The Internet and the World
Infrastructure for Electronic
What is the Internet?
Internet – Intranet - Extranet
Web-based Client/server Computing
What is the Internet?
Internet is a collection of computer networks
All computers on the Internet must use same
network & transport protocols TCP/IP
Who runs the Internet
No one runs the internet
Volunteer organizations suggest changes or
Internet Assigned Number Authority
Internet Research Task Force
Network Information Centers
Internet Architecture Board
No single owner
Backbone is maintained by a few
Everyone maintains their piece of the
network - whether a university,
business, or a single user at home
When you get connected the Internet
grows by one
Failure of one network will not halt
A local area network (LAN) is a network of computers
A wide area network (WAN) is a network of
computers connected over a great distance.
Circuit switching is used in telephone communication.
The Internet uses packet switching
• Files are broken down into small pieces (called
packets) that are labeled with their origin,
sequence, and destination addresses.
When packets leave a network to travel on the
Internet, they are translated into a standard format
by the router.
Routers and the telecommunication lines connecting
them are referred to as ‘the Internet backbone’.
The TCP/IP Protocol
The Transmission Control Protocol (TCP) and the
Internet Protocol (IP) are the two protocols that
support the Internet operation.
TCP controls the assembly of a message into smaller
packets before it is transmitted over the Internet.
The IP protocol includes rules for routing individual
data packets from their source to their destination.
Internet addresses are based on a 32-bit
number called an IP address.
IP addresses appear as a series of up to four
separate numbers delineated by a period.
An address such as 220.127.116.11 uniquely
identifies a computer connected to the
To make the numbering system easier to use, an
alternative addressing method that uses words
An address, such as www.course.com, is called a
The last part of a domain name (i.e., ‘.com’) is
the most general identifier in the name and is
called a ‘top-level domain’ (TLD).
Top-level Domain Names
Internet Services Protocols
The Internet provides a variety of services
to users known as ‘application services’.
Application services include Web page
delivery, network management tools,
remote login, file transmission, electronic
mail, and directory services.
SMTP, POP, and IMAP
E-mail is sent across the Internet is managed
and stored by mail servers.
Simple Mail Transfer Protocol (SMTP) is the
standard for e-mail client program.
Post Office Protocol (POP) is the standard for
e-mail server program.
The Interactive Mail Access Protocol (IMAP) is
a newer e-mail protocol.
How Does The Internet
Link (ISP, LAN)
Connections (Modem, ISDN, etc.)
The client is the Web browser, or Web browser and
computer, that requests Web pages and services from a
The server is the Web server software, or Web server and
software and computer, that fills client requests for Web
pages and services.
Requests & Parameters
Response & Results
Web Clients and Web Servers
Three-Tier and N-Tier Client-
Internet – Intranet - Extranet
The Internet is a network of networks composed of
thousands of LANs and WANs.
An intranet is a private Internet owned by a company.
An extranet is an extended intranet, providing for
A firewall is a device, or set of devices, designed to
protect a company's intranet from the Internet.
An intranet is a Web-based private network that
hosts Internet applications on a LAN.
Intranets are an extremely popular and low-cost way
to distribute corporate information.
The intranet infrastructure includes a TCP/IP
network, Web authoring software, Web server
hardware and software, Web clients, and a firewall
Intranets and Extranets
The most common connection options that ISPs
offer to the Internet are telephone, broadband,
leased-line, and wireless.
Bandwidth is the amount of data that can travel
through a communication line per unit of time.
Bandwidth can differ for data traveling to or from
The most common way to connect to an ISP is
through a modem connected to your local
telephone service provider.
POTS uses existing telephone lines and an analog
modem to provide a bandwidth of 28-56 Kbps.
ISDN uses the DSL protocol suite to offer
bandwidths between 128-256 Kbps.
Connections that operate at speeds of greater than
200 Kbps are called broadband services.
ADSL uses the DSL protocol to provide bandwidths
between 100-640 Kbps upstream and 1.5-9 Mbps
Cable modems provide transmission speeds between
300 Kbps-1 Mbps from the client to the server and a
downstream rate as high as 10 Mbps.
Satellite microwave transmissions handle internet
downloads at speeds around 500 Kbps.
Large firms can connect to an ISP using higher-
bandwidth connections that they can lease from
A ‘T1’ line operates at 1.544 Mbps and a ‘T3’ line
operates at 44.736 Mbps.
Many researchers and business managers see
great potential for wireless networks and the
devices connected to them.
The term m-commerce (mobile commerce) is
used to describe the kinds of resources people
might want to access using devices that have
1. Decide Business Objective (class #4)
2. Research Connection Options
3. Find an Internet Service Provider (ISP)
4. Contract for Internet Connection
5. Buy Hardware & Software
6. Obtain Domain Name
7. Turn on the Switch
Research Connection Options
Dedicated Connection Options
Find an Internet Service
ISP – is the company that you will contract
with for Internet connectivity
Basically two types
Commercial online services
ie AOL, MSN
Case study 6-2 the list
List of ISPs: thelist.internet.com
Buy Hardware & Software
Depending on level of internet
Modem, computer, server
for each service, router,
Client software for each
Server software for each
Security, transaction software
Obtain Domain Name
Domain Name – your identity on the internet--
for the internet it is how the info gets routed. (
easier than IP #)
.com Commercial users
.net Network providers
Domain Type .edu education
.gov U.S. gov.
.mil U.S. military
How to get a Domain Name
Case study 6-3
Domain Name System - WWW
WWW Folder or
Language Directory File or
Name of com - commercial
Computer Server edu - educational
gov - gevernment
Registered Domain Name (Name of Organization)
Internet service providers or a hosting service may
obtain the domain for you for a fee, but…
if their name is listed as administrative contact with
InterNIC, you may have trouble switching your
domain name to a new service
Make sure your name is listed as the administrative
contact with InterNIC
Determine who “owns” yours:
Turn on the Switch