internet has led to IPv4 address exhaustion which is estimated to enter its final stage in approximately 2011. A new protocol version, IPv6, was developed in the mid 1990s which provides vastly larger addressing capabilities and more efficient routing of Internet traffic. IPv6 is currently in commercial deployment phase around the world and Internet address registries (RIRs) have begun to urge all resource managers to plan rapid adoption and conversion.
IPv6 is not interoperable with IPv4. It essentially establishes a "parallel" version of the Internet not directly accessible with IPv4 software. This means software upgrades or translator facilities are necessary for every networking device that needs to communicate on the IPv6 Internet. Most modern computer operating systems are already converted to operate with both versions of the Internet Protocol. Network infrastructures, however, are still lagging in this development. Aside from the complex physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contracts (e.g., peering agreements), and by technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet is defined by its interconnections and routing policies.
The Internet is a globally distributed network comprising many voluntarily interconnected autonomous networks. It operates without a central governing body. However, to maintain interoperability, all technical and policy aspects of the underlying core infrastructure and the principal name spaces are administered by the Internet Corporation for Assigned Names and Numbers (ICANN), headquartered in Marina del Rey, California. ICANN is the authority that coordinates the assignment of unique identifiers for use on the Internet, including domain names, Internet Protocol (IP) addresses, application port numbers in the transport protocols, and many other parameters. Globally unified name spaces, in which names and numbers are uniquely assigned, are essential for the global reach of the Internet. ICANN is governed by an international board of directors drawn from across the Internet technical, business, academic, and other non-commercial communities. The US government continues to have the primary role in approving changes to the DNS root zone that lies at the heart of the domain name system. ICANN's role in coordinating the assignment of unique identifiers distinguishes it as perhaps the only central coordinating body on the global Internet. On November 16, 2005, the World Summit on the Information Society, held in Tunis, established the Internet Governance Forum (IGF) to discuss Internet-related issues.
Advantages and Disadvantages of Internet
The Internet provides many facilities to the people. The main advantages of Internet are discussed below
1. Sharing Information
You can share information with other people around the world. The scientist or researchers can interact with each other to share knowledge and to get guidance etc. Sharing information through Internet is very easy, cheap and fast method.
2. Collection of Information
A lot of information of different types is stored on the web server on the Internet. It means that billions websites contain different information in the form of text and pictures. You can easily collect information on every topic of the world. For this purpose, special websites, called search engines are available on the Internet to search information of every topic of the world. The most popular search engines are altavista.com, search.com, yahoo.com, ask.com etc. The scientists, writers, engineers and many other people use these search engines to collect latest information for different purposes. Usually, the information on the Internet is free of cost. The information on the Internet is available 24 hours a day.
You can get latest news of the world on the Internet. Most of the newspapers of the world are also available on the Internet. They have their websites from where you can get the latest news about the events happening in the world. These websites are periodically updated or they are immediately updated with latest news when any event happens around the world.
4. Searching Jobs
You can search different types of jobs all over the world, Most of the organizations/departments around the world, advertise their vacant vacancies on the Internet. The search engines are also used to search the jobs on Internet. You can apply for the required job through Internet.
Today, most of the commercial organizations advertise their product through Internet. It is very cheap and efficient way for the advertising of products. The products can be presented with attractive and beautiful way to the people around the world.
You can communicate with other through Internet around the world. You can talk by watching to one another; just you are talking with your friends in your drawing room. For this purpose, different services are provided on the Internet such as;
Internet telephony etc.
Internet also provides different type of entertainments to the people. You can play games with other people in any part of the world. Similarly, you can see movies, listen music etc. You can also make new friends on the Internet for enjoyment.
8. Online Education
Internet provides the facility to get online education. Many websites of different universities provide lectures and tutorials on different subjects or topics. You can also download these lectures or tutorials into your own computer. You can listen these lectures repeatedly and get a lot of knowledge. It is very cheap and easy way to get education.
9. Online Results
Today, most of the universities and education boards provide results on the Internet. The students can watch their results from any part of country or world.
10. Online Airlines and Railway Schedules
Many Airline companies and Pakistan Railway provide their schedules of flights and trains respectively on the Internet.
11. Online Medical Advice
Many websites are also available on the Internet to get information about different diseases. You can consult a panel of online doctors to get advice about any medical problem. In addition, a lot of material is also available on the Internet for research in medical field.
Although Internet has many advantages but it also has some disadvantages. The main disadvantages are:
Today, Internet is the most popular source of spreading viruses. Most of the viruses transfer from one computer to another through e-mail or when information is downloaded on the Internet. These viruses create different problems in your computer. For example, they can affect the performance of your computer and damage valuable data and software stored in your computer.
2. Security Problems
The valuable websites can be damaged by hackers and your valuable data may be deleted. Similarly, confidential data may be accessed by unauthorized persons.
Some websites contains immoral materials in the form of text, pictures or movies etc. These websites damage the character of new generation.
4. Filtration of Information
When a keyword is given to a search engine to search information of a specific topic, a large number of related links a displayed. In this case, it becomes difficult to filter out the required information.
5. Accuracy of Information
A lot of information about a particular topic is stored on the websites. Some information may be incorrect or not authentic. So, it becomes difficult to select the correct information. Sometimes you may be confused.
6. Wastage of times
A lot of time is wasted to collect the information on the Internet. Some people waste a lot of time in chatting or to play games. At home and offices, most of the people use Internet without any positive purpose.
7. English language problems
Most of the information on the Internet is available in English language. So, some people cannot avail the facility of Internet.
Electronic communication systems
Electronic communication is transmission of signals over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags or heliograph. In modern times, telecommunication typically involves the use of electronic devices such as the telephone, television, radio or computer. Early inventors in the field of telecommunication include Alexander Graham Bell, Guglielmo Marconi and John Logie Baird. Telecommunication is an important part of the world economy and the telecommunication industry's revenue was estimated to be $1.2 trillion in 2006
A number of key concepts reoccur throughout the literature on modern telecommunication systems. Some of these concepts are discussed below.
A basic Electronic communication system consists of three elements:
A transmitter that takes information and converts it to a signal;
A transmission medium that carries the signal; and,
A receiver that receives the signal and converts it back into usable information.
For example, in a radio broadcast the broadcast tower is the transmitter, free space is the transmission medium and the radio is the receiver. Often telecommunication systems are two-way with a single device acting as both a transmitter and receiver or transceiver. For example, a mobile phone is a transceiver.
Telecommunication over a telephone line is called point-to-point communication because it is between one transmitter and one receiver. Telecommunication through radio broadcasts is called broadcast communication because it is between one powerful transmitter and numerous receivers.
Analog or digital
Signals can be either analogue or digital. In an analogue signal, the signal is varied continuously with respect to the information. In a digital signal, the information is encoded as a set of discrete values (for example ones and zeros). During transmission the information contained in analogue signals will be degraded by noise. Conversely, unless the noise exceeds a certain threshold, the information contained in digital signals will remain intact. Noise resistance represents a key advantage of digital signals over analogue signals.
A network is a collection of transmitters, receivers and transceivers that communicate with each other. Digital networks consist of one or more routers that work together to transmit information to the correct user. An analogue network consists of one or more switches that establish a connection between two or more users. For both types of network, repeaters may be necessary to amplify or recreate the signal when it is being transmitted over long distances. This is to combat attenuation that can render the signal indistinguishable from noise.
A channel is a division in a transmission medium so that it can be used to send multiple streams of information. For example, a radio station may broadcast at 96.1MHz while another radio station may broadcast at 94.5MHz. In this case, the medium has been divided by frequency and each channel has received a separate frequency to broadcast on. Alternatively, one could allocate each channel a recurring segment of time over which to broadcastââ‚¬"this is known as time-division multiplexing and is sometimes used in digital communication.
The shaping of a signal to convey information is known as modulation. Modulation can be used to represent a digital message as an analogue waveform. This is known as keying and several keying techniques exist (these include phase-shift keying, frequency-shift keying and amplitude-shift keying). Bluetooth, for example, uses phase-shift keying to exchange information between devices Modulation can also be used to transmit the information of analogue signals at higher frequencies. This is helpful because low-frequency analogue signals cannot be effectively transmitted over free space. Hence the information from a low-frequency analogue signal must be superimposed on a higher-frequency signal (known as the carrier wave) before transmission. There are several different modulation schemes available to achieve this (two of the most basic being amplitude modulation and frequency modulation). An example of this process is a DJ's voice being superimposed on a 96MHz carrier wave using frequency modulation (the voice would then be received on a radio as the channel "96FM")
Modern operation of electronic communication systems
In an analogue telephone network, the caller is connected to the person he wants to talk to by switches at various telephone exchanges. The switches form an electrical connection between the two users and the setting of these switches is determined electronically when the caller dials the number. Once the connection is made, the caller's voice is transformed to an electrical signal using a small microphone in the caller's handset. This electrical signal is then sent through the network to the user at the other end where it is transformed back into sound by a small speaker in that person's handset. There is a separate electrical connection that works in reverse, allowing the users to converse
Optical fiber provides cheaper bandwidth for long distance communication
Radio and television
In a broadcast system, the central high-powered broadcast tower transmits a high-frequency electromagnetic wave to numerous low-powered receivers. The high-frequency wave sent by the tower is modulated with a signal containing visual or audio information. The receiver is then tuned so as to pick up the high-frequency wave and a demodulator is used to retrieve the signal containing the visual or audio information. The broadcast signal can be either analogue (signal is varied continuously with respect to the information) or digital (information is encoded as a set of discrete values.
Applications of Electronic Communication systems
Electronic communications adds a powerful new channel that not only will change how you use this mix of options, but it will create entirely new ways to interact. For example:
Electronic communications lets you combine numerous media - text, graphics sound, video, etc. - into a single message. That can result in far more meaningful communications tailored to the nature of your particular audience. In contrast to broadcasting, narrowcasting reflects the ability to develop numerous communications for subsets of your market or constituencies.
Electronic communications is interactive. It engages audiences in active, two-way communications. That requires a new way of thinking about advertising copy and the handling of public relations. The pay-off, however, is a self-selected audience, engaged and actively participating in the communications process.
Two-way communication is nothing new. But electronic communications creates a new form of many-to-many communications that lets geographically distributed groups communicate interactively and simultaneously through text, sound and video. You can hold inexpensive video conferences or press conferences from your desk, or conference with people at several desks located across the world. One of the burgeoning phenomena of the Internet is businesses and organizations sponsoring, supporting and moderating discussion groups about issues, products, strategies - anything of interest to the organization and its constituents. Sponsorships are also solicited for popular resources, such as indexes and other Internet search tools, and these provide a further communications and marketing opportunity.
Many organizations are using electronic communications facilities, such as the World Wide Web, as internal communications tools to enhance team work. Many individuals at different locations can work on the same documents, hold meetings and integrate research findings.
Electronic communications removes the power of communications gatekeepers to both positive and negative effects. Most organizations are used to controlling the messages that go out to its constituents through managers, spokespeople and others. But with the Internet, constituents begin to talk among themselves, requiring new approaches and a new emphasis on listening and reacting, not just talking.
With the Internet you have the ability to transmit and receive large amounts of information quickly to and from individuals and workgroups around the world. This changes the way activists, for example, can galvanize communities, inform legislators and change public opinion. It changes the sources and depth of your constituents' knowledge levels. It also lets those constituents reach you with new kinds of communications they may never have attempted before.
Disadvantages of Electronic Communication
The main issue with electronic communication is security. Your computer can be hacked and affected with computer virus. This can have an adverse effect on the computer system and the network. The volume of transmitted data is large and the transmission is fast. Hence, it becomes difficult for employers and managers to absorb, process and understand it and provide proper feedbacks to their employees. The speed with which the messages are transmitted often changes the structure of the messages, which at times can be misinterpreted. Electronic data can be duplicated identically without any proof of duplication. These messages can also be modified. At times, people can intentionally send malicious programs like viruses, worms and Trojans through emails, which is difficult to detect.
Another disadvantage of electronic communication is email privacy issues. An email is sent in the form of data packets via computer network. These data packets have to pass through a number of routers (a computer device used for forwarding packets in the computer network) and computers before it reaches its destination. So, there are chances of an individual tampering the emails before it reaches its recipient. While the data packets are transferred from one computer system to another, they can be lost when one router transfers it to another. If the router is bombarded with more number of data packets than its carrying capacity, the receiver can experience a delay in receiving it. The 'from message header' of a message can be modified, which hampers the authenticity.
Almost all technologies in this world have their pros and cons. Similarly, there exist advantages and disadvantages of electronic communication as well. In-spite of its disadvantages, most of us depend on electronic communication for our everyday work as it has become an integral part of our lives.