of computers interconnected through some physical medium so that they can communicate. • We can classify these networks depending on their geographical extent; • a Local Area Networks (LAN) spreads over a limited geographical area and in contrast a Wide Area Network (WAN) connects computers over a much larger geographic area. • An internet work connects independent LANs and WANs to form one large network. Such a network is called an internet. • There is one such global internet that stemmed from an experimental network started by the Advanced Research Project Agency of the United States Department of Defense in 1960s. Directing Towards Success
together; some networks are connected to each other over a public telephone networks while others are connected over satellite links. • Now this network spans over political and geographical boundaries. • That particular internet is called the Internet. When we refer to this particular internet work we always capitalize the first letter “I”. • It is a wonder that computers communicate over this widely diverse and most often incompatible collection of networks. • This is possible because of a common set of rules that they all adhere to despite the differences in the individual LAN or WAN technologies. Such a set of rules used for communication is called a protocol and the protocol used in the Internet is called the TCP/IP protocol suite. Directing Towards Success
through out the world by connecting different types/levels of computers (from personal computers to high end workstations). • Although these computers are at homes, offices, schools/universities and government departments, it appears as an Information retrieval system with communication facilities to all users of the Internet. Directing Towards Success
very limited number of services (voice phone, fax etc.), • The Internet has unlimited number of services. At the same time, these services can be offered simultaneously (multi tasking environment) based on the users demand. • Applications which run (execute) at computers connected to the Internet can provide these services. • Ex : • Email • Instant messaging • Discussion forums (forums on website, news groups etc.) Directing Towards Success
computer to any other if it is connected through a network. • There are various types of resources available for information retrieval. • One major resource is web sites or home pages of organizations or individuals like www.cnn.com. • www.google.com is a very popular search engine. You can also find books and reports and repositories of software applications and so much more. Directing Towards Success
Do you have to pay for the Internet Access? • There are no owners for the Internet. Then you do not want to pay for it. • However, these networks should be developed and maintained by the providers. Therefore those who provide network connectivity (we call them Internet Service Providers) have to charge individuals/organizations when they want to access the Internet through their network. • Generally, there are two types of fees: One for the access time and the other one for the internet connectivity. Access time is usually based on the local telephone charges (e.g. Dial up Connection) or a fixed amount irrespective of access time. Directing Towards Success
a big impact on the society by revolutionizing the way people live and work in the everyday life. • There is a huge impact in several key areas like the Government sector, Commerce or Business sector, and also in Education sector. • On the other hand, the cost of some of services could bring to zero once they are provided through the Internet. For example, consider, voice calling to a long distance location through the Internet. • eGovernment • eCommerce • eLearning etc… Directing Towards Success
the Internet, by the late 1970s, many independent LAN networks were emerged due to two reasons. • First is due to the introduction of the inexpensive minicomputers. • Second reason is introduction of the inexpensive easy to install LAN technologies. • It is not always possible to connect multiple LANs together as different LAN technologies can be incompatible. • In 1960s and 1970s scientists came out with WANs that connected multiple computers across large geographical distances. • So with this a company with offices in several cities can install a WAN that links computers in each city. All attached computers can communicate with each other. However WANs cost much more than LANs. • Hence LANs were much popular than WANs. Engineers invented many WAN technologies most of them were incompatible with one another. Directing Towards Success
1970s, the U.S. department of Defense through Advanced Research Project Agency (ARPA) headed by J.C.R. Licklider had several computer networks to pass technology on to the military. • Its goal was to support military research about how to build a network that could continue to function in the midst of partial outages that could be caused by bomb attacks. It included a WAN called ARPANET. • ARPA also had the same problem in sharing resources. ARPA research examined how to interconnect all machines to form a large single network. • ARPANET also called as the backbone network, allowed smaller local networks to connect to it. Directing Towards Success
they were in effect connected to each other. In 1969 the Internet, then known as the ARPANET, was brought online under a contract let by the ARPA which initially connected four major computers at universities in the southwestern US. They are UCLA, Stanford Research Institute, UCSB, and the University of Utah. Directing Towards Success More info : http://www.w3c.rl.ac.uk/primers/history/origins.htm
of the technology that makes it possible to interconnect networks. • Two pieces of the Internet standards are, • IP • TCP • The Internet Protocol (IP) software which Provides basic communication, • Transmission Control Protocol (TCP) software which provides additional facilities that applications need. • Most of the time, the entire set of Internet Communication Software is identified as TCP/IP by the initials of the two components with a slash in between. Directing Towards Success
other, they must know the same language. • Just like that, computers on the Internet must know the same language or adapt to a set of standard rules to communicate with one another and the term, • protocol, is used to refer the standard rules of communication. • Hence, the standards or rules of communication on the Internet (i.e. The Internet Protocol) are known as TCP/IP. Directing Towards Success
encourage vendors to adopt Internet technology. • Whenever a researcher discovered some thing important took measures to document the results in a report. • ARPA made all reports available to public. • Ref : http://www.ietf.org Directing Towards Success
used and the TCP/IP technology had been tested. • Some of the academic and industrial research sites were using TCP/IP regularly. • U. S. military also started to use TCP/IP and chose the internet as its primary computer communication system. • By 1983, ARPA expanded the Internet to include all military sites connected to the ARPANET. • The date, Marked a transition for the Internet as it changed the Internet from an experiment to a useful network. Directing Towards Success
the Internet interconnected approximately 200 computers. One year later, it had doubled in size. Increase in Internet size uncovered limits in TCP/IP. • As more and more computers connected to the Internet the TCP/IP couldn’t accommodate all. • There was a need to update TCP/IP to increase the capacity and also required tuning of administrative procedures by professional staff. • The National Science Foundation funded a project (CSNET) to build the Computer Science Network. CSNET encouraged institutions to use TCP/IP to connect to the Internet. Directing Towards Success
research. They could exchange documents or experimental data instantly and also used the Internet to disseminate data as experiments proceed. • So the scientists could analyze the results of experiments done at a remote place without traveling and also used the Internet for informal, unpublished discussions. • Recognizing the importance of the Internet to the science, NSF decided to fund Internet growth and TCP/IP technology. In 1986, the National Science Foundation funded NSFNET as a cross country 56 Kbps backbone for the Internet. • This network was much smaller and not much faster than the ARPANET. Later NSF decided to extend network access to every scientist. Directing Towards Success
past. • This is mainly due to the fact that the services and opportunities available through the Internet are growing very fast. • According to the recent statistics, a computer is added to the Internet in every second. • It is expected the number of computers connected to the Internet will be doubled in every 10 months and the growth now has exponential trend. Directing Towards Success
access growth of the Internet, • it is necessary to develop technological capabilities and infrastructure of the Internet. Many international organizations and governments are contributing to improve the Internet. Directing Towards Success
Corporation for Advanced Internet Development (UCAID), Internet2 is a partnership between universities, corporations and government agencies. • Internet2 is not a single network, but a consortium of hundreds of high-speed networks linked by fiber optic backbones that span the United States and links to other countries. • The network transmits data at speeds up to 2.4 gigabits per second–45,000 times faster than a 56 Kbps modem– allowing scientists to test their laboratory discoveries in the real world. Directing Towards Success
of users are increasing. Current statistics say that the largest portion is from US and Europe. However, Asian users are rising rapidly. • The Internet has become a resource irrespective of profession or status. At the same time, their usage objective varies and some individuals may have different objectives. • For example, children, parents, teachers and researchers may access the Internet mainly for education purposes and stockbrokers and different business professionals for business purposes. • Anyone can connect to the Internet through telephone lines since these two networks are connected. You need a device called a modem to connect your computer to Internet through a telephone line. Directing Towards Success
business, trade, commerce and industry, the Internet also provides tremendous opportunities to students, researchers and professionals for getting information on matters related to academic and professional topics. • In addition to that the Internet is a source of information it is a good source of entertainment too. Directing Towards Success
and share information in a number of ways. • Two of the most popular uses of the Internet are electronic mail and the World Wide Web. • We can also find several other useful services like Instant messaging, video conferencing, FTP, newsgroups, etc. Directing Towards Success
is sometimes called as w3 or web is the most popular and powerful application on the Internet. • It was originally created to build the infrastructure for sharing documents on the Internet. Since different types of computers will access these documents, it was decided to have a standard structure for them. • This standard was called HTML (Hyper Text Markup Language). • Today the web is a huge collection of documents stored on computers around the world. Directing Towards Success
called SGML (Standard Generalized Markup Language). • Hence web documents usually have html markup commands to format these documents. It was called web since html gives facilities to link documents with respect to specific location. • These locations are identified using file addressing mechanism called URL (Uniform Resource Locator). • URL identifies a file using its physically stored location, file name and if necessary segment name in the file. Directing Towards Success
you can get an address called the email address. • Then others can send you messages to your email address and you can read them when ever you want. • This is like when you give the postal address of your home, others can send mails to your address. • Post mail takes time and more cost than emails. • Emails are instant and the cost of delivery is very small. • Do you have an email address? If not, do you like to get one? How much will it cost? It is just few keystrokes and you can get one for free too. • We will learn more about emails later. Directing Towards Success
a very famous activity that people engage through the Internet. • When two or more people are online (i.e. they are connected to the Internet at the same time), they can exchange messages in a private group or as an open chat room where anyone else can participate with or without their permission. • Email based communication is considered as the asynchronous method of communication where participants do not want to be online. Directing Towards Success
communication and it opens a direct interactive environment. • Earlier, chatting is done using simple text messages since it doesn’t take much time for the transmission. • With the development of the Internet speed and bandwidth, people can now do chatting using audio and video streams just like in a real-time communication. • Irrespective of the medium of chatting, it is almost free except the charges to access the Internet. Directing Towards Success
two or more parties using video streams and special hardware in a real time communication. • Since video stream requires better (bandwidth) and faster (speed) connection, it is not a very popular way of communication on the Internet in early days. • Video conferencing is more than mere communication and it may involve more collaborative activities. • Video conferencing tools provide additional facilities for active collaboration, for example white boards. Examples for video conferencing include MSN messenger for video conferencing or Microsoft Net meeting Directing Towards Success
mechanism due to the better technological infrastructure of the Internet. • You need a video camera, microphone attached to a computer to start video conferencing with another party on the Internet. Directing Towards Success
one or very few individuals you can send it by email. • However, if you want to start a discussion based on these messages, emailing is not the best option. • Newsgroups serve this purpose and it provides an interface for such discussions. Simply, you can send a message to a newsgroup and then all people who are in this group can see your posting and reply to it. • Such replies also appear in this newsgroup. It also can be considered as an electronic bulletin board. • “Usenet” is one such famous newsgroup but there are several others. Directing Towards Success
a standard way to copy files from one location to another (i.e. from one machine location to another location in the same or different machine). • You can use FTP to download files to your machine from a location in another machine. • However, you need to login into these machines in order to obtain the permission. • There are some public locations on the Internet from which you can download files by just giving your identification information if you like. • In order to simplify the process of accessing files through FTP, there are several applications just like web browsers. • Then, users do not need to know complicated commands and they can copy files or directories just like copying files on the desktop. Directing Towards Success
on the Internet or local area network (LAN) connections. • The Telnet program runs on your computer and connects your PC to a server on the network. You can then enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. • This enables you to control the server and communicate with other servers on the network.
1. Runs at the Web Server. 2. Runs at the client computer 3. Can be used to do spell checking. 4. Can be used as a virus guard 5. Is able to find a web page for a given URL Directing Towards Success
Type of ARPANET , and what it stands for, (i) Its a LAN, Advanced Research Project Agency (ii) Its a WAN, Advanced Research Project Agency (iii) Its the internet, Advance Research Project Agency (iv) It’s a WAN, Advance Research Project Agency (v) It’s a MAN, Advanced Research Project Agency. Directing Towards Success
Higher Transfer Protocol and File Transfer Protocol. (b) Hyper Text Transfer Protocol and File Transfer Protocol. (c) Higher Transfer Protocol and Form Transfer Protocol. (d) Hyper Text Transfer Protocol and Form Transfer Protocol. (e) Hyper Text Transpose Protocol and Form Transpose Protocol. Directing Towards Success
those of the Column B. Column A Column B 1 Web Browser a www.amazon.com 2 Web site b Internet Explorer 3 URL c Web address 4 Search engine d ftp 5 Internet service e www.Google.com Which of the following gives a correct matching of the contents of Column A with those of Column B? (a) (1= b), (2 = a), (3 = c), (4= e), (5 = d) (b) (b) (1= b), (2 = e), (3 = c), (4= a), (5 = d) (c) (1= e), (2 = c), (3 = d), (4= b), (5 = a) (d) (1= e), (2 = a), (3 = c), (4= b), (5 = d) (e) (1= c), (2 = a), (3 = b), (4= e), (5 = d) Directing Towards Success
need to know (a) The address of the computer. (b) The country in which the computer is physically located. (c) The URL of the web site. (d) The name of the web master. (e) The address of the nearest router. Directing Towards Success
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