Transcript Chapter 1 Information Technology: Principles, Practices

Chapter 3
Internet and World Wide Web
1
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/
2
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
3
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
4
ARPANET
is Born
1968
Hypertext
Invented
1965
Packet
Switching
Invented
1964
First Vast
Computer
Network
Envisioned
1962
1962
TCP/IP
Created
1972
Internet Named
TCP/IP Used
1984
WWW
Created
1989
Mosaic
Created
1993
Age of
eCommerce
Begins
1995
1995
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
6
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
7
Vinton Cerf
• Summary: Vinton Cerf is codesigner (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
8
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
9
Structure of the Internet
10
Structure of the Internet
11
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?
12
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.
13
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.
14
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.”
15
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)
16
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.
17
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
Internet
WWW
18
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
19
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
20
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
21
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
22
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.
23
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.
24
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.
25
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.
26
Internet Addresses
27
URLs
• Uniform Resource Locator
• Human-readable WWW Address
• Examples:
– http://www.cs.siena.edu
– ftp://ftp.cs.rpi.edu
– [email protected]
• Includes email addresses and newsgroups
28
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)
29
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.
32
IP Addresses
• Numeric Internet Address
• Part of the TCP/IP Protocol
• URLs are translated into IP Addresses by DNS
Servers
• DNS  Domain Name System
33
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
34
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.
35
Internet Addresses
Internet Addresses
Addresses on Host Computers
(Continued)
37
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.
38
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
39
Important Milestones
September 2002
Netsizer.com – from Telcordia
40
Growth of Internet Hosts *
Sept. 1969 - Sept. 2002
250,000,000
Sept. 1, 2002
No. of Hosts
200,000,000
150,000,000
100,000,000
Dot-Com Bust Begins
50,000,000
9/
69
01
/7
1
01
/7
3
01
/7
4
01
/7
6
01
/7
9
08
/8
1
08
/8
3
10
/8
5
11
/8
6
07
/8
8
01
/8
9
10
/8
9
01
/9
1
10
/9
1
04
/9
2
10
/9
2
04
/9
3
10
/9
3
07
/9
4
01
/9
5
01
/9
6
01
/9
7
01
/9
8
01
/9
9
01
/0
1
08
/0
2
0
Time Period
Chart by William F. Slater, III
The Internet was not known as "The Internet" until January 1984, at which time
there were 1000 hosts that were all converted over to using TCP/IP.
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!
42
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.
Siena College
Roger Bacon
Ken Swarner’s
office
www
(ares)
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?
44
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
45
Internet connections
•
•
•
MONTHLY FEE
DOWNSTREAM
UPSTREAM
Dial-up $10-30/month
DSL $30-40/month
Cable $40-50/month
RR
Hom e
Office
RR Pro RR Corporate RR Enterprise RR Prem ier
$79.95 $199.95
$249.95
$399.95
$399.95
2 Mbps
2 Mbps
3 Mbps
4 Mbps
1.5 Mbps
384 KBPS 768 Kbps
768 Kbps
1 Mbps
1.5 Mbps
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
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
49
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
50
Domain Names
51
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.
Domain Name Table
…
www.breimer.org  204.168.0.207
IP Address:
204.168.0.207
ISP
…
My computer
DNS
Authority
Multi-tiered
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.
54
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
55
Other hosting options
• Free services
– Angelfire
– Geocities
• Cheap services
– Roadrunner
– AOL
• Piggy-backing
– College
– Company
56