Exploring the Digital Domain: An Introduction to Computers and Information Fluency, Second Edition
Chapter 18
The Internet
Questions for Review and Answers
1. Give a brief overview of the history of the Internet.
In the late 1960s, the U.S. Department of Defense created a network of computers
that could communicate with each other over long distances. This network came
to be known as ARPANET. Experiments continued, and the network grew during
the 1970s. In 1978 the TCP/IP protocol was established. Then in the early 1980s,
the University of California at Berkeley developed a flavor of UNIX that
incorporated TCP/IP. Also in the 1980s, ARPANET was expanded. When the
Department of Defense decommissioned ARPANET in 1990 more commercial
firms joined the network and the Internet was born.
2. The Internet has been described as a packet switching, loosely coupled,
distributed network of networks. Explain what this means.
The Internet is a confederation of many separately owned and operated networks.
There is a dedicated infrastructure that links these networks and ensures global
connectivity.
3. What does TCP/IP stand for? What role does the TCP/IP protocol suite play in the
functioning of the Internet?
TCP/IP stands for Transfer Control Protocol/Internet Protocol. TCP/IP is the
common protocol used for data transmissions between systems over the Internet.
4. What is a datagram? How does IP handle datagrams?
A datagram is a sequence of packets that contains the information that is
transmitted over the Internet. IP is responsible for routing the datagrams.
5. What is an IP address? What structure do these addresses have?
Each computer system that is officially part of the Internet has an IP address.
These addresses consist of four numbers-each of which is less than 256.
6. How are domain names related to IP addresses?
Domain names must be converted to IP addresses for deliver.
7. What is DNS? How is it used?
Exploring the Digital Domain: An Introduction to Computers and Information Fluency, Second Edition
DNS stands for Domain Name System, which is a method used for addressing
that is more convenient than IP addresses.
8. How are DNS servers organized to resolve domain names?
DNS servers are distributed at different levels throughout the network. The
system is organized like an IT-version of connecting to Kevin Bacon (as in “six
degrees of separation”).
9. Compare and contrast TCP with UDP as transport or messaging services.
TCP creates a connection-based, or guaranteed, messaging service. TCP is a more
sophisticated form of transport than UDP, which provides simple connectionless
packet transport and does not guarantee delivery.
10. What does it mean when we say that TCP/IP is an open system? Why is this an
advantage for its use with the Internet?
There is neither centralized control nor a favored hardware platform with TCP/IP.
This is an advantage for its use with the Internet because it means that everyone
has potentially equal access to the Internet.
11. What are the chief advantages of the layered architecture for Internet software and
services?
Layered architecture provides greater flexibility. Applications can pick and
choose from different types of messaging services. This division of labor makes
things simpler, too.
12. What are asynchronous transactions? What are its advantages as a form of
communication?
Asynchronous transactions are point-to-point transactions. The advantage of them
is they acknowledge delivery to the sender.
13. Explain how the client/server communication process is organized. What are the
advantages of this approach?
Client programs and server programs interact with one another. Usually, the
server program runs continuously on a given computer system. When the user
requests that a file be transferred to his or her computer, the client program that
manages file transfers on the user’s system issues a request to the remote
computer’s server program. The details of the exchange are handled between
these two processes.
Exploring the Digital Domain: An Introduction to Computers and Information Fluency, Second Edition
The advantages of this approach are that distributing the work frees the client
from hardware/software demands that might be needed only sporadically.
Secondly, computers acting as servers are able to respond to a number of user
requests, even computing ones. Third, the client/server model can link together
systems that are based on different hardware platforms.
14. How does electronic mail compare with other forms of communication like postal
mail and telephone service?
E-mail messages are posted to individuals at specific addresses much like
conventional mail. Also, like regular mail, e-mail communication is an example
of an asynchronous transaction. The sender’s system and receiver’s system do
not have to be connected when the sender sends the message. For many, this is far
superior to telephone communications that necessitate both individuals being
available simultaneously. Unlike conventional mail, e-mail is much faster.
15. What is telnet? What is it used for?
Telnet is a remote login program that automatically resolves translation problems
between different systems.
16. What is FTP? What is it used for?
FTP, or file transfer protocol, is a protocol that is used for transporting and
translating documents and data from one platform to another over networks.
17. What is anonymous FTP?
Anonymous FTP allows you to temporarily connect to a designated FTP host and
copy files to your own machine from a server with open file access.
18. Explain how telnet and FTP can be used in installing and maintaining your own
Web site on a remote host.
Using telnet and FTP together, you can move files from your disk to the Web
site’s remote host’s disk, which is not possible when using Web services alone.
19. What is a cookie? How is it used in Web transactions?
A cookie is a special number that identifies a user and his or her transactions with
a server. When a user revisits a Web server, the browser sends the cookie to the
server. In this way, the server knows that this is the same user identified
previously.
20. What is a Web cache? How does a Web client cache work?
Exploring the Digital Domain: An Introduction to Computers and Information Fluency, Second Edition
Web caching is the storing of Web objects for possible reuse. Web caches are
typically built into the Web client. Your browser retains some of the pages that
you have visited earlier. When you ask to visit a site that you have surfed
previously, the browser will ask the Web server if the page or object is newer than
the copy it has currently stored. If the object is unchanged, then the time spent
downloading a new copy will be saved.
21. What is a proxy server? What are the advantages and disadvantages of proxies?
A proxy server is a Web server that acts as a go-between by caching Web objects
for delivery to Web clients. One advantage of proxy servers is that they provide
the possibility of faster response time for clients. Inside an intranet, this can
reduce the demand for external traffic, which can also support security measures.
Outside and intranet, it may help reduce the already congested Web traffic.
22. Give a brief overview of the Internet2 project. What advantages or opportunities
does it offer over the current Internet?
The Internet2 Project was established to meet the demands for the future of global
networking. Internet2 is a consortium of government, industry, and education that
are partnering to foster research and development in the next generation Internet
and Internet applications. The Internet2 Project has pioneered research and
development in new networking capabilities such as multicasting and the next
generation of IP addressing. They have also established high-performance
networks linking the campuses and labs of its members. Internet2 has also led the
way in the development of innovative applications for tele-immersion for remote
instrumentation and virtual laboratories, digital libraries, and distance learning.