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Chapter 3

Internet and World Wide Web

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What is the Internet?

• The largest network of networks in the world.• Uses TCP/IP protocols and packet switching .• Runs on any communication substrate.

• http://som.csudh.edu/cis/lpress/history/arpamaps/

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Brief History of the Internet

• 1968 - DARPA (Defense Advanced Research Projects Agency) contracts with BBN (Bolt, Beranek & Newman) to create ARPAnet (Advanced Research Projects Agency)

• 1970 - First five nodes: – UCLA– Stanford– UC Santa Barbara– U of Utah, and – BBN

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Brief History of the Internet

• 1974 - TCP protocol invented by Vint Cerf• 1984 – On January 1, the Internet with its 1000

hosts converts en masse to using TCP/IP for its messaging

• 1968 is really the “birth” of the Internet• 1984 is really the “high-school graduation” of

the Internet

1962 1995

WWWCreated

1989

MosaicCreated

1993

Packet Switching Invented

1964

First Vast ComputerNetwork

Envisioned1962

ARPANET is Born

1968

TCP/IPCreated

1972

Internet Named TCP/IP Used

1984

HypertextInvented

1965

Age ofeCommerce

Begins1995

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Claude Shannon

• The Father of Modern Information Theory

• Created the idea that all information could be represented using 1s and 0s. Called these fundamental units BITS.

• Won a Nobel prize for his master’s thesis in 1936

Source: http://www.research.att.com/~njas/doc/ces5.html

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Vannevar Bush

• Summary: Vannevar Bush established the U.S. military/university research partnership that later developed the ARPANET.

• He also wrote the first visionary description of the potential use for information technology, inspiring many of the Internet's creators.

Source: Livinginternet.com

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Vinton Cerf

• Summary: Vinton Cerf is co-designer (with Bob Kahn) of the TCP/IP networking protocol.

• Worked for DARPA, projects include d– the Packet Radio Net (PRNET),

and – the Packet Satellite Network

(SATNET).

Source: Livinginternet.com

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Tim Berners-Lee

• The inventor of HTML. • Now works for Laboratory for

Computer Science (LCS)at the Massachusetts Institute of Technology (MIT).

• Directs the W3 Consortium, an open forum of companies and organizations with the mission to realize the full potential of the Web.

Source: w3c.org

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Structure of the Internet

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Structure of the Internet

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The Internet vs. World Wide Web

• What EXACTLY is the difference between the Internet and the World Wide Web?

• Why is it important to know the difference?

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The Internet

• Computers can be connected in a variety of different ways.– Ethernet, Token-ring, Wireless, Ports (Serial,

Parallel, USB). These are all communication subtrates.

• Two or more connected computers form a Network– The CS Dept. has its own Ethernet Network

• Different types of networks can be connected– via bridges, gateways, etc.

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The Internet

• Two or more connected networks can be called an inter-network– Inter-networks can obviously be connected

• At some point in history, inter-networks became connected across the entire USA– Eventually, inter-networks became

connected across the entire world• The entire world-wide collection of connected

networks became known as The Internet.

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The Internet

Most experts in the “Network World” think of The Internet as both– The physical infrastructure (wires, routers,

hubs, switches, satellites, optical cables, receivers, transmitters, etc.) that form the inter-connections.

– And, the actual collection of computers (and devices) that are “inter-connected.”

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The World Wide Web (WWW)

• Most experts think of The WWW as– data that is accessible via a URL

• (narrow definition)

– All the data and services that are widely available via The Internet

• (general definition)

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The World Wide Web (WWW)

• Thus, The Internet is the physical hardware that makes the connections possible and

• The World Wide Web is the content and services that are widely available over this massive collection of connected computers.

• Important Note: – Some companies use the Internet to share

information, but this information is only accessible through proprietary protocols,

– Since, it is NOT widely available, it is not really part of the WWW.

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The World Wide Web (WWW)

• While the two terms are somewhat synonymous to the non-expert,

• You should be aware of the difference between The Internet and the WWW

InternetWWW

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The World Wide Web (WWW)

Examples: Content & High-level Protocols• Content: WebPages

– Hypertext Transfer Protocol (http)– URL (Universal Resource Locator)

• Content: Data Files & Programs– File Transfer Protocol (ftp)

• Content: Music & Videos– Gnutella Protocol

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The World Wide Web (WWW)

More examples• Content: Email

– SMTP (Simple Mail Transport Protocol) – IMAP (Internet Message Access Protocol) – POP (Post-Office Protocol) – DNS (Domain Name System) – MIME (Multipurpose Internet Mail Extensions)

• Content: Peer to Peer messaging– AOL IM Protocol– MSN Messenger Protocol

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The Internet

Examples: Hardware & Low-Level Protocols• Hardware

– Computer, Ethernet card– Communication Substrate:

CAT-5 cable, fiber optic cable– Router, Hub, Switch, Bridge, Gateway

• Low-Level Protocols/ Concepts– TCP/IP (Transmission Control Protocol/Internet

Protocol)– Packet Switching

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Capabilities of the Internet & WWW

• Web Pages• E-mail• Mailing Lists• Newsgroups

(Usenet)• Chat, IRC, AOL IM• Search Engines

• FTP• Telnet (SSH)• Telephony• Database Access• Application Access• E-Commerce• Streaming

Video/Audio

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WWW Concepts

– Authority• Vertical Portal or Vortal: A Web site that

specializes in providing information related to a particular industry such as automobiles, healthcare, or investments.

– Hub or Gateway• Horizontal Portal: Provides services and

links to Web sites of interest to a wide variety of users.

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WWW Concepts

• Webcasting: The prearranged delivery, or push, of information of interest to a user’s desktop automatically.– Pull:

• To get something from a Web site by clicking on a link or entering a URL.

– Push:• The capability of a Web site for automatic

Internet delivery of information, including software updates, to a user’s desktop.

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The Internet Community

• Internet Users

• Internet Service Providers (ISPs)

• Application Service Providers (ASPs): Companies that develop, install, and operate (or host) an information technology application

• Content Providers: Individuals or companies that furnish the information available on the Internet.

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The Internet Community

• Internet Support Agencies– Internet Corp. for Assigned Names and Numbers

(ICANN): The nonprofit corporation responsible for • the IP address space allocation• protocol parameter assignment• domain name system management, and • root server system management.

– Internet Engineering Task Force (IETF): A large international community of network designers, operators, vendors, and researchers concerned with

• the evolution of Internet architecture and • the smooth operation of the Internet.

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Internet Addresses

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URLs

• Uniform Resource Locator• Human-readable WWW Address• Examples:

– http://www.cs.siena.edu– ftp://ftp.cs.rpi.edu– ebreimer@siena.edu

• Includes email addresses and newsgroups

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URLs

• Example: http://www.cs.siena.edu– http is the protocol– www is the host name (server name)– cs.siena.edu is the domain (network

address)• edu is the top level domain• siena is essentially Siena College’s

network• cs is the CS Dept Network (sub-set of

Siena)

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Internet Addresses

• Domain Name System (DNS): Computers have numeric addresses consisting of strings of numbers known as their Internet protocol (or IP) address.

• Domain Name: The familiar, easy-to-remember names for computers on the Internet that correlate to assigned IP addresses.

• Uniform Resource Locator (URL): Like a Street Address for the WWW.

• Registry: A regional organization that allocates Internet addresses to requestors in that region.

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IP Addresses

• Numeric Internet Address• Part of the TCP/IP Protocol• URLs are translated into IP Addresses by DNS

Servers• DNS Domain Name System

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IP Addresses

• Example: 64.236.24.4• 4 numbers separated by decimal points• 64 is the top level network• 4 is a specific computer (host or server)• Lets do an nslookup on an IP Address

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Internet Addresses

• Registrars: Organizations delegated to accept and process Internet address applications and submit approval applications to the regional registrar.

• Root Servers: One of 13 special computers distributed around the world that maintain the Internet addresses for all global and country registries.

Internet Addresses

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Internet AddressesAddresses on Host Computers (Continued)

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HTML

• Hypertext Markup Language (HTML): – A set of commands that specifies the

position, size, and color of text, the location of graphic information, and the incorporation of sound and video.

– HTML commands also identify the words or images that will serve as hyperlinks to other documents.

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Internet Growth Trends

• 1977: 111 hosts on Internet• 1981: 213 hosts• 1983: 562 hosts• 1984: 1,000 hosts• 1986: 5,000 hosts• 1987: 10,000 hosts• 1989: 100,000 hosts• 1992: 1,000,000 hosts• 2001: 150 – 175 million hosts• 2002: over 200 million hosts• By 2010, about 80% of the planet will be on the Internet

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Important Milestones September 2002

Netsizer.com – from Telcordia

Growth of Internet Hosts *Sept. 1969 - Sept. 2002

0

50,000,000

100,000,000

150,000,000

200,000,000

250,000,000

Time Period

No

. of

Ho

sts

The Internet was not known as "The Internet" until January 1984, at which timethere were 1000 hosts that were all converted over to using TCP/IP.

Chart by William F. Slater, III

Sept. 1, 2002

Dot-Com Bust Begins

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Internet’s Growth

• To get a market of 50 Million People Participating:– Radio took 38 years – TV took 13 years– Once it was open to the General Public, The

Internet made it to the 50 million person audience mark in just 4 years!

Web Servers

• Rough map of the world as seen from our web server

• Your web server is only as fast as your slowest network bottleneck.

Ken Swarner’s office

www (ares)

Roger Bacon

Siena College

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Web Servers

• How can I set up my own web server.

1. First, you need to get software

2. Second, you need a pretty good internet connection

3. Third, you need to register a domain name

4. Finally, you need to actually make some webpages

• How much does this all cost?• How hard is it?

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Web server software

• Apache (its free and its very good)– UNIX and Windows versions– Problems:– Not super easy to setup or configure– If you are not already a nerd, you’ll

probably need a lot of time.• Microsoft makes several different servers

– Somewhat easier to setup than Apache

Internet connections

• Dial-up $10-30/month• DSL $30-40/month• Cable $40-50/month

RRHome Office

MONTHLY FEE $79.95 $199.95 $249.95 $399.95 $399.95

DOWNSTREAM 2 Mbps 2 Mbps 3 Mbps 4 Mbps 1.5 Mbps

UPSTREAM 384 KBPS 768 Kbps 768 Kbps 1 Mbps 1.5 Mbps

RR PremierRR Pro RR Corporate RR Enterprise

Internet connections• T1

– $250 to $1000/month– 1-3 Mbps

• T3– $3000 to $15,000/month– 3-45 Mbps

Internet connections

• OC-3 – $20,000 to $50,000/month – 150+ Mbps

• OC-12 – Over $500,000 year – 600+ Mbps

• OC-48 – Good luck finding one– used internally by companies like Sprint

who sell the above connections– 2400+ Mbps

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Internet Connections

• Siena used to have– 3 dedicated T-1 lines (bundled?)– about 3 Mbps

• Siena now has– RoadRunner Premier (perhaps two separate

connections)– about 6 Mbps (just a guess

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Internet Connections

• RPI (3 years ago)– Equivalent of 2 dedicated T-3’s – 50+ Mbps– 10-times Siena’s bandwidth.

• Now, they may have an OC-3– 150+Mbps– 30-times Siena’s bandwidth

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Domain Names

Domain Names

• To get the Internet to recognize your domain you have to get your ISP to add your domain to its Domain Name Server

• This will have a cascading effect and eventually your domain can be reached.

My computer

IP Address:204.168.0.207

ISP

Domain Name Table…www.breimer.org 204.168.0.207…

DNSAuthority

Multi-tiered

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Domain Names & Hosting

• Companies that register your domain name are often ISP’s and

• Will set you up with:– A domain name– A dedicated IP address– And, they make sure you get added to the

right tables– Associates your IP address with your

domain.

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On-site vs. Off-site

• Most hosting companies have their own servers and will provide off-site hosting– Off-site means they host your stuff on their

servers– You don’t have your own servers on-site

• Most ISP can set you up on-site if you have– Your own server– Your own support personal– Your own infrastructure

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Other hosting options

• Free services– Angelfire– Geocities

• Cheap services– Roadrunner– AOL

• Piggy-backing– College– Company