PHYS 510 - Internet Notes

Internet Overview and Resources

This is directly adapted from web sites previously maintanced by Prof. John Evans
Latest Modification: January 20, 1998

History of the Internet

There are several histories of the Internet available on the Web. Rather than trying to reproduce some already excellent histories of the Internet, I will simply provide the links to some selected documents, which are not exhaustive by any means. One should also consult the October 1996 issue of Physics Today which is a special issue entitled - 50 Years of Computers and Physicists. Although, the four articles in this issue - The Computing Revolution and the Physics Community by Alfred E. Brenner, From Mars to Minerva: The Origins of Scientific Computing in the AEC Labs by Robert W. Seidel, Probing Cosmic Mysteries by Supercomputer by Michael L. Norman, and Data Acquistion and Analysis in Extremely High Data Rate Experiments by Joel N. Butler and David R. Quarrie - are not specifically about the Internet, they do provide a context for the role of the Internet in computational physics.
One of the key organizations, particularly in the history of the Web component of the Internet, is CERN [A Short History of Internet Protocols at CERN]. Another reasonably good and up-to-date site is one developed by PBS [History of the Internet].

What Is the Internet?

What comprises the Internet is difficult to answer since it changes with time, but basically it is a cooperation of all the networks using the TCP/IP protocol suite for data exchange to form a seamless network for the support of their collective users. Not all of the networks cooperating use the IP protocol, but they are not the major constituent. The model for data exchange is called the client-server model.
As to who governs the Internet, it is not a corporation or federal agency, so there is no president, chief operating officer, or agency head. Although individual networks may have a single authority figure, that is a different issue, but there is none for the Internet as a whole. The Internet Society (ISOC) is a voluntary membership organization whose purpose is to promote global information exchange through Internet technology. ISOC appoints a council, called the Internet Architecture Board (IAB), which adopts standards and allocates resources, such as addresses. The Internet Engineering Task Force (IETF) is another volunteer organization which meets regularly to discuss operational and near-term technical problems of the Internet. The IETF uses working groups to address important questions in operation or technology. This cooperative mode of operation is what makes the Internet uniquely the Internet.
Since the Internet is not a centralized organization, no one pays for it as a whole. Each cooperating network pays for its part. Networks meet to discuss how to connect themselves and to pay for that connection. The operations of the cooperating networks is diverse and can not be characterized by any single organizational or operational plan.
What are the consequencies of this cooperative arrangement for individual users? Not much. The functioning and growth of the World Wide Web component of the Internet is a clear indication that, like the telephone, individual users are basically unaware of whose network they are using in order to make their connections and transfer information.
What does the future hold for the Internet? Undoubtedly a great number of discussions are going on world-wide all the time about the future of the Internet. Some of the resource links provided here will lead you to some of these discussions and proposals.

How Does the Internet Accomplish Data Interchange?

Data interchange on the cooperating networks composing the Internet is somewhat analogous to sending a book one page at a time through the postal service. TCP software package contains the protocol responsible for accomplishing this task. In a somewhat over simplified statement of its operation, TCP breaks the information to be transmitted into pieces, numbers each piece so that receipt, verification, and reassemble can be accomplish at the other end, places the data in a TCP envelope which in turn is placed inside an IP envelope, and gives it to the network.
On the receiving end, TCP software collects the envelopes, extracts the data, and puts it in the proper order. Should some data be missing or corrupted, TCP asks the sender to retransmit them. Once it has all the data in proper order, TCP passes the data to whatever application program is using it services.
Some of the activities that operate over the Internet are (see Chapter 4 in Landau and Fink):
Electronic mail and the World Wide Web will be considered below in somewhat more detail.

Internet Resources

One source of information about the Internet is provided by the University of Illinois [The Internet], which provides a diverse set of links on all aspects of the Internet. Other resources are given below.

E-mail

Rapid communication is one of the hallmarks of modern science and technology, particularly physics and astronomy. Although email and the Web will undoubtedly lead to some embarrassment or abuse, for example the premature dissemination of results, rapid communication has become an integral part of the practice of science and engineering.
One component of the Internet activities is electronic mail. Almost every computer system has its own electronic mailing system; often the formats are incompatible. However, ther is one format which is widely used in many computer networks identified by the document that identifies it - RFC822. Although it originated as a standard for US research networks, it is now widely supported throughout the world's research and development networks and is in fact the de facto standard.

World Wide Web

Another component activity on the Internet that is effecting the practice of science and engineering is the World Wide Web. For more information see the course notes on the World Wide Web.