The Internet is a network of networks that links computers called
servers that contain Web pages and computers called clients that request to see
Web pages. The entrance point to the Internet is typically through an Internet
Service Provider (ISP), which is an organization that sells access to the
Internet for a small monthly charge.
INTRANETS AND EXTRANETS
Intranet
An internal corporate network built using
Internet and World Wide Web standards and products that allow employees of an
organization to gain access to corporate information. Extranet A network based
on Web technologies that links selected resources of the intranet of a company
with its customers, suppliers, or other business partners (e.g. Schwab).Businesses are finding other uses for Internet technology
besides communicating with anyone in the world. Two of those new uses are to
use this technology to communicate within an organization and among business
partners.
The term Intranet is used to describe Internet technology
used on a local area network to provide e-mail, Web pages, and other
communication methods to employees. Employees use the same browser used to
access the Internet to access the company’s Intranet. However, anyone who is
not connected to the organization’s local area network is unable to access the
Intranet.
Web site owners may not have all the relative information they
think they have about visitors to their Web site. Clever Web surfers create
virtual identities that conceal their true identity. For example, they create a
ficticious name, then open a free e-mail account using that name. Instead of providing
a Web site with their personal information, they provide a fake profile.
This enables the surfer to join free Web sites and participate in
discussions without fearing that the site owner will learn any real information
about them. This sounds dubious, but so are Web site owners who collect
information about you and sell it to advertisers without your permission.
There’s nothing illegal about creating a virtual identity as long
as you don’t attempt to defraud the Web site owner. For example, you must give legitimate
information when making a purchase, but by then you should be comfortable
dealing with that Web site.
Intranets are used to distribute employee information, provide Web
page-based forms that are completed online, and give authorized employees
access to data stored in the organization’s databases.
An Extranet is frequently
used to link business partners, such as suppliers, vendors, and trading
partners, who conduct frequent business transactions with an organization.
Let’s say you provide office supplies to 100 businesses. Instead of the office
staff quoting prices, checking availability, and tracking orders, every
customer can do this by logging on your Extranet.
An Extranet connects business partners. (Redrawn with permission
from Prentice Hall. Dodd, Annabel Z. The Essential Guide to Telecommunications.
Upper Saddle River, NJ: Prentice Hall, 2000, p. 306.) ch06.fm Page 216 Tuesday,
August 15, 2000 11:23 AM
Typically, a customer uses the Internet address to visit your
site, then uses an ID and a password to gain access to the Extranet Web pages.
From that point, it is as if the customer is viewing a normal Web page. An
Extranet automates many of the normal business transactions that require human
interaction but can easily be automated. Many inquiries require a sales
assistant to look up the information in the company’s computer system.
The Extranet gives customers controlled access to that computer
system. Security is a critical concern to owners of Extranets since the owner
is relying on the skills of the IS department to write a program that addresses
all the facets dealing with a customer. The owner does not want incorrect
information to be sent to the customer, nor does the owner want to frustrate
the customer before he or she is able to talk to a person.
Extranets satisfy security concerns by using encryption,
authorization, and integrity checks. Encryption mixes up data so it isn’t
easily read, as discussed previously in this chapter. Authorization requires
the customer to use a unique ID and password to access the Extranet. Integrity
checks consist of logic written into a program to ensure that the interaction with
the customer makes sense. For example, a small business that buys 10 reams of
paper every month is unlikely to order 100 reams one month, so the Extranet ordering
program would flag the order and bring it to the sales rep’s attention.
The Internet is a network of networks that links computers called
servers that contain Web pages and computers called clients that request to see
Web pages. The entrance point to the Internet is typically through an Internet
Service Provider (ISP), which is an organization that sells access to the
Internet for a small monthly charge.
An ISP leases one or more T carrier-lines from the telephone
company, which enables the ISP to transmit and receive information on the
Internet. Depending on the type of T carrier-line, the ISP will have a minimum
of 24 communications channels over which data can be communicated 24 hours, 7
days a week. Every telephone company has its own telecommunication network that
links ISPs and organizations that directly link their servers to the Internet
without going through an ISP. Telephone companies exchange Internet data at
regional centers called peering centers. There are four public peering centers
and many private peering centers
operated by telecommunications carriers. Every device on the
Internet has a unique Internet address, which is a set of numbers. An Internet
address, also known as an IP address, is often identified by a Web site name
that is associated with the IP address, such as www.keogh.org.
You and I can visit a Web site by dialing our ISP, then using
software called a browser to request and display Web pages. After entering the
Web site name, the browser sends the request to the ISP, which searches the
Internet telephone book to locate the IP address associated with the Web site
name. Once the IP address is found, the ISP contacts the Web site and requests
a page. The first page that is requested is the site’s home page, unless your
request specifies another page. The Web page is sent to your ISP from the Web
site and is passed to your computer, where the browser reads and displays the
page.A Web page is written using HTML or an enhanced version of that language called
XML. Programmers who build the Web page insert HTML and XML tags into the page
that tell the browser how to display the page.
In addition to tags that specify the text format, there are tags
that tell the browser what graphics to display and how to link to other Web
pages. These tags are called hyperlinks. A hyperlink is typically highlighted
text or a graphic that, when clicked on, tells the browser to request either
another block of text on that Web page or to display another Web page.
Information travels over the Internet in small electronic
envelopes called datagrams. The TCP/IP protocol suite controls datagram traffic
on the Internet. The Internet Protocol (IP) describes how datagrams are
constructed and transmitted. The Transmission Control Protocol (TCP) is used to
manage the transmission. TCP, for example, requires a timer to be activated
when a datagram is transmitted. If an acknowledgement has not been received
when time has expired, then the datagram is resent because TCP assumes the
first one was lost or discarded during transmission.
The Internet groups the different ways to transfer information
over the Internet into Internet services. Four popular services are Telnet,
e-mail, FTP, and HTTP (World Wide Web). The Telnet service enables a person to
directly interact with a remote computer. The e-mail service enables people
linked to the Internet to exchange electronic mail. The FTP service is used to
copy files to and from a remote computer.
HTTP is the service used to exchange Web pages. Security and
privacy concerns are a serious threat to the viability of the Internet as a
tool for electronic commerce. Cyber crooks can use a variety of methods to gain
access to a server or prevent legitimate visitors from accessing a server.
Organizations whose servers are connected to the Internet use various
techniques to thwart such attacks by password-protecting sites and using
firewalls and proxy servers.
Anyone who visits a Web site must be on alert that the owner of
the site might be creating a visitor’s profile, which identifies you and your
interests, and might sell your profile to a third party. Internet technology is
also used within an organization and its business partners by creating an
Intranet and Extranet.
An Intranet is an organization’s private Internet that enables employees to
share information and access corporate data. An Extranet is also a private
Internet, but it is used to link business partners, such as key vendors, and to
track orders, sales, and other information typically exchanged by business partners. By Kimena Nuhu.
