How the Web Works

When individual users get on the Internet they are actually connecting to the World Wide Web (WWW or web), sometime used synonymously with Internet, the web is a system of interlinked documents located on the part of the Internet that is available to the public.

Networks

The Internet consists of the entire global network of computers. This network is made works on theclient/server model. Client/Server can describe a relationship between two computer programs. The clientcomputer requests some type of service (such as a file or database access) from the server. The servercomputer fulfills the request and transmits the results to the client over a network.

Peer-to-peer-network is a type of decentralized network where each computer on the network (peers) acts both as a client and server.

When a client computer makes a request to the server, the requested files are copied from the server to the client, this is known as downloading. The process of the page appearing in the web browser is called loading.s

Data on a network travels through what is called communication circuits. The amount of data that can be transmitted at any one time through a communication circuit is called bandwidth. Bandwidth is measured inbits.

Bits and Bytes – Computers are based on a Binary is a numbering system, consisting of two unique numbers 0 and 1. A bit is a single binary digit. A byte is made up of 8 bits.

In order to connect to any type of network a computer must have a network interface card (NIC) or network card. A cable is then run from the NIC to the server or another client computer.

In a large network a special device is used to connect the computers on the network.
There are several different types of devices used to complete this task each one has special capabilities.

  • Hubs allow for multiple computers to talk to each other all at the same time.
  • Switches are like traffic lights allowing one computer to talk another, one at a time.
  •  Routers are like switches, but also direct the data allowing for Internet connections.

There are different types of networks:

  • Local Area Network (LAN)
  • Wide Area Network (WAN)

Furthermore there are different types of network connections:

  • Cable connection
  • Wireless connection

Connecting to the Internet

In order to connect to the Internet one must first obtain an Internet service provider (ISP), who allows for access to the  network access points (NAPs) to the Internet.

In order for a computer to transmit data over a telephone or cable line, a device known as a modem is required. The modem allows for a connection to your ISP.

Go Wireless! In order to access the Internet wirelessly, a WLAN (wireless LAN) card is required and can be used in place of a NIC card. Note that a WLAN card requires that the computer accessing the network be within the range of a wireless access point.

Once connect to the Internet one can access the World Wide Web or web. The web is the part of the Internetthat is available to the public and is made up of a network of connected computers called web severs.

The web is made up of hypertext documents. Hypertext refers to text displayed on an electronic device with a reference (hyperlink) to another document that can be instantly accessed. The concept of linked hypertext is the defining foundation for the web and was conceived by Tim Berners-Lee at the CERN, the European Organization for Nuclear Research.

In 1989, Berners-Lee would make available on the Internet, the code for a hypertext server program. This program would later be installed on web (hypertext) servers and used to store files in hypertext markup language (HTML).

Since that time HTML has become the standard language for developing hypertext documents or web pages. A website is a group of related web pages, which all reside on the same web server. The homepage is the first page that displays when visiting a specific website.

In order to access information on a web server, Berners-Lee developed the Hypertext Transfer Protocol (HTTP) a set of rules for exchanging files such as text, graphics/images, sound, video and other media via the web.

When a client computer sends a request it must identify a resource on the Internet or uniform resource identifier (URI) The URI is made up of two distinct parts the universal resource name (URN) and theuniversal resource locator (URL). Think of it like this, the URI is specific persons information in a contact book, the URN is the person’s name while the URL is the person’s address.

Thus, just as people have addresses to locate their homes, each web server on the Internet is given their ownInternet Protocol (IP) address. An IP address is made up of a set of four groups of numbers called octets.

Since it is difficult to remember large groups of numbers the Domain Name System (DNS) was established and Associates text-based domain names with numeric IP address assigned to a device.

top-level domain (TLD) refers to the last part of a domain name. A TLD refers to the top-level in the DNS hierarchy and identifies the website through association. The ICANN directs the designated organizations in the management of each separate TLD registry. Common TLD’s include:

  • .com
  • .org
  • .net
  • .gov
  • .edu
  • .us (or other country code)

Therefore in order to access the Internet one must know the URL of the web page or site you are trying to access. The URL consists of the specific protocols for communication transfer, the name of the web server the data is located on, and the domain name or IP Address. One example is http://wwww.getcereativetoday.com , HTTP is the protocol, www is the web server and getcreativetoday.comis the domain name.

Web Browsers

Web pages are documents written in HTML. HTML is made elements (tags) and attributes that define how and what content a web page displays. In order to display this content a special software called a web browseris required. A web browser translates HTML coding to display in a meaningful manner, with text, graphics,hyperlinks and more.

The Internet

We use it everyday to connect to friends and family, pay bills, submit assignments, watch movies, and look up the whether or just goof off. I’m speaking of course about the Internet. So, much of our daily lives takes place on the Internet it is sometimes difficult to imagine a time without it, but have you ever wondered what exactly is the Internet and when did it get started?

In simple terms the Internet is an interconnected network of computers on a global scale, which facilitate the sharing or exchange of information among its’ users.

Invention of the Internet

Although many of us could date the inception of the Internet back to the 1990’s its’ begging’s date back much further. No one group or person developed the Internet, but instead there were many organizations that help develop the methods and technologies that help lead way to the Internet we know and use today.

The foundations of the Internet began in the late 1950’s.  At the time computers only worked by batch processing, this meant that the computer could only work on one task at a time. That task had to be programmed on to punch cards. Then the system operator would take a “batch” of the programmed cards and feed them into the computer. The computer would run each task in order as they were fed in completing one at a time.

At this time in computer history, in order to store a lot of information, computers were huge and had to be stored in cooled rooms. Thus, programmers had to work remotely sending their work to the system operators to input into the computer; the indirectness of this method, lead to a lot of manual labor and bugs in the program.

In 1957, programmers had enough; a remote connection to the computer was installed, allowing direct access. Since multiple programmers now had access to the computer the concept of time-sharing was established, meaning that multiple users would share the processing power of the computer.

During the same time the United States developed the Defense Advance Research Project Agency (DARPA) in order to assure Americas lead in technology. People, only transferred information at the time.

What is Data – Data are distinct pieces of information formatted in special ways. A computer program is a collection of instructions for manipulating data. The term data is most often used to describe binary information. Binary is a numbering system, which computers are based on, and consist of two unique numbers 0 and 1.

Thus DARPA’s first priority was to establish a large-scale network of computers to execrate the transfer of information and to avoid the duplication of already existing research. This scientific network would be known as ARPANET.

At the same time three other networks were being developed

  • RAND – a military network by the RAND Corporation in the US.
  • NPL – a commercial network by the National Physical Laboratory in England
  • CYCLADES – a scientific network by the Institut de Recherche d’Informatique et d’Automatique in France.

These networks along with the ARPANET would build the foundation for what would be come the Internet.

ARPANET began in 1969 connecting four computers, one at the University of California in Los Angeles, SRI International, The University of California at Santa Barbara and the University of Utah.

In order for computers to talk to each other on a network they need to follow the same set of communication rules in order to move files between computers, these rules are known as transfer protocols. The first set of protocols established was the Network Control Protocol (NCP).  Soon, the NCP was replaced by theTransmission Control Protocol (TCP). The main feature of the TCP was the verification of information from one computer to the other, verifying where it was coming from and that it was received by the correct system. The TCP also included the rules to join and end connections on the network.

In order to send a lot of information at one time through a network, information had to be broken into smallerdata packets (small chunks of information) allowing them to move through the connection faster. The data packets would then be recompiled on the receiving computer. This method of sending data on a network is called packet switching. The NPL in England, used packet switching to the fullest since being a commercial network it had a higher rate of network traffic than the other networks.

DARPA’s research was taking place during the height of the cold war, thus one its main priorities was to ensure to transfer of information in the event of an atomic attack. At the time information was sent by radio waves, which render useless in such an attack, thus a distributive network had to be established.

The French network, CYCLADES had a smaller budget than all other networks, therefore its primary focus was on the connection to other networks. To increase efficiency on their limited network, CYCLADES developed a protocol instructing computers on the network were not to intervene with the data being sent and only to work as a transfer node until the data reached the destination computer. These protocols were built onto the computer’s hardware allow for a more direct connection.

Due to the incompatibilities of other networks the CYCLADES protocols quickly inspired a new way of connecting. With the advances in network communication the phone companies offered their services by developing their own X.25 protocol, which allowed for communication access through their service for a monthly fee.

With so many networks establishing connections around the world, it wasn’t long before the International Organization for Standardization (ISO) felt the need to establish some standard methods of communication. They began by developing the Open System Interconnection (OSI), which allowed for communication to be standardized from its end. This eliminated the need for computer to access a connection through gateways, as established by DARPA’s TCP.

Who is ISO? The International Organization for Standardization (ISO) was established in 1947 with delegates from 25 countries. The organization’s goal was to develop international coordination and unification of industrial standards. Today there are 163 countries apart of the ISO. For more information see http://www.iso.org/

Using the OSI model, the TCP gave way to the TCP/IP protocol. The Internet Protocol (IP) is the rules for directing individual data packets. In combination the TCP/IP set of protocols includes a tool to simplify file transfer and to access computers that are not on the users primary network over, what we consider, the Internet. The TCP/IP would be the standard ensuring compatibility between networks.

In the 1980’s ARAPANET had more than 200 networks, with so much traffic and users, the network was divided into two. The Military Network (MILNET) would continue to be a secure network only for military research. While the Computer Science Network (CSNET) would be used by educational and research institutions. The CSNET would later merge with the National Science Foundation Network (NSFnet) to form one network that could care more traffic than had been previously. By the late 1980’s many TCP/IP networks had merged together creating the global network we think of today as the Internet.

Getting on the Internet

The 1980’s gave birth of the personal computer; thanks to advances in technology computers were now smaller, more powerful and affordable. Large companies and organizations would invest in computers and construct intranets. An intranet is a network of computers on a restricted network. This meant for example, company A had a network of computers that could only talk to computers at company A. While company B had computers who could talk to computers at company B. At this time there was no way for company A and company B computers to talk to each other.

Ray Tomlinson a researcher at ARPANET, in 1972 developed a program that could send and receive messages over a network, laying the foundation for email (electronic mail). At the time mailing listsnewsgroups(posting areas), and bulletin boards became a common method of sending information between users.

The Internet at the time was reserved for education and research. The NSF, who was overseeing the development Internet at the time, prohibited commercial use of the Internet. However, growing demand for better communication between commercial organizations, the NSF, in 1989, permitted two commercial email services allowing for limited Internet access. Finally company A could talk to company B via the Internet (an outside network).

In 1991, the NSF would finally lift the commercial ban on the Internet. To connect to the Internet the NSF developed network access points (NAPs), which would be operated by for four telecommunication companies, who sell access to large organizations called Internet service provides (ISP). Furthermore the ISP would provide access to business and individuals.

World Wide Web

The Internet consists of the entire global network of computers. When individual users get on the Internet they are actually connecting to the World Wide Web (WWW or web), sometime used synonymously with Internet, the web is a system of interlinked documents located on the part of the Internet that is available to the public.

Who runs the Internet

Since it’s conception in the late 1950’s many organizations played a part in the development of the Internet. Still today there is no central governing organization that oversees the Internet.

Instead there are several entities that work together to establish standards for the Internet. These organizations include:

  • Internet Architecture Board (IAB)
  • Internet Corporation for Assigned Number and Names (ICANN)
  • Internet Engineering Task Force (IETF)
  • Internet Society (ISOC)
  • World Intellectual Property Organization (WIPO)
  • World Wide Web Consortium (W3C)

The most recognizable of these organizations I the W3C, which develops recommendations (standards and guidelines) and prototype technologies related to the web. The four major areas which the W3C focus on include:

  • Web Architecture
  • User Interface
  • Technology and Society
  • Web Accessibility Initiative (WAI)

Web Accessibility

Section 508 of the Rehabilitation Act, requires that government agencies must give individuals with disabilities access to information technology that is comparable to the access available to others. The WAI, work towards creating best practices and techniques for ensuring the accessibility of content on the web.