Student: James Higginson
Course: An Introduction to the Internet

What is the Internet?

There are many different definitions of the Internet and many people
often confuse the Internet with some of the applications, which run on it, such as E-Mail, World Wide Web and File Transfer Protocol (FTP).

So what is the Internet? In general terms, the Internet is a system of
computer networks, a network or networks that allow users of the Internet to exchange information, files or even talk directly to users of other computers around the world, through the use of set protocols.

To give you an indication of the size of the Internet, the following map
shows the number of hosts on the Internet throughout the world as at July 1999.

Copyright © 1999 MIDAS

Student: James Higginson
Course: An Introduction to the Internet

The Internet was not an overnight development, it has evolved over thirty years and can be traced back to the first computer networking projects, the key developments & personalities of which will be explained in this section.

Following the launch of Sputnik (the first artificial earth satellite) by the USSR in 1957, the US Department of Defense formed the Advanced Projects Research Agency (ARPA) to establish a lead in world technology for the USA.

The first head of this organisation was J.C.R. Licklider, who wrote a series of memos in 1962 discussing his ideas of a “Galactic Network”, a global set of computers that were interconnected and allowed users to access data and programs from any site. He promoted his networking theory to his successors at ARPA, Ivan Sutherland, Bob Taylor and Lawrence G Roberts.

In 1965, Lawrence Roberts directly connected a TX-2 computer at MIT in Massachusetts to a Q-32 computer in California via a dedicated phone line. This experiment was the first-ever Wide Area Network (WAN), (the first Local Area Network (LAN) was developed some years later by Bob Metcalfe at Xerox PARC, using the Ethernet protocol, which is probably the dominant network technology on today’s Internet).

The experiment proved that time-sharing computers could network but it also proved that the circuit switching was not adequate and he approached ARPA to develop the computer network concept further. The result was his plan for the ARPANET, a number of individual computers connected by leased lines using packet switching. Roberts had been convinced on the theory of using packet switching by Leonard Kleinrock, who wrote the first paper on packet-switching theory in 1961, although three independent bodies worked on this concept, the National Physical Laboratory (NPL), RAND and MIT.

The first four nodes of ARPANET were at UCLA, Stanford Research Institute, UC Santa Barbara and University of Utah and these formed the initial ARPANET in 1969. The Network Working Group, headed by Steve Crocker, finished the initial ARPANET Host-to-Host protocol in 1970 which was called the Network Control Protocol (NCP). The implementation of this protocol enabled the network users to develop applications.

Bob Kahn, who had been working at Bolt Beranek & Newman (BBN), the company which had built the Interface Message Processors (IMPs) of the ARPANET, posed the problem of how computers could interwork without any knowledge of the characteristics of the underlying networks as there were more than one packet switched network. Bob Kahn employed the skills of Vint Cerf (previously involved in the design of NCP and the measurement of ARPANET) to establish a solution to getting these to “internetwork”. They concluded that the following key features were needed:

• Using computers as gateways or routers between different networks
• Making hosts responsible for end-to-end transmission of packets together with error correction and retransmission if necessary
• Devising the protocols necessary to make the first two points happen

In 1974 Bob Kahn and Vint Cerf published “A Protocol for Packet Network Interconnection” which specified the Transmission Control Protocol (TCP). This new protocol, TCP, was eventually split into Transmission Control Protocol/Internet Protocol (TCP/IP) to make it even more efficient. In the early 1980s, TCP/IP was established as the protocols on the ARPANET, replacing the NCP.

Through the 1980’s ARPANET was revised, and new networks were established including NSFNET, but TCP/IP was essential to them all. More and more networks have interconnected to form the Internet. Vint Cerf has stated in an online interview:

“Today, there are an unknown number of networks interconnected to form the Internet – certainly in excess of 200,000 around the world and likely more than that. There are at least 60 million computers on the Internet and possibly as many as 200 Million.”

As the Internet and its capabilities has developed, more protocols have been added in a layered approach in addition to TCP/IP, such as the Domain Name System (DNS), the email protocols POP3, IMAP, and SMTP) and the World Wide Web protocols (HTTP, HTML, and XML).

One of the keys to the rapid growth of the Internet has been the availability of basic documents and specifications of the protocols. These were available as Requests for Comments (RFCs). Jon Postel acted as the RFC Editor; in addition to his role as director of the Internet Assigned Numbers Authority, a non-profit body that administers the required protocol number assignments.

It could be claimed that J.C.R. Licklider was a forefather of the Internet, as his ideas of a “Galactic Network” do have a resemblance to the current Internet. He promoted the theories of networking to his successors at ARPA, without whose funding the development of ARPANET and hence Internet could be called into question.

Robert Kahn was responsible for the system design of the ARPANET whilst at Bolt Beranek and Newman (BBN). After joining ARPA, he conceived the idea of open-architecture networking, the underlying principle of the Internet, which led him to co-develop the protocols required to make the Internet a reality, namely TCP/IP.

Through working for Leonard Kleinrock, Vint Cerf helped to develop the host level protocols of the ARPANET and then on software for the Network Measurement Centre, which measured the performance of the ARPANET. His work led him to work with Robert Kahn in co-developing the protocols, TCP/IP.

Jon Postel is often touted as a father of the Internet. Indeed, he had a significant part to play in the development of the Internet, through his control of the Requests for Comments and founder of the Internet Assigned Numbers Authority.

For the Internet to exist there had to be a method of embracing open-architecture networking, this was only possible through the introduction of TCP/IP. I therefore believe that Robert Kahn and Vint Cerf have the strongest claims to be called father(s) of the Internet, In fact Vint Cerf maybe more so, he has continued to nurture and promote the Internet (as any father would do) through his roles as President of the Internet Society (the closest thing the Internet has to a governing body), Chairman of the Internet Societal Task Force and his work at the Jet Propulsion Laboratory to design an interplanetary Internet. Kahn and Cerf received the U.S. National Medal of Technology from President Clinton in December 1997, for founding and developing the Internet.

However, if we the use concept of Systems Thinking, i.e. looking at the whole, then the development of the Internet has relied on more than just the development of TCP/IP, developments such as packet-switching were vital, the freedom of information provided by Jon Postel enabled rapid growth, and support of Government in providing an envirnoment & funding for it to have been developed. In fact, Vice President of USA, Al Gore, has even claimed his role:

"During my service in the Unites States Congress,
I took the initiative in creating the Internet"

The Internet may have two father figures in Vint Cerf and Robert Kahn but there are many more who have a valid claim to its birth. The media will always look for an inventor or creator, but in this instance there is a whole family who are responsible for the fatherhood of the Internet.

Student: James Higginson
Course: An Introduction to the Internet

Click HERE to view my plan for this assignment

Katie Hafner, Matthew Lyon, Where Wizards stay up late – Touchstone Publications – 1998

Katz, John, “Mourning the Father of the Internet” – 27/10/98 –
(visited 30 August 2000)

Rodriguez, Karen, “Plenty deserve credit as ‘father’ of the Internet” – 25/10/99
http://www.bizjournals.com/sanjose/stories/1999/10/25/newscolumn2.html
(visited 30 August 2000)

The Corporation for National Research Initiatives, “Robert E Kahn biography” – 18/08/00
<http://www.cnri.reston.va.us/bios/kahn.html>
(visited 30 August 2000)

Worldcom, “Vinton G Cerf – Personal Prospective”
(visited 30 August 2000)

The Internet Engineering Task Force
<http://www.itef.org>

Vint Cerf & Robert Kahn, “A Protocol for Packet Network Intercommunication” – May 1974 –
(visited 30 August 2000)

The Internet Society (ISOC)
<http://www.isoc.org>

Robert Hobbes’ Zakon, “Hobbes’ Internet Timeline v5.1” – 01/07/00
(visited 30 August 2000)

Worldcom, “Cerfs Up: Internet History”
(visited 30 August 2000)

Whatis.com
<http://www.whatis.com>

Open University – T171 Course Material
<http://www.open.ac.uk>

N.B. I did email Vint Cerf at http://www.worldcom.com to find out if he is comfortable with the title “father of the Internet”. Unfortunately, as of 01/09/2000, I have not received a reply.

Tutor’s note: Vint Cerf’s very generous reply arrived a few days after the assignment went into the Open University’s inflexible assessment system – but I had already given the student extra points for this initiative. Both of us were justified when Vint Cerf’s assessment turned out to be almost identical to the ‘conclusion’ of the assignment.

Essay plan as a mind map

Student: James Higginson
Course: An Introduction to the Internet

Definitions

WAN
A WAN is a network that covers a large geographical area. Each node in a WAN may be located in a different town. A mainframe or minicomputer will usually be involved somewhere in a WAN.

LAN
A LAN is a network that covers a smaller area than a WAN. Typically a LAN will serve the needs of one institution at one site. For example a university will have their own LAN, as may an individual bank. LANs often connect to other LANs and to WANs to allow communication between them. These interconnected LANs and WANs form a network of networks commonly known as the Internet.

Ethernet
Ethernet is a network protocol for LANs. It operates on a bus network topology. It was developed by Bob Metcalfe at Xerox PARC and is the most popular method of LAN protocol. Its popularity is a result of its reliability, speed and relative cheapness.

Networks
The public telephone network is officially known as the Public Switched Telephone Network (PSTN). While switchboard operators were replaced by mechanical, and later by computerized switching equipment, and optical (glass) fibre has replaced much of the copper wiring, the function of the network is still simply to connect the wires of two telephones (or compatible devices such as fax machines or modems), so that sounds coming from one end are transmitted to the other. This is called a ‘circuit-switched’, or more simply ‘switched’, network architecture.

Circuit Switching
While this system is very reliable, it is also extremely inefficient and expensive because the connection is made at the beginning of a conversation, fax transmission, or modem ‘session’, and is maintained until the connection is terminated – meaning a certain portion of the network is reserved exclusively for that conversation whether or not communication is taking place at the moment. If one party puts down the phone or is silent, or neither computer is sending or receiving data for a period of time (as is the case when using the Internet), that circuit as well as the ‘ports’ on the phone switches between the two devices are still unavailable for other activity even though they are not being used at the moment. Since it is estimated that up to 50% of a typical voice conversation is actually silence, clearly a tremendous amount of network capacity is wasted. (Put another way: a company must build double the network it really needs for a given number of simultaneous calls at double the cost.)

Packet Switching
Packet networks break the digital stream of ones and zeros into chunks of the same length. These chunks, or ‘packets’, are then put in the computer equivalent of an envelope, with some information such as the origin and destination, or ‘addresses’, of the packet, and a serial number that indicates the sequence number of the packet – its ‘place in line’. In the place of switches which merely connect and disconnect circuits, packet networks use routers – computers that read the address of a packet and pass it to another router closer to the destination. At the destination, a few thousandths of a second later, the packets are received, reassembled in the correct order, and converted back into the original message. Here is an illustration of how it works:

Packet Switching – How it works
The routers in a packet-switched network are permanently connected via high-speed lines. This may seem expensive at first sight, but it makes sense economically (and technically) if the network is heavily used, i.e. effectively flooded with packets.

TCP/IP
The Internet works by breaking long messages into smaller chunks called packets which can then be switched through routers until they reach their destinations. The software associated with the TCP/IP family of protocols takes care of the assembly, disassembly and addressing of packets.

Anatomy of a Packet

Essentially, a packet is a string of bits divided into different segments. At its core is a Data segment (the chunk of the original message) which is sometimes referred to as the payload. In order to arrange for the passage of the payload through the Internet, extra information is added to it in the form of headers or (occasionally) trailers

TCP was eventually split into two protocols – one (IP) to handle addressing of packets, the other (TCP) to deal with their assembly and disassembly. The design philosophy behind this was the belief that it was better to have specialised protocols which each did one job and co-operated with one another rather than trying to design one, all-embracing monolithic protocol which tried to do everything.

DNS
The Domain name system (DNS) is the way that internet domain names are
located and translated into Internet Protocol addressess. A domain name is a
meangingful and easy-to-remember “handle” for an internet address.

POP3
POP3 (Post Office Protocol 3) is the most recent version of a standard protocol for receiving e-mail. POP3 is a client/server protocol in which e-mail is received and held for you by your Internet server. Periodically, you (or your client e-mail receiver) check your mail-box on the server and download any mail. POP3 is built into the Netmanage suite of Internet products and one of the most popular e-mail products, Eudora. It’s also built into the Netscape and Microsoft Internet Explorer browsers.

IMAP
IMAP (Internet Message Access Protocol) is a standard protocol for accessing e-mail from your local server. IMAP (the latest version is IMAP4) is a client/server protocol in which e-mail is received and held for you by your Internet server. You (or your e-mail client) can view just the heading and the sender of the letter and then decide whether to download the mail. You can also create and manipulate folders or mailboxes on the server, delete messages, or search for certain parts or an entire note. IMAP requires continual access to the server during the time that you are working with your mail.

SMTP
SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it’s limited in its ability to queue messages at the receiving end, it’s usually used with one of two other protocols, POP3 or Internet Message Access Protocol, that let the user save messages in a server mailbox and download them periodically from the server. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving messages that have been received for them
at their local server.

HTTP
The Hypertext Transfer Protocol (HTTP) is the set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. Relative to the TCP/IP suite of protocol, HTTP is an application protocol. Essential concepts that are part of HTTP include (as its name implies) the idea that files can contain references to other files whose selection will elicit additional transfer requests.

HTML
HTML (Hypertext Markup Language) is the set of “markup” symbols or codes inserted in a file intended for display on a World Wide Web browser. The markup tells the Web browser how to display a Web page’s words and images for the user.

XML
XML (Extensible Markup Language) is a flexible way to create common information formats and share both the format and the data on the World Wide Web, intranets, and elsewhere. For example, computer makers might agree on a standard or common way to describe the information about a computer product (processor speed, memory size, and so forth) and then describe the product information format with XML. Such a standard way of describing data would enable a user to send an intelligent agent (a program) to each computer maker’s Web site, gather data, and then make a valid comparison. XML can be used by any individual or group of individuals or companies that wants to share information in a consistent way.

Student: James Higginson
Course: An Introduction to the Internet

Congratulations on your essay James. It’s a substantial piece of work, and you have done well. I realise that the last few weeks on the course have been tough – and it’s to your credit that you’ve stuck at it.

These are my comments, made as I go through the script. Please bear with me, because I am trying to use the marking software, which is a bit temperamental.

&& – indicates where marks have been gained

** – indicates where marks have been lost

Try to avoid posing your argument in the form of questions. Even if they are answered, they usually have the effect of leading away from the question which has been asked.

Very good that you give full references to all your sources. &&

I liked the definitions of LAN and WAN which you put in as links [which worked well]. This shows your exploiting the potential of HTML. &&

[This is a very small detail] I think the references to your sources might look better as footnotes [with links]. This would leave the web essay itself less ‘cluttered’.

I also liked the fact that you made a well-reasoned attempt to ‘answer the question’ [though I was a little surprised that Donald Davies didn’t get a mention].

Your report/essay is thorough, well-executed, and effective. All the links work, and I liked the way you used the horizontal rule to emphasise the structure.

Your plan is good and shows your clear-thinking skills – &&

Your writing is clear, to-the-point, and ‘objective’ – in just the way which is required for academic work. &&

I am also giving you maximum bonus marks for having emailed Vint Cerf. Even though his reply was too late to go into the web essay, I have seen it in the conference, and I think it is in the spirit of the web that you could add it to your assignment.

You have now completed four essays – which means that there’s only the End of Course Assignment to go. You are heading towards successful completion of the course!

Copyright © James Higginson 2000