COM 205
Multimedia Applications
St. Joseph’s College
Fall 2004
7/24/2016
Chapter 12
The Internet and How It Works
7/24/2016
HISTORY
A. ARPANET
• 1. The Internet was created in 1969 by the
Advanced Research Projects Agency (ARPA).
– a)ARPA was part of the U.S. Department of Defense.
– b) The ARPANET grew as it networked universities,
military sites, and government agencies.
• 2.
In 1985, National Science Foundation (NSF)
used ARPANET to connect supercomputers and
computer science centers.
– a)Management of the ARPANET officially passed to the
NSF in 1989.
• 3.
Commercial use of the Internet began in 1992.
Internetworking
Networking basics
• 1.
Two or more computers connected to each other
make a network.
• 2.
A local network is called a local area network
(LAN).
• 3.
Distant LANs can be connected via phone lines
or another medium to form a wide area network
(WAN).
• 4.
LANs, WANs, and individual computers can
also connect to the Internet through a server.
a)A server is permanently connected to the Internet through a
high-bandwidth physical connection
Internetworking
• TCP/IP is the protocol used for
communicating on the Internet
– TCP is Transmission Control Protocol
– IP is the Internet Protocol
• In 1983 the Domain Name System
(DNS) was established to assign
names to computers which were
linked to the Internet.
Internet Addresses
• 1. Address syntax
• a) Internet addresses use the following syntax:
[protocol]://[domain
name]/[path]/[file name]
( http://www.sjcny.edu) for example
• b) The server directory path and file name are
often left off.
• c) The protocol usually does not need to be typed.
• d) The protocol is also often hidden, such as
• (1)
mailto
• (2)
news
Internet Addresses
• 2.
Top-level domains (TLDs)
– a) The current Domain Name System (DNS) was
developed in 1983.
– b) TLDs were established for various categories.
– c) The TLD is part of the domain name, such as
• (1)
.com
• (2)
.net
• (3)
.gov
• (4)
.mil
• (5)
• (6)
. edu
Two-letter country codes
Domain Name System ( DNS)
• In 1998 (ICANN) Internet Corporation
for Assigned Names and Numbers
was set up to oversee the DNS.
• In 2000, ICANN approved seven new
TLDs:
• aero
info
pro
• biz
museum
• coop
name
Domain Name System ( DNS)
• Other names are under discussion
and may be added in the future:
• web
• arts
• shop
• firm
• nom
• rec
IP Addresses and Data Packets
• A The Internet transmits data using the
Transmission Control Protocol (TCP).
• (1)
Data is broken up into packets.
• B The Internet Protocol (IP) transmits the
packets.
• (1) Packets can travel along various paths and are
reassembled at the receiving end.
• (2) Destinations are identified by numeric IP
addresses such as: 140.174.162.10
• (3)
Domain name servers look up these addresses.
Connections
• 1.
To connect to the Internet, a computer or network
needs
– a) A data connection to a server
• (1) The data connection can be wireless or a
land line.
• (2)
You usually need an account with the server.
• (3) Most people access a server through an
Internet service provider (ISP).
– b) TCP/IP software
• (1) Your operating system may need to be
configured to connect to the server and use
TCP/IP software.
Connections
• c)
Internet software includes
– (1)
E-mail programs
– (2)
Web browsers
– (3)
FTP software
– (4)
News readers
• d)
ISP ( Internet Service Providers) software
– PPP - (Point to Point) for dialing up
– TCP/IP for sending and receiving
– POP (Point of Presence) - local telephone number
Bandwidth Bottleneck
• 1. Bandwidth is how much data, you can send
from one computer to another in a given unit of
time ( See p. 337)
• 2. The bandwidth bottleneck
– a) Bandwidth is measured in bits per second (bps).
– b) Available bandwidth greatly affects how a person
can use the Internet.
– c) Users with slow connections will have a difficult
time using multimedia over the Internet.
Bandwidth Bottleneck
• d)
To accommodate low bandwidth users
• (1)
Compress data when possible.
• (2)
Take advantage of the browser’s cache.
• (3)
Design for download efficiency- don’t overdo
animation, colors, etc.
• (4)
Design alternate sites for low- and high-bandwidth
users.
• (5)
Consider using streaming technology.
Internet Services
• 1.
Services include http, ftp, telnet, Usenet, SMTP,
IRC, and others.
– a)Some services, such as Gopher, are not commonly used.
• 2. Multipurpose Internet Mail Extensions (MIME)-types
– a)Files used online must conform to Internet protocols.
– b)Data types are identified using MIME-types.
– c) File types must be recognized by servers to be used on the
Internet.
The World Wide Web and HTML
• A. Web history
• 1.
Tim Berners-Lee of CERN (the European
Particle Physics Laboratory) developed the Web’s
hypertext system in 1989.
– a)The Hypertext Transfer Protocol (HTTP) was designed as a
means for sharing documents over the Internet.
– b)The Hypertext Markup Language (HTML) is the markup
language of the Web.
– c) Cross-platform compatibility was a design goal.
HTTP
• The Hypertext Transfer Protocol ( HTTP)
provided rules for a simple transaction:
• 1. Establishing a connection
• 2. Requesting that a document be sent
• 3. Sending a document
• 4. Closing the connection
HTML
• The HTTP protocol also required a
simple document format called HTML
(Hypertext Markup Language) for
presenting text and graphics
• The HTML document can contain
hotlinks which a user can click to
jump to another location
Dynamic Web pages and XML
• 1. Advanced tools can be used to make a Web page
dynamic.
– a)Dynamic technologies include
• (1)
Cold Fusion (CFM)
• (2)
Hypertext Preprocessor (PHP)
• (3)
Active Server Pages (ASP)
• (4)
Java Script and Java Applets
– b)Dynamic pages work in conjunction with database
applications to look up data.
(XML) eXtensible Markup
Language
– a) XML goes beyond HTML and is the next
step in developing web pages.
– b) This markup language allows developers to
define their own styles and elements.
– c) It allows you to create your own tags to
describe what the data means
– d) Whether or not XML is the future of Web
design is still somewhat questionable.
• Check www.xml.org and www.xml.com
Multimedia on the WEB
• Developers need to understand how
to create and edit elements of
multimedia and also how to deliver it
for HTML browsers
• The number of new users of the web
will create a greater need for high
quality, compelling content, and
reasonably quick presentations
Project Idea
•
•
•
•
Visit these web sites
http://www.navy.com/
http://www.sigov.si/
http://www.w3.org/MarkUp/Guide/Style.
html
– For each address, answer the following
questions:
– What is the title of the Web page?
– Briefly describe the content of the Web
page.
– What is unique about the URL?