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Technology Infrastructure: The Internet

and the World Wide Web

UNIT - I

Objectives

In this chapter, you will learn about:

• The origin, growth, and current structure of

the Internet

• How packet-switched networks are combined

to form the Internet

• How Internet protocols and Internet

addressing work

• The history and use of markup languages on

the Web, including SGML, HTML, and XML

The Internet and the World Wide

Web

• Computer network

• (^) Any technology that allows people to connect computers to each other

• The Internet

• (^) A large system of interconnected computer networks spanning the globe

• World Wide Web

• (^) A subset of computers on the Internet

Origins of the Internet

• Early 1960s

• (^) U.S. Department of Defense funded research to explore creating a worldwide network

• In 1969

• (^) Defense Department researchers connected four computers into a network called ARPANET

• Throughout the 1970s and 1980s

• (^) Academic researchers connected to ARPANET and contributed to its technological developments

Growth of the Internet

• In 1991, the NSF:

• (^) Eased restrictions on commercial Internet activity
• Began implementing plans to privatize the Internet

• Network access points (NAPs)

• (^) Basis of the new structure of the Internet

• Network access providers

• (^) Sell Internet access rights directly to larger customers and indirectly to smaller firms and individuals through ISPs

Emergence of the World Wide Web

(continued)

• Tim Berners-Lee developed code for a

hypertext server program

• Hypertext server:

• (^) Stores files written in the hypertext markup language
• (^) Lets other computers connect to it and read files

• Hypertext Markup Language (HTML)

• (^) Includes a set of codes (or tags) attached to text

Packet-Switched Networks

• Local area network (LAN)

• (^) Network of computers located close together

• Wide area networks (WANs)

• (^) Networks of computers connected over greater distances

• Circuit

• (^) Combination of telephone lines and closed switches that connect them to each other

Routing Packets

• Routing computers

• (^) Computers that decide how best to forward packets

• Routing algorithms

• (^) Rules contained in programs on router computers that determine the best path on which to send packets
• (^) Programs apply their routing algorithms to information they have stored in routing tables

TCP/IP

• TCP

• (^) Controls disassembly of a message or a file into packets before transmission over the Internet
• (^) Controls reassembly of packets into their original formats when they reach their destinations

• IP

• (^) Specifies addressing details for each packet

IP Addressing

• Internet Protocol version 4 (IPv4)

• (^) Uses a 32-bit number to identify computers connected to the Internet

• Base 2 (binary) number system

• (^) Used by computers to perform internal calculations

• Subnetting

• (^) Use of reserved private IP addresses within LANs and WANs to provide additional address space

Domain Names

• A domain name is a set of words assigned to

a specific IP address

• Top-level domain (or TLD)

• (^) Rightmost part of a domain name

• Internet Corporation for Assigned Names and

Numbers (ICANN)

• (^) Responsible for managing domain names and coordinating them with IP address registrars