INTERAMERICAN UNIVERSITY OF PUERTO RICO





GIobal Networking:

Internet

ALVIN F. TORO BAHAMONDE








PROF. THOMAS PRYDE

IACG 2313

12/14/93






Thesis Statement:

Although it is a massive resource of information, people from the university community who could profit from its tremendous data bank fail to take advantage of it.

I. Preface

II. History of the Internet

III. Understanding how it works

           A. Packets and Addresses

           B. Usability

           C. Domain Name System

IV. Navigating Around

V. Finale


Global Networking: Internet

In the middle of the information age, our lives depend each day more and more on communication. The way we communicate has evolved through the years changing the methods in which information is produced and distributed. This has made a notable influence on the way we receive and perceive information. Information plays a vital role in the way we stay competent and therefore in this ever demanding world, the need for exceedingly large amounts of information is essential to our progress. This great need for information has led to technological advances which have brought the world closer, making long distances shorter, allowing us to travel to remote places faster and virtually putting the whole world at our fingertips.

One of these technological advances has been the development of computer networking. Networking is the method of connecting computers together in a way in which they can work with each other and share information. The Internet is an example of such a network and although it is a massive resource of information, people from the university community who could profit from its tremendous data bank fail to take advantage of it.

For those who do not know what is Internet, there really is no single definition to what word means. One can refer to the Internet as a group of linked networks that speak the same language (*TCP/IP protocol) or the group of people that use hose networks or the collection of resources that can be reached from those networks. There has never been one term agreed upon as to what the Internet is. Being such a controversial term, the best way to understand the Internet is by looking back at how it all started and follow its evolution to what it currently portrays.

Internet started more than twenty years ago as an experiment, while the U.S. Department of Defense was trying to connect together a network called the **ARPAnet and some other radio and satellite stations. The objective of the whole project was to build a communication system that would withstand catastrophes and still be functional.

In the ARPAnet network model (see Appendix A), communication will always occur between two computers: a source (the local terminal) and a destination (the remote terminal). It was designed to require minimum information from each end. To send a message through the network all one had to do was put its data into an envelope called Internet Protocol (IP) packet and switch it over to the destination with the correct "address".

*A protocol is a common method of communication between parties or in this case computers.

**ARPA = Advanced Research Projects Agency

With this packet switching technique, the source and destination computers were responsible for making sure that the packets got from one end to the other. Since the network itself was supposed to be unreliable and any portion of it could disappear without notice, the network was built around the idea that each computer would be able to serve as a pier or levee with any other computer. If for some reason some part of it were unavailable between the source and destination computers, the machines would automatically trace the next best route among the two and proceed to deliver the message. This model of networking proved to be very reliable because it not only permitted flawless connections but it also provided the only practical method for computers from different manufacturers to communicate. This was a very attractive idea for universities and other large institutions which did not own one standard set of computers. They could all use whichever computer they preferred and could still work over the network, sharing data files, programs or electronic mail.

As technology evolved and computer prices dropped, manufacturers started to put TCP/IP protocol into their machines. It was not too long before research institutions, libraries and large corporations started adopting the protocol to connect their computers together. This new demand started a communication standard that all institutions took benefit of. Since then, the Internet has not stopped growing. It is the fastest growing system of human communication in history. It has grown faster than telephone, television or fax. It currently connects over 10,000,000 computers, more than 20,000,000 users and grows 25% each month1.

To understand how Internet works, it is convenient to state a comparison between Internet and some other packet switched network. The postal service is a good example of a packet switched network.

Here, one does not have a dedicated piece of the network. What ever is going to be sent gets packed up with everybody else's things, put in a bag, transferred to the next Post Office and finally sorted out again.

One never has a direct route to your destination reserved for your data. The postal office decides how it is going to pack that data and send it to the next substation. Until the data reaches its destination, the whole process will be repeated from substation to substation.

Like the postal service, the Internet has a set of substations called routers. Routers are the computers in charge of sorting out all the data that moves through the network and sends it to other routers until the final destination is reached 2.

In order for the routers to know to which specific computer in the network the data is heading, it is necessary to assign a unique address to each computer on the network. Just like the postal service the data is put into an envelope, addressed and sent. The envelope in this case being a packet and the address (IP address) consisting of four sets of numbers smaller than 256 and separated by periods (154.217.56.21). The packets are small chunks of information not exceeding 1500 characters in longitude. Once data exceeds 1500 characters it is necessary to place the data in another packet and address it to the same destination as the first. In order to make sure that multiple packets get pasted the way they should on the destination compute; the Transmission Control Protocol (TCP) gives a number to each of the packets to assure that they are all pasted back in proper order on the destination computer. If for some reason any of the packets get lost or do not arrive, it asks the sending machine to retransmit/hem. TCP also has the power of detecting any errors in any of the packets and correcting them before pasting any more packets.

Although it all sounds very difficult, its actually extremely easy to get things from one place to the other. Considering that most of the work is done by the computers, all one really has to do is fill in the names. Through time vendors have developed software which automate the most common tasks and allow the user to concentrate on what needs to be done rather than on how to do it.

To make things even easier, another way of addressing computers was developed, putting names over the numbers. This naming process was called The Domain Name System. Its structure assigns names to the IP address numbers and separates them with periods: inter.ui.clu.edu.

Each name represents a domain with a certain level. The higher to the right, the higher the level (see Appendix B).

There can be any number of domains within a address, but in most cases there will be five or less. This naming system does not replace the IP address but only works on top of it making the process of addressing computers easier.

When the computer sees the address inter.ui.clu.edu, it proceeds to convert each domain name to an IP address. In order for the computer to link a domain name with an IP address, the name must be part of a worldwide database in which the computer will look it up. This database is located at the root computer which is the one et the highest domain or level (in this case edu). Once the source contacts this computer, it asks for the address of the computer at the next domain (clu). It then proceeds to contact clu and asks for the address of the computer at the next domain (ui). This procedure is the repeated until then last domain is reached (inter).

Once the outermost domain is reached, connection will be established. The user in the source computer can then proceed to work with the remote computer. In order to work more efficiently, Internet offers, some special tools that allows him to navigate around, making the journey easier. The most commonly used tools are telnet and ftp.

Telnet is used for logging into other computers across the network3. When connection is established, the source computer acts as if it were locally connected with the destination and is able to access the same information that can be accessed through a computer that is locally connected. This is the tool to use when connecting to public services and databases available all over the network.

FTP is used for moving files between computers4. Like telnet, the user can access public databases across the network with the difference that he can transfer any file he needs down to his terminal.

These two basic tools, are all the user needs to make a successful Internet connection. In a place where the concept of time and distance as we know it is redefined, it is hard to predict what you'll find. Being the Internet one undivided network, there are practically no frontiers.

Through the net, a computer that is physically thousands of miles away is just as close as a computer in the office next door. This means that any information that is available thousands of miles away is as near and available as if it were right next door. This is one of the most significant advantages of the network. One's computer does not need to be anywhere near the computer one wants to access to use the same services available to a computer that is.

All this adds up to say that any person using Internet can have the same access to any computer on the net as if he were physically on the other computer, no matter how far away it is. Once inside, the possibilities are endless. Best of all, a lot of the information found on the network is in the public domain and therefor free for the taking.

Even with all these advantages, not too many people in the university community benefit from Internet. Many do not even know it exists. This is due largely to the fact that many people still think that computers are difficult to learn and use. Hopefully some time in the future, people will start looking into Internet and will then unleash the true potential that lies within it.

Appendix A

Each computer is represented by a dot and connected by a line. If a connection were to be unavailable between two computers, the routers are capable of finding another path between the two points.

Appendix B

In the address above, inter is the domain name of a computer. This computer named inter is maintained by ui which is the main computer in a university. The university computer ui is part of a network named clu. This network named clu is part of a national group of educational institutions which classify to the domain name edu.

Notes

1 Tracy L. LaQuey, User's Directory of Computer Networks
(Bebford, MA: DigitalPress, 1989) 57.

2 Ed Krol, The Whole Internet: User's Guide & Catalog
(Sebastopol, CA: O'Reilly & Associates, 1992) 38.

3 Krol 67.

4 Krol 69.


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