Module 1: The Internet
Overview
It is essential today to become proficient in using Internet tools. The Internet brings democracy to
communications, provides an open medium to produce and consume services and products, and empowers us
by stimulating and encouraging innovation, participation, and imagination, anytime and anywhere. In this
module, we will discuss fundamental topics concerning the Internet.
First, we will provide some background about the Internet. Topics include defining the Internet, explaining the
history of the Internet, and discussing the different organizations that operate, manage, and set standards for
the Internet.
Next, we will talk about how the Internet works, focusing on the client/server model and the Internet
infrastructure. In addition, we will discuss how to transfer data via the Internet using Internet protocols and
addresses.
We will conclude this module by explaining the different technologies available for connecting to the Internet,
including wired and wireless.
Please note that many of the examples used in this course will focus on access to different servers, applications,
or other resources cited in the modules. When needed, specific instructions will be given for each division on
how to access the individual servers required for completing your coursework.
Report broken links or any other problems on this page.
Copyright © by University of Maryland University College .
Module 1: The Internet
Objectives
After completing this module, you should be able to:
outline the history of the Internet
describe the Internet's administrative and organizational entities
illustrate Internet protocols and addressing
describe Internet connectivity methodologies
Report broken links or any other problems on this page.
Copyright © by University of Maryland University College .
Module 1: The Internet
Commentary
Topics
1.
2.
3.
4.
What Is the Internet?
History of the Internet
Internet Organizations
How the Internet Works
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5.
6.
7.
8.
9.
The Internet Infrastructure
Internet Addressing
Internet Protocols
Connecting to the Internet
Internet Connection Technologies
What Is the Internet?
Contrary to popular belief, the Internet is not a physical entity to which one connects computers and computer
networks. Actually, it is a collection of computers and computer networks located all over the world. It is
important to note that throughout this course we will use the phrase "connected to the Internet." In reality,
however, a computer or computer network does not actually connect to the Internet; rather it becomes a
member of the Internet. To become a member of the Internet, the computer or computer network connects to
an existing member of the Internet by using a common set of Internet protocols.
The World Wide Web, or simply the Web, is only an element of the Internet. It is actually an overlay of the
Internet that enables us to access the information of the Internet in a graphical form. The Web uses the
Internet protocol of HTTP (Hypertext Transfer Protocol) to allow people to transmit data. HTTP is only one of
the languages "spoken" over the Internet. We will discuss this and other Internet protocols later in this module.
You can view the Internet in three ways:
as a group of resources available and accessible worldwide
as a community of people who exchange information and interact over the worldwide network
as a worldwide collection of computers and networks
In this section, we will focus on the last definition.
Two or more computers connected together and able to talk and understand each other constitute a computer
network. The Internet (with a capital I) is a proper noun and refers to the largest group of interconnected
networks in the world. The internet (with a small i) is a common noun and refers to any specific computer
network using TCP/IP protocols. There is only one Internet; however, there are many different types of
internets and private intranets. Companies and organizations can also choose to connect their internal networks
together, creating an "extranet."
Network managers make decisions regarding the size of the network, the topology, and how networks will be
connected to each other. Network sizes are LAN, MAN, and WAN. The Internet is the largest WAN in the world.
The function of an internet is essentially the same as any other communication medium, such as newspapers,
television, radio, the telephone system, or the postal system, in that each is made up of components that work
together to facilitate the dissemination of information.
An internet consists of:
hosts
a common communication protocol
a common address space
telecommunication links to connect the computers to the hosts
The same definition applies to the Internet (with a capital I).
Module 1: The Internet
A way to understand the Internet may be to compare it to a pre-existing network—a network used by the
creators of the Internet because of its proven method of using redundancy to increase communication: the
Public Switched Telephone Network (PSTN), also known as the United States' telephone system.
A telephone handset is the main device used for communication with other people connected to the telephone
system, which is normally located in one's home or office. The desktop computer is the main device most
people use to communicate with other people connected to the Internet, which, again, is normally located in
one's home or office. An illustration of the analogy appears below.
Telephone System
Communication device
telephone handset
The Internet
computer (host)
Communication protocol analog and digital signals
TCP/IP
Address space
telephone number
IP address
Communication media
copper wire, fiber optics, satellite, etc. copper wire, fiber optics, satellite, etc.
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History of the Internet
The U.S. Department of Defense (DOD) Advanced Research Projects Agency (ARPA) developed the ARPANET in
1969. ARPANET allowed four computers, located in California and Utah, to "talk" to each other. Because of the
Cold War and the fear of possible nuclear attacks, ARPANET was designed to allow continued communication if
one or more communication sites were destroyed. In the 1970s and 1980s, developers created the protocols
used to transfer, categorize, and search for information, using the ARPANET as a vehicle to transport the data.
Also during this time, the ARPANET was renamed the Internet. One of the most authoritative timelines of the
Internet can be seen at Hobbes' Internet Timeline.
The public was unaware of the Internet and its capabilities until after the development of the World Wide Web
(WWW) and the subsequent commercialization of the Internet. In 1989, Tim Berners-Lee and his co-workers at
the European Laboratory for Particle Physics (CERN) created another Internet protocol (HTTP), based on
hypertext and linking. This protocol allowed users to link directly from a document to another resource on the
Internet without issuing commands directly to their computers. Although this was a great improvement in
Internet accessibility, the system used a text-based browser.
Then, in 1992, Marc Andreessen released a Graphical User Interface (GUI) version of a browser called Mosaic
that allowed easier manipulation of Internet resources. The Mosaic browser became the browser known today
as Netscape. It is interesting to note that Microsoft founder Bill Gates stated in a 1996 interview that the WWW
was a passing fad and would never catch on in the United States!
It is important to understand four main points about the Internet:
it
it
it
it
was not designed to be secure
was not designed to have centralized management
is not operated by any one organization
was designed to be redundant
Before we continue our discussion of the Internet, we must briefly discuss its continuing evolution: Internet2.
Internet2 is a partnership of American universities, companies, and government laboratories working to develop
and promote the next generation of the Internet. Because of the advanced applications being developed within
Internet2, it requires high-speed telecommunication links. Internet2 currently operates at 10 gigabits per
second and supports transfer rates 100 to 1,000 times faster than typical broadband connections (Webopedia,
Module 1: The Internet
"Internet2"). A large portion of Internet2 is the result of a new Internet Protocol configuration, Internet Protocol
version 6 (IPv6). This will be explained further in the Internet Protocol section below.
Internet2 will also create new ways to use the Internet by using the Internet2 network infrastructure as a
conduit. Current Internet2 projects include telemedicine, digital libraries, and virtual laboratories (Webopedia,
"Internet2"). If you would like to learn more about Internet2, you can find links to additional information in our
Relevant URLs section.
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Internet Organizations
Although the Internet does not have a centralized management or operational structure, corporations and
governments do have a say about the how the Internet functions. The surprising thing, however, is the small
degree of control they have, mainly because so many corporations and governments are involved that none of
them individually has much power. In addition to corporations and governments, other Internet organizations
recommend and set standards for the Internet.
Corporations
Corporations exert influence on the Internet, and there are thousands of companies involved—however, no
single company dominates the Internet. In other words, although one company may dominate a particular
segment—such as browser market share, Internet access accounts, telecommunication links, or router
deployment—no company controls the Internet the way AT&T dominated the telephone industry years ago, the
way the U.S. Postal Service currently dominates the delivery of residential mail, or the way Microsoft dominates
the desktop operating system industry.
Governments
Some governments in the world rigidly control Internet access to limit the amount of information their citizens
can see. In contrast, until recently, the United States took a "hands-off" approach to Internet regulation. Yes,
laws were passed in the last few years, dealing mainly with pornography and, to a lesser extent, interstatecommerce taxation. However, either the U.S. Supreme Court struck down these laws or they had limited impact.
Nevertheless, because of world events and economic conditions, the United States and state governments are
exerting increasing levels of control over the Internet, especially in the areas of monitoring, security, and
interstate-commerce taxation.
Standards Setters
Standards-setting organizations provide for the ongoing viability of the Internet by developing, testing,
implementing, and publishing standards. Although there are many standards-setting bodies devoted to the
Internet, two groups have taken a major leadership role in this area:
the Internet Society (ISOC)
the World Wide Web Consortium (W3C)
The ISOC consists of individuals and organizations that actually created the Internet, as well as any
organization that wants to contribute to the maintenance of the Internet. The ISOC is also the organizational
home of the Internet Engineering Task Force (IETF), the Internet Architecture Board (IAB), the Internet
Engineering Steering Group (IESG), and the Internet Research Task Force (IRTF).
Here is how the process works:
The IETF develops the standards.
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The
The
The
The
IRTF conducts research, in conjunction with the IETF.
IESG considers the standards.
IAB handles an appeal if a standard is rejected by the IESG.
ISOC champions the standards as international standards.
The responsibility for developing WWW standards falls to the W3C, which develops standards for everything
from the HTTP protocol (in conjunction with the IETF) to Web-accessibility issues. For example, if your Web site
must comply with Section 508 of the Americans with Disabilities Act, you will find guidelines, checklists,
evaluations, and even training resources at the W3C Web site. The goal of the W3C, which was founded by Tim
Berners-Lee, is to develop open standards so that the Web evolves in a single direction rather than being
splintered among competing factions.
Other Internet standards-setting organizations include:
the
the
the
the
the
European Telecommunications Standards Institute (ETSI)
Internet Assigned Numbers Authority (IANA)
Internet Corporation for Assigned Names and Numbers (ICANN)
International Telecommunication Union (ITU)
Working Group on Internet Governance (WGIG)
You, as an individual, organization, or company, can join these organizations, although most require a
membership fee. We have provided individual hyperlinks in the above standards-setting organizations list so
that you can easily go to these organizations' Web sites. You will find these same links listed in our Relevant
URLs section.
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How the Internet Works
The Client/Server Model
The Internet operates on a principle called the client/server model. This model has three components:
the client
the network
the server
As an analogy, the Internet consists of train tracks (the network—connecting at many different intersections)
that carry and transfer data (the train cars) between the clients and the servers.
Below is an example of the client/server model in action:
Figure 1.1
The Client/Server Model
Module 1: The Internet
For example, if you go to a restaurant and order dinner from a waiter, he is acting in the capacity of a server. In
other words, he is giving or serving you something. You, meanwhile, are acting in the capacity of a client
because you are asking for or receiving a resource (dinner, in this case). In the client/server model, clients ask
servers for resources, such as files.
Because you are reading this module online, you are using a Web browser, which is an application on the client
computer. The software used to access network services is called client software. Examples include the e-mail
program, the browser, the chat program, and conference-meeting software. To view this page, your browser
contacted a Web server (WebTycho), and, using the Internet as the network to transfer the data, asked for a
resource (the page you are reading).
Server software is used to provide services to clients. When the network is large, a network may divide the
duties into separate servers, i.e., mail servers, print servers, Web servers, and so forth. To tell the Web server
which resources you want, you type in a Uniform Resource Locator (URL). The Web server then responds with
the page and you read it.
The key concept here is that the client is using a protocol, or set of rules, that the server understands. In this
case, it is the HyperText Transfer Protocol (HTTP). HTTP is the protocol that the client (browser) and server
(Web) understand. This concept applies to any type of service you are using on the Internet, such as
sending/receiving e-mail or transferring files.
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The Internet Infrastructure
The Internet works because most large telecommunication companies have their own dedicated backbones that
connect various localities. In each locality, the company has a point of presence (POP). Still, there is no single
entity controlling the overall network.
Instead, there are a few high-level networks connecting to each other through Network Access Points (NAPs).
On the Internet, the largest Internet Service Providers (ISPs) connect at NAPs at various points around the
world. At these points, the ISPs have to be able to handle trillions and trillions of bytes of data flowing through
each system.
The Internet depends on NAPs, backbones, and routers to talk to each other. Even with all of the traffic involved
and the different interconnection points, data sent out on the Internet by a user can travel around the world in
a second or less.
Module 1: The Internet
In reality, the Internet is a collection of large corporate networks that agree to communicate with each other at
the NAPs. This is how every computer on the Internet connects to every other computer on it.
Below is an illustration of the Internet infrastructure.
Figure 1.2
Internet Infrastructure
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Internet Protocols
Protocols are very specific rules for transferring information via the Internet. Protocols do the following:
provide methods for transferring messages
specify the format of messages
describe how to handle errors
As we mentioned earlier, to become part of the Internet, you must use TCP/IP-related protocols. Similarly, the
applications that you use to run different services on the Internet (such as Telnet, FTP, and e-mail) build their
own protocols based on TCP/IP.
TCP/IP
The most basic Internet protocol is Transmission Control Protocol/Internet Protocol (TCP/IP). TCP/IP (formally
called the TCP/IP protocol suite) actually consists of hundreds of protocols. TCP defines how Internet messages
are broken into packets for traveling over the Internet and then put back together once they arrive at their
destination. The main purpose of IP is to get the packet to its destination via the address part of each packet.
TCP is transparent while the IP is more visible because we can actually see the address we are using.
High-Level Protocols
Other protocols use TCP/IP to get application-specific data to the destination. We use these high-level or
application-level protocols for requesting software applications on remote computers to perform a specific
function for us.
Module 1: The Internet
Below are examples of these high-level protocols that we will discuss in this course:
Telnet
HyperText Transfer Protocol (HTTP)
File Transfer Protocol (FTP)
Simple Mail Transfer Protocol (SMTP)
Post Office Protocol (POP)
Network News Transfer Protocol (NNTP)
Figure 1.3
High-Level Protocols
It is important to note that if you use one of these high-level protocols, a server must exist somewhere on the
Internet and a client program must be present on the computer on which you are issuing the commands. For
example, if you want to download a file to your computer and you are using the FTP protocol, you must have an
address to the FTP server to retrieve the file and you will need an FTP client to talk to the FTP server to initiate
the request.
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Internet Addressing
Internet Protocol (IP) Addresses
Every computer on the Internet needs a unique number or address to identify it. The telephone network has the
same requirement. On the telephone network, this number is your telephone number. On the Internet, this
number is your IP address.
A typical international telephone number looks like this:
01-202-555-1212
A typical IP address looks like this:
Module 1: The Internet
131.171.11.23
The IP address above is the address for one of the United States–based WebTycho sites.
Both numbers (the telephone number and IP address) work in a similar fashion. In general, when reading the
numbers from left to right, we get closer to the actual telephone or computer. For example, the telephone
number is constructed as follows:
01
202
555
1212
=
=
=
=
North America
Washington, D.C.
a central office in the Washington, D.C., area
the actual number assigned to your telephone line,
which is connected to your telephone
An IP address consists of a 32-bit number that is actually written as four decimal numbers, with each number
separated by a period. This is known as the dotted decimal notation, and each piece of the address is called an
octet. Each number can be from 0 to 255.
An IP address has the following three parts:
the part that identifies its class
the part that identifies a particular network on the Internet
the part that identifies a particular device (host) within that network
The class of the address determines which part belongs to the network and which part belongs to the host.
There are three different classes or types of IP addresses that the average Internet user should be aware of:
class A, B, and C.
Below are three IP address examples, along with an interpretation of the addresses.
IP Address
Example
Class and Network
Designation
Host
Designation
Class A
95.158.200.120
95.
158.200.120
Class B
140.212.117.50
140.212.
117.50
Class C
210.167.210.220
210.167.210.
220
For example, the raw IP address in binary (shown below) translates to the dotted decimal Class B address of:
131.171.11.23.
10000011 10101011 00001011 00010111
131.171 = the class and network part of the address
11.23
= the actual computer or host within the network
When you receive an IP address, it is either a dynamic or static address. Normally, if you connect using one of
the major ISPs (such as Earthlink, MSN, or AOL) and use a dial-up connection, they have assigned you a
dynamic IP address. However, some ISPs (mainly cable companies and DSL ISPs) give you a static IP address.
Regardless, if you are using a Windows system, you can determine your IP address by typing the commands
"winipcfg" or "ipconfig" at the DOS command prompt when you log onto the Internet.
Module 1: The Internet
The current IP addressing system for the Internet is IPv4 (Internet Protocol version 4), but work is being done
on IPv6 (Internet Protocol version 6). Our current Internet Protocol (TCP/IP–IPv4) is now more than 20 years
old and is showing signs of its age. Most important, there is a growing shortage of IPv4 addresses needed by all
the new machines added to the Internet. IPv6 resolves this issue by lengthening IP addresses from 32 bits to
128 bits, allowing for considerable future growth of the Internet. For more information, see Understanding IPv6
by David Morton.
The Domain Name System (DNS)
IP addresses are hard for people to remember. To make it easier to remember the names of computers on the
Internet, the Domain Name System (DNS) was developed. For example, to access WebTycho, you only have to
remember tychousa.umuc.edu instead of 131.171.11.23.
When you use the Internet to send an e-mail message or to access WebTycho, you use a domain name to do so.
For example, "http://tychousa.umuc.edu" contains the domain name umuc.edu. However, the e-mail address
"smith@umuc.edu" also contains the domain name umuc.edu. Every time you use a domain name, you use the
Internet's DNS servers to translate the human-readable domain name into the computer-readable IP address.
Just like telephone numbers and IP addresses, domain names follow a hierarchy. However, the precedence is
reversed. There are top-level domains and subdomains. The top-level domain name has the highest precedence.
The most common top-level domain names include .com, .org, .net, .edu, and .gov. You may be surprised to
know that over 100 top-level domain names exist. You can see this list at the Internet Corporation for Assigned
Names' (ICANN's) list of top-level domains.
Within every top-level domain is a list of second-level domains. For example, in the .edu first-level domain
below, there are second-level domains.
University Name
Second-Level
Domain
University of Maryland University College
umuc.edu
University of North Carolina
unc.edu
Harvard University
harvard.edu
Howard University
howard.edu
Every name in the .edu top-level domain must be unique. The leftmost word, such as tychousa, is the host
name. It specifies the name of a specific computer, which has a specific IP address in a domain.
For example, the second-level domain "umuc.edu" could have subdomains such as www.us.umuc.edu,
ftp.us.umuc.edu, or xxx.us.umuc.edu, which are all valid domain names. In the domain www.us.umuc.edu, edu
is the top-level domain, umuc.edu is a second-level domain, us.umuc.edu is a third-level domain, and
www.us.umuc.edu is a fourth-level domain, which specifies the actual name of the computer (www.).
All of these names make IP addresses easier for us to remember, but a DNS server is necessary to process a
domain name request. DNS servers accept requests from programs and other name servers to convert domain
names into IP addresses. When a request comes in, the DNS server can do one of the following four things with
it:
If it knows the IP address, it will answer the request for the requested domain with an IP address.
It can contact another DNS server and try to find the IP address for the name requested.
It can respond to the request by saying, "I do not know the IP address for the domain you requested,
but here is the IP address for a DNS server that does know."
Module 1: The Internet
It can return an error message because the requested domain name does not exist or is invalid.
Figure 1.4
Domain Name Requests
If you should ever type a domain name into a client and nothing happens, or you receive an error message, try
using the IP address instead. The DNS could be down. For example, instead of typing http://www.umuc.edu,
type http://137.171.11.11.
By the way, if you know the domain name or host name, such as tychousa.umuc.edu, you can retrieve the IP
address by typing the command ping tychousa.umuc.edu at the DOS command prompt, if you are using
Windows.
One thing to remember is that although domain names are great for people, they are useless for computers.
That is why applications, like browsers, must find the IP addresses before they can get the resource you want.
To obtain a domain name for yourself or your business, you must register with a registrar. You can get a list of
registrars by going to the ICANN Web site. Once you are at the site, click on the Registrars Listing link to view a
list of certified registrars. In 2000, ICANN introduced seven new generic domain names: .aero (for the airtransport industry), .biz (for businesses), .coop (for cooperatives), .info (for all uses), .museum (for
museums), .name (for individuals), and .pro (for professions).
Uniform Resource Locator (URL)
Every resource on the Internet has a unique URL. The type of resource depends on the Internet application
protocol. For example, an HTML page (like the one you are reading) is an HTTP resource. The URL has four
parts:
the name of the protocol required to access the resource
a domain name that identifies a specific computer on the Internet
a port number, which is optional
the location of the file on the computer
Below is a representation of a URL:
Figure 1.5
The Uniform Resource Locator (URL)
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This tells your browser that you want to locate a Web page named schedule.htm, located in a folder named
/cmst385, on a computer named tychousa.umuc.edu.
Notice that this example does not include a port number. If you do not include a port number, the Web browser
will assume a default port number for the service you requested. For example, the default port number for Web
services (http://) is 80. If the Web server administrator changes the default port number on the Web server,
the URL must contain the port number. The following example uses a port number:
http://tychousa.umuc.edu:8080/cmst385/schedule.htm
Now, if you type in http://tychousa.umuc.edu/cmst385 instead (without specifying a file name), the Web server
will normally give you a file named index.htm or index.html, but it could be any name the system administrator
has specified. This is a default page. For example, if you access http://www.umuc.edu, you will notice that the
UMUC home page will display but there is no file name specified in the browser's command line at the top of the
screen. The default file for any specific folder is its index.html page. If a folder does not have an index.html file,
then depending on the UNIX settings/security settings, either you will see a list of files located within that folder
or you will get a message stating that you do not have permission to view the contents of the folder. We will
discuss these permission settings in module 5.
There are different types of URL protocols. A URL for a file that you want to fully download and save on your
computer requires that you specify the "ftp" protocol in the URL, for example:
ftp://tychousa.umuc.edu/cmst385/courses.doc.
If you are using the latest versions of most browsers, you need not include the protocol in a URL if you are
requesting a Web page. If you do not include the protocol, the Web browser assumes the http:// protocol. Note
that capitalization doesn't matter at this level either: http://www.umuc.edu/ and http://www.umuc.edu/ will
take you to the same place. However, when you are typing the specific file names (specifically on a UNIX
server) you must use appropriate capitalization. Typing www.umuc.edu/track1/Jones.html will take you to a
different location than www.umuc.edu/Track1/jones.html.
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Connecting to the Internet
Every computer that connects to the Internet is part of a network. For example:
You could be in a hotel lobby and connect to the Internet, via an ISP, using a wireless technology.
You could be at home and use your cable modem to connect to your ISP.
You could be at your office and connect to an ISP via a local area network.
From an Internet-user perspective, the most important component of the Internet connection process is
probably the Internet Service Provider (ISP). As a typical Internet user, however, you will use many different
components and services to access resources on the Internet. Below is an overview of the process.
Internet Connection Process
Module 1: The Internet
Internet
Components
Tasks
Resources
computer
(desktop, laptop,
PDA)
device you use to send
and receive multimedia
sound, video, camera, voice
recognition
communication
equipment
connects your computer
to the local loop
dial-up modem, regular telephone
line, DSL, cable modem, ISDN,
satellite, LANs, routers
local loop carrier
connects you to your ISP
communication lines, cable, satellite,
wireless
ISP POPs
logs you into your ISP
remote ports
Internet services
services you use to
access resources on the
Internet
DNS, e-mail, NNTP, Telnet, FTP, Web
ISP backbone
interconnects ISP POPs,
ISPs to other ISPs, and
ISPs to content
backbone providers, fiber optics lines,
NAPs
Online content
sites that contain the
resources you want
Web servers, portals, remote
computing, files
Origin of online
content
source of the content
legacy systems, scanned resources,
streaming audio and video,
telephony, phone, recordings, original
content
ISPs
Originally, people accessed the Internet by using a desktop computer, modem, and telephone line in their home.
Now, many people access the Internet through high-speed broadband connections and wireless remote
connections. According to a comScore news release, 36 percent of U.S. online users accessed the Web through
a high-speed connection in the fourth quarter of 2003 (March 2004). The Yankee Group estimates that U.S.
broadband home Internet use will grow to 66 percent by 2008. There are other access points as well, including
libraries, airports, televisions, handheld devices, cybercafés, and automobiles. In all of these scenarios, however,
you still need an ISP to get there.
When you connect to your ISP, you become part of their network. The ISP may then connect to a larger
network and, in turn, become part of its network. Again, the Internet is just a network of networks.
An ISP normally gives you three things to help you access the Internet: connection line (such as a telephone
line or cable), the software you need to connect, and technical support in case you have problems. In addition,
many ISPs provide Web site space and e-mail accounts.
There are also special types of ISPs, called online service providers, that provide additional services such as
special features, special content, and a home page that provides you links to many useful Internet sites.
Examples of ISPs that are also online service providers include EarthLink, AOL, AT&T, and MSN. During this
course, we will refer to any entity that provides Internet access as an ISP.
Module 1: The Internet
To identify ISPs in your area, you can use an online search engine or look in your telephone book under the
"Internet services and products" heading. Then call their customer service number and ask the representative
about the following factors:
Factors
ISP Considerations
Dial-in or remote
access
Does the ISP have a telephone number in your local area?
Does the ISP have a local or toll-free telephone number in the areas to
which you may travel?
Internet availability
How often will you get through when you actually try to access the
Internet? (You may conduct your own test by accessing your ISP at
different times.)
E-mail
Does the ISP offer e-mail accounts, and how many?
Can you access your account away from home by using the Web?
Performance
Is your e-mail delivered instantly or is it stored and delivered at specified
times?
How long does an average Web page take to download?
What is the uptime rate for the ISP?
Customer service and
technical support
Are technical support and customer service available online?
Is the telephone call toll-free?
What is the wait time once you make a call?
Are the support and service personnel courteous and knowledgeable?
Are the support and service personnel available when you need them?
Cost
Does the ISP offer different monthly subscriptions, such as a flat monthly
fee with unlimited access, or limited hours with additional hours for an
extra charge?
Does the ISP offer special features, content, or promotions?
Web site
Does the ISP give you space for a Web site?
How much space will you get and how much will it cost?
Is there a charge for traffic generated to and from your site?
Does your ISP support server-side technologies such as CGI, ASP, JSP, or
ColdFusion?
Upgrades
If using dial-up, can you upgrade to a faster service such as Digital
Subscriber Line (DSL)?
If using cable or DSL, how often is the connection software updated? Can
these updates be done remotely?
Many Internet sites compare ISP services. You can find links to these sites in our Relevant URLs section.
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Internet Connection Technologies
There are many ways to physically connect to the Internet. The physical connection between any two nodes can
be any type of electrical medium. The physical connection can be a telephone line, cable modem, Digital
Module 1: The Internet
Subscriber Line (DSL), satellite, an Integrated Services Digital Network (ISDN) line, a leased T-line, or wireless.
All that is necessary is that they use the common set of Internet-related protocols. Not all types of connections
are available in every geographic area, so your selection may be limited to what local providers offer. Following
is some information to help you make your choice.
Dial-Up Connection Using a Modem
Dial-up is the original way of connecting to the Internet. While online, however, the telephone is unavailable for
calls unless a line splitter is installed. Modems can be either external or internal. Your ISP will provide the
telephone number to use for your area, the settings you need, and the software on CD-ROM to install on your
computer.
The minimum standard for modem speed today is 56 kbps (56,000 bits per second), but you will never achieve
this upper limit on your home computer. First, there is a federal law that limits data transmission on the
telephone system to 53K. Second, you may have a "dirty" telephone line. To check this you can pick up your
telephone, press a key, and then listen to the background for pops, crackles, or even others' conversations. This
is "noise," which could affect your modem. These "noise" sources may be inside your home, outside, or both.
Some possible sources inside your home are:
telephone line placed too close to fluorescent lights or running motors
move the lines, if possible
dirty telephone wall sockets and jacks
clean the connecting pins on both until the original color appears
be sure to inspect all sockets that share the same telephone line, because a dirty socket in your
family room could affect your modem connection in your bedroom if they use the same line
try disconnecting extra devices on the line, such as extra telephones and fax machines, in other rooms
If you think the problem is outside your home, contact your telephone company and have someone there do a
check. However, the typical speed of a 56K modem will be from 42K to 50K.
U.S. Dial-Up Average Costs
Internet access
from free to $20 per month
modem
$25 to $80 (normally included with computer)
modem installation
$50 or self-installed
telephone cable
$10 or less
extra telephone line
$20 to $30 per month (optional)
DSL
DSL exists in different forms and they work at varying distances and speeds from the nearest telephone central
office. To get DSL, you must contact your local phone company or ISP and ask what is available for your
location. If you live outside a certain distance from the central office, you will be unable to get DSL. DSL can
significantly increase your connection speed versus a standard dial-up modem (384–1,000 kbps vs. 1.5–100
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mbps). Although it operates over normal telephone lines, you can use your telephone at the same time because
DSL uses a binary transfer of data. To gain the top range advertised by the DSL provider, you must live within a
three-mile radius of the company providing access. DSL is also an "always-on" connection; you will need a
firewall.
U.S. DSL Average Costs
Internet access
$40 to $50 per month
modem and cable
$80 to $260 (sometimes free with promotion)
installation
$40 to $60 (sometimes free with promotion)
Cable Modems
Cable modems connect to the Internet through a cable TV line at a far greater speed than dial-up. This medium
has a faster transfer rate (around 512 kbps) and is not affected by outside weather patterns. The connection is
"always-on" (unless you turn off your computer) and it does not tie up the phone line. Multiple computers can
be networked through a router, allowing everyone on each household computer to be online at the same time.
If you subscribe to cable TV and cable Internet, you can even watch TV and access the Internet at the same
time. You will need an Ethernet card, which comes standard on most computers.
If you have an "always-on" connection, you will need a firewall to protect the data on your computer. We will
talk about this topic more in module 6. In addition, if you are the first in your neighborhood or apartment
building to get cable modem, you will have a very fast connection because no one else is sharing your
bandwidth. However, because cable connections use an Ethernet technology, the more people that connect to
your cable modem segment, the less bandwidth is available for you.
U.S. Cable Modem Average Costs
Internet access
$35 to $55 per month
modem and cable
$80 to $260 (sometimes free with promotion)
installation
$40 to $60 (self-installation kits available)
additional computer connection
$5 to $15 (if offered)
extra telephone line
$20 to $30 per month (optional)
Satellite
With one-way satellite, you need a conventional modem and a telephone link to an ISP for uploads, and a
satellite dish for downloads. Satellite data transfer speeds range around 400 kbps. Two-way satellite systems
allow you to both upload and download through your satellite dish. Compared to other services, a satellite
connection is quite expensive. However, if you do not have cable or do not live within the required distance for
DSL, this may be your only high-speed option. To aim the satellite dish, satellite requires a clear line of sight to
the south (or to the north, if you are located south of the equator).
U.S. Satellite Average Costs
Internet access
$50 or more per month (depending on the number of hours)
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two-way system
$250 to $575
installation
$175 to $250 (sometimes free with promotion)
ISDN
A single ISDN line can handle up to eight devices, including a computer, telephone, fax, and video, and you can
operate any two devices at the same time. ISDN operates over standard telephone and fiber-optic lines. Costs
vary, depending on a particular country's infrastructure. ISDN is not readily available in the United States, so
the cost can be quite high; however, ISDN is available just about everywhere in Japan, so the cost is
comparatively low. ISDN is slower than cable, running at about 128 kbps.
U.S. ISDN Average Costs
Internet access
$30 to $35 per month
equipment
$125 to $350
installation
$45 to $110
router
$250
T-Lines
Businesses are the primary users of T-lines; however, some apartments, condominiums, and college
dormitories offer these connections as a service for their residents. T-lines are direct, dedicated links to the
Internet. They are very expensive and are usually used by ISPs to provide high-volume customers with Internet
access or by businesses that want to set up private networks. T1 links provide 1.5 mbps connections and T3
lines provide 44 mbps connections.
Wireless Technologies
Wi-Fi (wireless fidelity) is a wireless local area network technology. It works by adding short-range radios to
stationary computers, laptops, and handheld personal digital assistants (PDAs). In addition to homes and offices,
you can find Wi-Fi connection points in airports, cafés, and hotels, which means that you can access the
Internet from almost anywhere. If you use this technology, make sure you follow proper security precautions to
prevent someone from tapping into your signal.
Bluetooth is a specification that describes how PDAs, mobile phones, and computers can connect with each
other and with home and business phones and computers, using a short-range wireless connection. Bluetooth
requires that a low-cost transceiver chip be included in each device. As with Wi-Fi, you should follow proper
security precautions.
Wireless Access Protocol (WAP) is actually a set of protocols that standardize how wireless devices, mainly
mobile phones, access the Internet. WAP allows the user to access such things as Web pages, e-mail, and chat.
WAP follows the Internet's client/server approach and pushes much of the processing to the server, allowing the
wireless device to have a small footprint. WAP's main selling point is its ability to allow interoperability among
different devices and services.
U.S. Wireless Average Costs
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Internet access
$30 to $40 per month
base station (for home computer)
$125 to $650
access device (for each unit such as PDA, cell phone)
$70 to $95
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These are the popups for this section, in order of their appearance.
Popup 1:
Computer—By definition, a computer is a microprocessor. What you use at home or work is actually a computer
system. However, for the sake of simplicity, we will use the term computer throughout this course.
Popup 2:
Protocol—The methods or rules by which two computers agree to communicate.
Popup 3:
/CMST385/0602/Modules/M1-Module_1/../G1-Glossary.html#TCP/IP
Popup 4:
Intranet—A private network in an organization or enterprise that uses TCP/IP, HTTP, and other Internet
protocols.
Popup 5:
Extranet—An intranet that can be securely accessed by an organization's customers, partners, suppliers, and
vendors.
Popup 6:
Topology—The shape of a local-area network (LAN) or other communications system. Topologies are either
physical or logical. Types of topologies include bus, ring, star, and tree formations.
Module 1: The Internet
Popup 7:
LAN—A computer network that spans a relatively small area. Most LANs are confined to a single building or
group of buildings.
Popup 8:
MAN—Metropolitan Area Network, a data network designed for a town or city. In terms of geographic breadth,
MANs are larger than local-area networks (LANs), but smaller than wide-area networks (WANs).
Popup 9:
WAN—A wide-area network (computer network) that spans a relatively large geographical area. Typically, a
WAN consists of two or more local-area networks (LANs).
Popup 10:
Host—Also called a server, a host is a computer connected to other computers for the purposes of sharing its
resources. Resources include applications, files, peripherals, databases, and Internet connectivity. Computers
connected to the host are known as workstations.
Popup 11:
Protocol—The methods or rules by which two computers agree to communicate.
Popup 12:
Address space—The set of names that can be referenced on the network is called an address space. The
common address space is similar to your telephone number in that each address must be unique.
Popup 13:
http://www.zakon.org/robert/internet/timeline/
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Browser—A program that allows you to view Web pages.
Popup 15:
http://www.internet2.edu/
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http://www.ietf.org/
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http://www.irtf.org/
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http://www.ietf.org/iesg.html
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http://www.iab.org/
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http://www.isoc.org/
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http://www.etsi.org/
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http://www.iana.org/
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http://www.icann.org/
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http://www.itu.int/home/
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http://www.wgig.org/
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Clients—Computers on which you run applications, such as word processors, spreadsheets, Web browsers, and
e-mail programs.
Popup 27:
Servers—On the Internet, servers are very fast computers dedicated to managing files, printers, or network
traffic, such as Web or e-mail servers.
Popup 28:
Protocol—The methods or rules by which two computers agree to communicate.
Popup 29:
Backbone—A very high-capacity transmission line or pathway that carries data gathered from local and regional
networks.
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Point of presence (POP)—A place for you to access a company's network, usually without having to pay for the
connection.
Popup 31:
Network Access Points (NAPs)—In the United States, a NAP is one of six major Internet interconnection points
that serve to move all Internet traffic.
Popup 32:
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Internet service providers (ISPs)—Companies that provide other companies and individuals access to the
Internet. An ISP has the telecommunication lines and equipment to have a point of presence on the Internet for
the geographic area served.
Popup 33:
Packets—When you send or receive any type of message on the Internet, that message is broken into packets.
A packet is the unit of data sent or routed between an origin (you) and a destination (such as an e-mail server).
Along with the data, the packet contains the originating IP address and the destination IP address.
Popup 34:
Transparent—If a connection or process is transparent, it works in the background; the user does not need to
do anything to have the operation performed.
Popup 35:
Telnet—A program that allows you to remotely log into other computers on the Internet and is part of the
TCP/IP protocol suite. You can manage files, use resources, and execute programs.
Popup 36:
HyperText Transfer Protocol (HTTP)—The set of rules for exchanging text, graphic images, sound, video, and
other multimedia files between a Web browser and Web server. The main purpose of HTTP is to transfer
displayable Web pages and related files to your Web browser and other devices. A key concept of HTTP is that a
file can contain references (or links) to other files. When you click on the links, the file referenced is sent to
your browser.
Popup 37:
File Transfer Protocol (FTP)—The simplest, but not the only way to exchange files between computers on the
Internet. Its main purpose is to upload and download programs and other files from and to your computer to
and from other computers.
Popup 38:
SMTP—Simple Mail Transfer Protocol, a protocol for sending e-mail messages between servers. Most e-mail
systems that send mail over the Internet use SMTP to send messages from one server to another; the
messages can then be retrieved with an e-mail client using either POP or IMAP.
Popup 39:
Post Office Protocol (POP)—POP3 is the most recent version of a standard protocol for receiving e-mail. When
someone sends you Internet e-mail, it is stored in your mailbox at a POP server and is held there for you until
you request that it be downloaded to your computer via an e-mail client.
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Popup 40:
Network News Transfer Protocol (NNTP)—An Internet protocol used to post and retrieve messages on
newsgroups. NNTP servers manage the worldwide network of newsgroups and include the server at your ISP.
An NNTP client is included as part of your browser or e-mail client. You can also use a separate program called a
newsreader. Newsgroups allow you to find the answer to virtually any question you may have. NNTP is the main
protocol used by computers for managing the notes posted on newsgroups
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IP address—A number that identifies each sender or receiver of data that is sent in packets across the Internet.
Although the latest version of the IP is version 6, we will illustrate version 4 in this course because it is the most
widely used.
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Central office—A central office (CO) is an office or a building in a locality that your home or business telephone
line is connected to and has switching equipment that can switch calls locally or to long-distance carrier phone
offices.
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Bit—Bit is short for binary digit and is the smallest unit of data a computer can understand. A bit can be either a
0 or a 1.
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Dynamic—To save money, most corporate networks and ISPs make their users share a pool of IP addresses.
These IP addresses are called dynamic because each time you log into your network or ISP, you get a new one.
Popup 45:
Static—A static IP address is permanently assigned to you.
Popup 46:
http://www.pcsupportadvisor.com/nasample/c0655.pdf
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DNS—Domain Name System (DNS) serves maps (or equates) text names to IP addresses automatically.
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Top-Level Domain—In the Domain Name System (DNS) naming of computers, there is a hierarchy of names.
The root of the system is unnamed. There is a set of what are called top-level domain names (TLDs). There is a
small set of generic top-level domain names: com for commercial endeavors, org for nonprofit organizations,
net for network providers, mil for military organizations, gov for government organizations, and edu for
educational organizations. There are also a number of top-level domain names for individual countries, including
Canada (ca), Australia (au), and the United Kingdom (uk).
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http://data.iana.org/TLD/tlds-alpha-by-domain.txt
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Second-Level Domain—The portion of a Uniform Resource Locator (URL) that identifies the specific and unique
administrative owner associated with an Internet Protocol (IP) address. The second-level domain name includes
the top-level domain name. For example, in: www.whatis.com, "whatis" is the second-level domain and ".com"
is the top-level domain.
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http://www.icann.org/registrars/accredited-list.html
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URL—The address of a file or resource available on the Internet.
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http://www.umuc.edu/
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Local loop—The connection from a telephone company's central office to your telephone. This connection is
usually a pair of copper wires called a twisted pair.
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Local loop carrier—A local carrier that rents or sells telecommunication transport.
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Modem—Modem stands for modulate/demodulate. It converts a digital signal originating from your computer to
an analog signal so the signal can be transmitted over your telephone line to your central office. It also takes an
incoming analog signal coming from your central office and converts it to a digital signal that your computer can
understand.
Popup 57:
Broadband—Data transmission in which a single medium (wire) can carry several channels at once. Cable TV,
for example, uses broadband transmission. In contrast, baseband transmission allows only one signal at a time.
Cable and DSL computer networks use broadband transmission.
Popup 58:
http://www.internetworldstats.com/articles/art047.htm
Popup 59:
http://www.internetworldstats.com/am/us.htm
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Nodes—Computing devices that are members of the Internet.
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Line splitter—A line splitter divides a telephone signal into two or more signals.
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Ethernet—A networking technology that allows your computer to connect to a network.
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Module 1: The Internet
Firewall—Allows you to restrict access to and from your computer.
Popup 64:
/CMST385/0602/Modules/M1-Module_1/../G1-Glossary.html#footprint
Module 1: The Internet
Self-Assessment
Directions: Test yourself on how well you know the material. You will get the correct answers when you click
the Submit button at the bottom. There are no grade points for this online review.
Multiple choice: Select the best answer for each of the following:
1. A computer that is able to function on a network is a:
A. protocol
B. host
C. parcel
D. helper
2. The method or rules by which two computers agree to communicate is the:
A. communication link
B. protocol
C. sign
D. commentary
3. The organization that develops WWW standards for the Internet is the:
A. W3C
B. ISOC
C. REP
D. ESOC
4. In reference to the Internet, the three components of the client/server model are the client, the
server, and the:
A. port
B. host
Module 1: The Internet
C. protocol
D. network
5. The six major Internet connection points that serve to move all Internet traffic in the United
States are called:
A. NAPs
B. CAPs
C. HAPs
D. PAPs
6. Which of the following is not considered a high-level protocol?
A. POP
B. NNTP
C. TCP
D. HTTP
7. The protocol used for exchanging text, graphic images, sound, video, and other multimedia files
between a Web browser and Web server is:
A. Telnet
B. HTTP
C. FTP
D. SMTP
8. A number that identifies each sender or receiver of data that is sent in packets across the
Internet is called a(an):
A. communication address
B. IP address
C. TCP address
D. routing address
9. What system was developed to make it easier for people to remember the names of computers on
the Internet?
A. DNS
B. SMS
C. MSN
D. POP
Module 1: The Internet
10. The unique address of a file or resource on the Internet is called a:
A. PPP
B. UPP
C. URL
D. PRL
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Exercises
Due dates for the following assignments and directions for submitting assignments are listed in the Course
Schedule section of your syllabus.
Task
1. Research the availability and cost of DSL and cable modems in your area. Contact your local telephone
and cable companies and find out whether these services are available in your area and what they cost.
Review Questions
1. What is an internet? Identify the similarities and differences between an internet and the Internet.
2. Describe the HTTP protocol and explain why it is important to the Web.
3. What is ARPANET and what is its relationship to the Internet?
4. What is the World Wide Web Consortium and why is it important to the Internet?
5. Describe HTML and explain why it is important to the Web.
6. Describe the difference between a LAN and a WAN.
7. Briefly explain the client/server concept as it relates to the Internet.
8. What is an advantage of using cable modems?
9. How is ADSL different from ISDN?
10. Identify and explain the three basic sections of a URL.
11. If you are using a 56K modem, how long would it take to load a graphic that has 150,000 bytes?
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