Course Content

 

While it is telecommunications hardware that provides the path for using the World Wide Web, all the hardware would be worthless without programs that actually do the work for you. In this lesson we will begin with a review of the current state of the Internet (see below, then spend some time reviewing how we got to this point. There is so much content that we need to break it up into several lessons. This cycle we will look at the Internet beginnings, the formation of the World Wide Web, and the basics of how browsers work. In the next cycle we will look at the evolution of HTML and how WEB 2.0 came about (that which provided the kernel for social networking and file and data management on the Web) and standardization — plus a peek into the future (HTML5). So, sit back and enjoy, it is indeed an interesting history lesson.

So What IS the Internet?

This five minute video provides a basic overview:

Current State of the Internet

Now, let’s take a look at the evolution of the Internet and how we go to this point:

This video provides you some idea of the volume of traffic on the Internet:

Go to top

So, How did we get here… really?

 

This entry clip from Robert Cringley’s show produced for NPR back in the late 1990s is a good way to start:

Ok ok in 1996 they predicted that the Web would take over the world. And they were close. But for sure they had no idea how entrenched it would become in our society (or did they?)

As a point of reference, the best Known Internet History Timeline comes in the form of Hobbes’ Internet Timeline

How it all got started… really

1945: Vanevar Bush publishes paper on memex machine.. A machine intended to change the way people store and retrieve books, records, and notes… to augment “human memory”… people did not take him seriously. Meanwhile from another side of the world, another visionary had his own ideas about Xanadu:

OK so Ted Nelson has thin skin about his ‘discovery’. And yes there seems to be some bitterness about Tim Berners-Lee’s ‘invention’ So just who was this Berners-Lee guy anyway?

How it all Got Started

I guess we can all thank the Russians. Back in the 1950s right after the War, folks in the USA were getting back to normal, resting on their laurels, thinking the USA was the king of the world. Education (especially higher ed) was suffering.. kids went to school to party. Math and science education/focus fell to the wayside. The along came Sputnik to change our lives for ever:

The Architecture Behind it All

Actually there were two parts:

Part #1 – The Software:

The initial design was based on two visionaries:
a) J.C. Licklider from MIT:

“Lick” then moved to DARPA to develop it..
Leonard Kleinrock (at UCLA) developed the theory of packet switching. “Information Flow in Large Computer Nets” as a doctoral thesis..

Lawrence Roberts of MIT in 1965, connected their computers with a California computer, showing the value of packet switching but also the inadequacies of conventional telephone line switches.

Roberts also moved over to DARPA

Part #2: The Interface Message Processor (IMP)

As DARPA was funding several universities’ research budgets, it asked that they join the ARPA NETWORK. Most were reluctant to join, due to confidentiality issues… but DARPA PREVAILED. The ARPANET was brought online in 1969, connecting UCLA, Stanford, UCSB, and the University of Utah:

To build the network, ARPA called upon an emerging company out of Cambridge, MA (also the home of MIT):

Transforming DARPA into a commercial venture

So the rest, as the say is history. But to transform this basically military operation into a commercial venture took some new players,
As DARPA was non-commercial, it took literally ‘an act of Congress” to begin the transformation:

 

It also took some new technology… namely, the browser… enter “Mosaic”… One of two original “killer apps” on the Internet. We explore how that all came about in our lesson on How Browsers Work.

So just what is the definition of the Internet?

“A global information system that:

• is logically linked together by a globally unique address space on IP or its subs. Follow-ons.
• is able to support communications using TCP/IP or its follow-ons, and/or other IP compatible protocols.
• provides, uses or makes accessible, either publicly or privately, high level services layered on communications and related infrastructure described herein.”

And What is the WORLD-WIDE WEB?

It is an assortment of computer systems connected by the Internet employing a common protocol (standard) HTTP sending and receiving hypermedia documents…
well not exactly.. it has evolved into a second iteration (Web 2.0) that we will discuss later on (and eventually Web 3.0)…. but for now, here is the picture of what is known as the ‘backbone’:

all based on Web Browsers and hyperlinks:

• electronic documents containing multimedia information
• hyperlinks (text-based “links”) to cross-reference pages and resources
• these links provide automatic access

 

On the server side:

Web servers that provide:

• remote systems that store Web documents
• process client requests and send resources
• access to databases
• hypermedia documents are “navigated” using these links

---

 

Internet ‘apps”

 

• electronic mail (2nd “killer app” for the Internet)
• telnet (computer-to-computer)
• file transfers (FTP)
• World Wide Web (WWW)
• asp & php

 So, the World Wide Web is actually a bundle of huge ‘apps’ (applications) found on the Internet… 

---

 

Basic Protocols

 

• TCP – for networks
• IP – for packets
• TCP/IP – Internet
• HTTP – for web pages (w/in TCP/IP)
• FTP – to transfer files (w/in TCP/IP)

 

What is TCP/IP?

(transmission control protocol/Internet protocol)

 

• It was developed by a Department of Defense (DOD) research project (ARPA) to connect a number different networks designed by different vendors into a network of networks.
• It was initially successful because it delivered a few basic services that everyone needed (file transfer, electronic mail, remote logon) across a very large number of client and server systems.

Features

• Several computers in a small department can use TCP/IP (along with other protocols) on a single LAN.
• It is composed of layers:
  

  IP – is responsible for moving packet of data from node to node. IP forwards each packet based on a four byte destination address (the IP number). The Internet authorities assign ranges of numbers to different organizations. The organizations assign groups of numbers to their departments. IP operates on gateway machines that move data from department to organization to region and then around the world.

  TCP – is responsible for verifying the correct delivery of data from client to server. Data can be lost in the intermediate network. It adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.

  Sockets – is a name given to the package of subroutines that provide access to TCP/IP on most systems.

• The IP component provides routing from the department to the enterprise network, then to regional networks, and finally to the global Internet.
• This network design allows the construction of very large networks with less central management.
• The downside is that, because of its ability to automatically recover, network problems can go undiagnosed and uncorrected for long periods of time.

What About multimedia Streaming.. what are it needs and why does it require a different protocol?

The truth is,TCP/IP (using HTTP protocol) is well suited for transfer of static Web pages. TCP enforces reliability without regard to timelines. Therefore, it is not suited for use in time based multimedia programs that require timely delivery and more rigorous error detection. Another protocol needed to be invented. The standard became RTP/RTSP (first invented by Real Networks), which became the precursor to the current video streaming standards. More about that later.

When you are done, click here to go to the next Lesson/Activity

In Lessons-6207. Both comments and pings are currently closed.