Business Data Communications and Networking, 12th Edition solutions manual and test bank
Jerry FitzGerald, Alan Dennis Alexandra Durcikova
August 2014, ©2014
View Previous Edition of This Title
Over the past few years, many fundamental changes have occurred in data, communication, and networking that will shape the future for decades to come. Updated with the latest advances in the field, Jerry FitzGerald, Alan Dennis and Alexandra Durcikova's 12th Edition of Business Data Communications and Networking continues to provide the fundamental concepts and cutting-edge coverage of applications that students need to succeed in this dynamic field. Authors FitzGerald, Dennis and Durcikova have developed a foundation and balanced presentation from which new technologies and applications can be easily understood, evaluated, and compared.
Chapter 1 Introduction to Data Communications
1.1 Introduction
1.2 Data Communications Networks
1.3 Network Models
1.4 Network Standards
1.5 Future Trends
1.6 Implications for Management
Chapter 2 Application Layer
2.1 Introduction
2.2 Application Architectures
2.3 World Wide Web
2.4 Electronic Mail
2.5 Other applications
2.6 Implications for Management
Chapter 3 Physical Layer
3.1 Introduction
3.2 Circuits
3.3 Communication Media
3.4 Digital Transmission of Digital Data
3.5 Analog Transmission of Digital
3.6 Digital Transmission of Analog Data
3.7 Implications for Management
Chapter 4 Data Link Layer
4.1 Introduction
4.2 Media Access Control
4.3 Error Control
4.4 Data Link Protocols
4.5 Transmission Efficiency
4.6 Implications for Management
Chapter 5 Network and Transport Layers
5.1 Introduction
5.2 Transport and Network Layer Protocols
5.3 Transport Layer Functions
5.4 Addressing
5.5 Routing
5.6 TCP/IP Example
5.7 Implications for Management
Chapter 6 Network Design
6.1 Introduction
6.2 Needs Analysis
6.3 Technology Design
6.4 Cost Assessment
6.5 Implications for Management
Chapter 7 Wired and Wireless Local Area Networks
7.1 Introduction
7.2 LAN Components
7.3 Wired Ethernet
7.4 Wireless Ethernet
7.5 The Best Practice LAN Design
7.6 Improving LAN Performance
7.7 Implications for Management
Chapter 8 Backbone Networks
8.1 Introduction
8.2 Switched Backbone
8.3 Routed Backbones
8.4 Virtual LANs
8.5 The Best Practice Backbone Design
8.6 Improving Backbone Performance
8.7 Implications for Management
Chapter 9 Wide Area Networks
9.1 Introduction
9.2 Dedicated-Circuit Networks
9.3 Packet-Switched Networks
9.4 Virtual Private Networks
9.5 The Best Practice WAN Design
9.6 Improving WAN Performance
9.7 Implications for Management
Chapter 10 The Internet
10.1 Introduction
10.2 How the Internet Works
10.3 Internet Access Technologies
10.4 The Future of the Internet
10.5 Implications for Management
Chapter 11 Network Security
11.1 Introduction
11.2 Risk Assessment
11.3 Ensuring Business Continuity
11.4 Intrusion Prevention
11.5 Best Practice Recommendations
11.6 Implications for Management
Chapter 12 Network Management
12.1 Introduction
12.2 Designing for Network Performance
12.3 Configuration Management
12.4 Performance and Fault Management
12.5 End User Support
12.6 Cost Management
12.7 Implications for Management
Chapter 2
Application Layer
Chapter Summary
The Application Layer (also called layer 5) is the software that enables the user to perform useful work. The software at the application layer is the reason for having the network because it is this software that provides the business value. This chapter examines the five fundamental types of application architectures used at the application layer (host-based, client-based, client-server, cloud-based, peer to peer). It then looks at the Internet and the primary software application packages it enables: the Web, email, Telnet, and instant messaging.
Learning Objectives
After reading this chapter, students should be able to:
· understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures
· understand how the Web works
· understand how email works
· be aware of how Telnet and instant messaging works
Key Terms
application architecture
application logic
client-based architecture
client-server architecture
cloud computing
cluster
data access logic
data storage
desktop videoconferencing
distributed computing
model
dumb terminal
green computing
H.320
H.323
host-based architecture
HTTP request
HTTP response
Hypertext Markup Language (HTML)
Hypertext Transfer Protocol (HTTP)
instant messaging (IM)
Internet
Internet Message Access Protocol (IMAP)
mail transfer agent
mail user agent
mainframe
middleware
MPEG-2
Multipurpose Internet Mail Extension (MIME)
network computer
n-tier architecture
peer-to-peer architecture
personal computer
Post Office Protocol (POP)
presentation logic
protocol
request body
request header
request line
response body
response header
response status
scalability
server virtualization
Simple Mail Transfer Protocol (SMTP)
SMTP header
SMTP body
Telnet
terminal
thick client
thin client
three-tier architecture
transaction terminal
two-tier architecture
uniform resource locator (URL)
videoconferencing
virtual server
World Wide Web
Web browser
Webcasting
Web server
Chapter Outline
1. INTRODUCTION
2. APPLICATION ARCHITECTURES
a. Host-Based Architectures
b. Client-Based Architectures
c. Client-Server Architectures
d. Cloud Computing Architectures
e. Peer-to-Peer Architectures
f. Choosing Architectures
3. WORLD WIDE WEB
a. How the Web Works
b. Inside an HTTP Request
c. Inside an HTTP Response
4. ELECTRONIC MAIL
a. How E-Mail Works
b. Inside an SMTP Packet
c. Attachments in Multipurpose Internet Mail Extension
5. OTHER APPLICATIONS
a. Telnet
b. Instant Messaging
c. Videoconferencing
6. IMPLICATIONS FOR MANAGEMENT
SUMMARY
Answers to Textbook Exercises
1. What are the different types of application architectures?
Host-based (all processing done on host system and all data on host with terminals providing access), client-based (with processing done on client and all data stored on server), and client-server (balanced processing; usually host provides data access and storage while the client provides application and presentation logic).
2. Describe the four basic functions of an application software package.
Data storage, data access logic, application logic, and presentation logic.
3. What are the advantages and disadvantages of host-based networks versus client-server networks?
| Host-based | Client-server | |
| Advantages | Centralized security Integrated architecture from single vendor Simpler, centralized installation | Balanced processing demands Lower cost; inexpensive infrastructure Can use software and hardware from different vendors Scalability |
| Disadvantages | Having all processing on host may lead to overload Cost of software and upgrades; expensive infrastructure Terminal totally dependent on server | Problems with using software and/or hardware from different vendors More complex installation or updating (although automated installation software helps greatly in this area). |
4. What is middleware and what does it do?
Middleware manages client-server message transfer and shields application software from impacts of hardware changes. Middleware provides standard communication between products of different vendors through translation.
5. Suppose your organization was contemplating switching from a host-based architecture to client-server. What problems would you foresee?
Infrastructure supporting cabling hardware and software will need to be redesigned to support the client-server approach to the architecture. Someone would need to be designated to manage what would now become the local area network, so there may be a personnel impact. Security would be one area of concern, since processing can be done on individual workstations. There may be somewhat greater complexity of upgrades, although newer software is reducing the impact of this kind of problem.
6. Which is less expensive: host-based networks or client-server networks? Explain.
Client-server networks are less expensive because in a competitive market involving multiple vendors, software and hardware upgrades cost substantially less. Upgrades for host-based networks are generally very expensive, and occur in what is generally termed a “step function,” meaning requiring large, discrete steps in expenditure. LANs have the ability to be deployed with a smoother cost curve in less severe increments.
7. Compare and contrast two-tiered, three-tiered, and n-tiered client server architectures. What are the technical differences, and what advantages and disadvantages do each offer?
Two-tiered architectures have only clients and servers.
Three-tiered architectures typical separate (1) presentation logic, (2) application logic, and (3) and data access logic and storage.
In n-tiered architecture more than one tier may be used to support application logic, typically due to a Web server tier being included.
Three-tiered or n-tiered architectures place a greater load on the network, but balances server load better and is more scalable.
8. How does a thin client differ from a thick client?
Thick clients support all or most application logic while thin clients support little or no application logic. Development and maintenance costs for more complex thick-client environments can be higher than for thin clients.
9. What are the benefits of cloud computing?
Benefits include gaining access to experts to manage the cloud, potentially lower costs, scalability, and pay-as-you-g0.
10. Compare and contrast the three cloud computing models.
See Figure 2-7
11. What is a network computer?
A network computer supports Internet access but has no hard disk local storage.
12. For what is HTTP used? What are its major parts?
The standard protocol for communication between a Web browser and a Web server is Hypertext Transfer Protocol (HTTP). An HTTP request from a Web browser to a Web server has three parts. Only the first part is required; the other two are optional.
- the request line, which starts with a command (e.g., GET), provides the URL, and ends with the HTTP version number that the browser understands.
- the request header, which contains a variety of optional information such as the Web browser being used (e.g., Internet Explorer), the date, and a userid and password for use if the Web page is password-protected.
- the request body, which contains information sent to the server, such as information from a form.
The format of an HTTP response from the server to the browser is very similar to the browser request. It has three parts, but only the last part is required; the first two are optional:
- the response status, which contains the HTTP version number the server has used, a status code (e.g., 200 means OK, 404 means page not found), and reason phrase (a text description of the status code)
- the response header, which contains a variety of optional information such as the Web server being used (e.g., Apache), the date, the exact URL of the page in the response body, and the format used for the body (e.g., HTML)
- the response body, which is the Web page itself.
13. For what is HTML used?
HTML is the language in which web pages are created. The response body of an HTTP response can be in any format, such as text, Microsoft Word, Adobe PDF, or a host of other formats, but the most commonly used format is HTML. The major parts of HTML are the heading (denoted by the <head> tag) and the body (denoted by the <body> tag) of the response.
14. Describe how a Web browser and Web server work together to send a Web page to a user.
In order to get a page from the Web, the user must type the Internet Uniform Resource Locator (URL) for the page he or she wants, or click on a link that provides the URL. The URL specifies the Internet address of the Web server and the directory and name of the specific page wanted. In order for the requests from the Web browser to be understood by the Web server, they must use the same standard protocol. The standard protocol for communication between a Web browser and a Web server is Hypertext Transfer Protocol (HTTP).
15. Can a mail sender use a two-tier architecture to send mail to a receiver using a three-tier architecture? Explain.
Yes. With e-mail, users with the two-tier architecture will use the user agent software to interface with their email server, which will send out web based, SMTP packets to the far end receiver’s server computer with mail server software. The server at the far end will issue an IMAP or SMTP packet to the receiver’s server computer, which will then arrive at the receiver when they ask for the email with an HTTP request to the web based email application. Thus, a 2-tiered system easily interfaces with a three-tiered architecture over the internet using the appropriate protocols.
16. Describe how mail user agents and message transfer agents work together to transfer mail messages.
The sender of an e-mail uses a user agent (an application layer software package) to write the e-mail message. The user agent sends the message to a mail server that runs a special application layer software package called a message transfer agent. These agents read the envelope and then send the message through the network (possibly through dozens of mail transfer agents) until the message arrives at the receiver’s mail server. The mail transfer agent on this server then stores the message in the receiver’s mailbox on the server. When the receiver next accesses his or her e-mail, the user agent on his or her client computer contacts the mail transfer agent on the mail server and asks for the contents of the user’s mailbox. The mail transfer agent sends the e-mail message to the client computer, which the user reads with the user agent.
17. What roles do SMTP, POP, and IMAP play in sending and receiving e-mail on the Internet?
SMTP defines how message transfer agents operate and how they format messages sent to other message transfer agents. The SMTP standard covers message transmission between message transfer agents (i.e., mail server to mail server). A different standard called Post Office Protocol (POP) defines how user agents operate and how messages to and from mail transfer agents are formatted. POP is gradually being replaced by a newer standard called Internet Mail Access Protocol (IMAP). While there are several important technical differences between POP and IMAP, the most noticeable difference is that before a user can read a mail message with a POP user agent, the e-mail message must be copied to the client computer’s hard disk and deleted from the mail server. With IMAP, e-mail messages can remain stored on the mail server after they are read.
18. What are the major parts of an e-mail message?
The major parts of an e-mail message are:
- the header, which lists source and destination e-mail addresses (possibly in text form (e.g., “Susan Smith”) as well as the address itself (e.g., smiths@robert-morris.edu)), date, subject, and so on
- the body, which is the message itself.
19. What is a virtual server?
A virtual server is one computer that acts as several servers. Using special software like Microsoft Virtual PC, WMWare, or VirtualBox, several operating systems are installed on the same physical computer so that one computer appears as several different ones on the network.
20. What is Telnet, and why is it useful?
Telnet enables users on one computer to login into other computers on the Internet. Once Telnet makes the connection from the client to the server, a user can login into the server or host computer in the same way as that person would if they dialed in with a modem; the user must know the account name and password of an authorized user. Telnet enables a person to connect to a remote computer without incurring long distance telephone charges.
Telnet can be useful because it enables access to servers or host computers without sitting at the dedicated computer’s keyboard. Most network managers use Telnet to work on their organization’s servers, rather than physically sitting in front of them and using the keyboards.
21. What is cloud computing?
With cloud computing, a company contracts with another firm to provide software services over the Internet, rather than installing the software on its own servers. The company no longer buys and manages its own servers and software, but instead pays a monthly subscription fee or a fee based on how much they use the application.
22. Explain how instant messaging works.
An instant messaging (client) communicates with an IM server application. Once a user is online, the server application can monitor connections so that multiple pre-identified clients can be notified and decide to participate in real-time messaging. IM may include video or audio. Video exchange, of course, requires cameras. Underlying this application requires a full-duplex connection between destination and host.
23. Compare and contrast the application architecture for videoconferencing with the architecture for e-mail.
Videoconferencing must deliver real-time services demanding high capacity data transfer for both image and voice transmission. Specialized hardware (and even rooms) may be required. E-mail messages (typically without large attachments) are relatively small by comparison, can be received by any Internet-capable computer, and do not have to be consumed in real time.
24. Which of the common application architectures for e-mail (two-tier client-server, Web-based) is "best"? Explain.
The best architecture for email can depend on how one wants to use e-mail. If a person wants to be able to access their e-mail from anywhere, then Web-based is best. If the person wants professional backup and storage within an organization, then two-tier client-server is best. If the person wants storage of e-mail strictly under their control and they also want to be able to access their e-mail files off-line when there is a network service interruption, then host-based is best. Employers may choose to use client-server architecture for email access within the organization and Web-based architecture for access to the same system for those times when employees are outside the company (at home, at another business, or on travel).
25. Some experts argue that thin-client client-server architectures are really host-based architectures in disguise and suffer from the same old problems. Do you agree? Explain.
While thin client have substantially less application logic than thick client, they have sufficient application logic (as, for example, a Web browser possibly with Java applets) to participate in a client-server relationship. The older host-based terminals did not even have this much application logic. While thin-client use today reflects some level of return to a more centralized approach, the client is likely served by multiple servers (and even multiple tiers), rather than a single large host server as in the past. Thus, the two approaches are similar, but not exact, from a technological design perspective.
Mini-Cases
I. Deals-R-Us Brokers (Part 1)
Fred's information systems department has presented him with two alternatives for developing the new tools. The first alternative will have a special tool developed in C++ that clients will download onto their computers to run. The tool will communicate with the DRUB server to select data to analyze. The second alternative will have the C++ program running on the server; the client will use his or her browser to interact with the server.
a) Classify the two alternatives in terms of what type of application architecture they use.
b) Outline the pros and cons of the two alternatives and make a recommendation to Fred about which is better.
The alternatives are shown in the text as Figures 2-2 (client-based) and 2-3 (two-tier client-server).
Client-based is simple; however all data must travel to the client for processing, thus giving the potential for speed delays over the network.
Client-server provides processing on the server, which could be an advantage if the data to be processed also resides on the server; yet, because it involves heterogeneous software, this can be a significant disadvantage in terms of interoperability.
II. Deals-R-Us Brokers (Part 2)
Dears-R-Us Brokers has decided to install a new e-mail package. One vendor is offering an SMTP-based two-tier client server architecture. The second vendor is offering a Web-based e-mail architecture. Fred doesn't understand either one, but thinks the Web-based one should be better because, in his words "the Web is the future."
a) Briefly explain to Fred, in layman's terms, the differences between the two.
b) Outline the pros and cons of the two alternatives and make a recommendation to Fred about which is better.
a) If they host the email in-house using Microsoft Exchange Server, this means that they purchase a physical computer to use as a mail server and install Microsoft Server as the operating system. Then, they will need to install the Microsoft Exchange Server software which will allow the server to be used as a mail server. The network administrator at DRUB can then configure and manage the email user accounts, etc himself. The second solution is to use one of the cloud-based providers and completely outsource the company email. Two examples are Gmail and GoDaddy. With each of these services, the DRUB will pay a monthly fee for one of the providers to configure and manage the mail servers for them.
b) Each of these options has their advantages and disadvantages. A few of these include:
In-house advantages: control, potentially lower cost
In-house disadvantages: more work to do, potentially less expertise available
Outsourcing advantage: potentially lower cost, better service, less work to do in-house
Outsourcing disadvantages: loss of control, potentially higher costs
III. Accurate Accounting
Accurate Accounting managing partner Diego Lopez asks: Why can’t IM work as simply as e-mail? Will the new videoconferencing software and hardware work as simply as e-mail, or will it be IM all over again? Prepare a response to his questions.
E-mail standards enable it to be used easily between companies. Lack of IM standards means that several competing protocols exist. This problem will be overcome as commercial interests push for standardization or development of middleware that enables disparate systems to talk to one another. The same pattern of innovation will likely happen that is typical of all new technologies. At present, there are large corporate concerns over the security aspects of externally based IM software deployments within an organization’s boundaries, limiting the use of IM packages in some organizations until these concerns are mitigated.
IV. Ling Galleries
How can the Internet help gallery owner Hoard Ling with his two new galleries?
There are a variety of ways the Internet could help Mr. Ling. He could develop a website where his paintings would be featured and some additional information about the artist would be displayed for potential buyers to learn and explore more about the works. Further, the website could include an e-commerce function whereby visitors would be able to order prints of paintings they like. The site could help Mr. Ling track customer tastes so that he can better understand the types of paintings that sell well, thus allowing the business to develop while matching future production to the strongest market for the paintings.
Next Day Air Service Case Study
1. Prepare a brief management summary on the technical essential aspects of the Internet and the World Wide Web and how they work. Remember, the audience is not technical. He is confused about the relationship between the World Wide Web and the Internet and often states that they are the same. Please be sure to explain this in your summary.
One thing to remember and to emphasize with your students is the point that this question brings out, namely that there is great confusion between what constitutes the Internet and what exactly is the World Wide WEB. The majority of my students are surprised to learn that there is a major difference. The answer is simple, one is the physical layer, hardware nuts & bolts that makes up the highway upon which network traffic will flow. The other (WWW) is but one, albeit now the largest, applications that are available to run over the Internet.
The Internet actually began without the WWW. It was a bit level, text based network that evolved in a largely DOS based world. For the most part, from its inception it required the TCP/IP protocol suite to be running on the source and destination hosts that were interoperating as we use to refer to it back in those days. As WINDOWs and the graphical user interface evolved so did the ways that we used the Internet.
In the early 90’s after a few years of using, testing and refining several other GUI applications to support Internetworking, the WWW application became standardized along with a few new protocols which were added to the TCP/IP protocol suite. These included HyperText Transfer Protocol now known simply as HTTP and Domain Name Server, now simply known as DNS.
2. President Coone is particularly intrigued with the potential of the Internet, but he and the other members of management are not exactly sure what or how NDAS can use them to improve its competitive edge. Present some alternatives. President Coone reminds you that NDAS expects to enlarge its scope in the international market. Plans call for first offerings to be services to Britain, France, and Germany, with later expansion to South America. President Coone wants you to involve Bob Jones in your work on the Internet.
The Internet is global these days. Carrier access providers, known as ISPs, can provide a company like NDAS with a number of network transport options to connect each of their sites, both domestic and international to the Internet. Once connected there are many applications that NDAS could consider. NDAS could put in place an Intranet at their headquarters. Each of the other sites could access any of t he applications running on the Intranet via the Internet. NDAS could for example have a standard Email application system and make this available to everyone in the company. NDAS could develop a WEB Site for its employees as well as its customers and suppliers to access via the Internet. It is common these days for companies to do this. The type of WEB Site applications typically can run from simple apps like providing essential information about the company to having elaborate back end database applications supporting things like order entry and making electronic payments.
The Marketing departments of companies these days are involved in the development of corporate WEB Sites because of the tremendous reach that a WEB Site can have in the marketplace. As such, Bob Jones’ department should be consulted and have representation in the WEB Site development process. The image projected by the quality of the WEB Site will be a critical factor to its success. Bob Jones’ department has the expertise to lend in making sure that the WEB Site adequately represents the NDAS corporate image.
3 . With the updates planned for the network , President Coone wonders what other benefits could be derived from the network . One that he particularly is intrigued by is video-conferencing. Explain to him in a memo how the video-conferencing could be beneficial.
The students should create a memo addressed to President Coone that includes some of these main benefits of video-conferencing:
Decreased travel time
Decreased travel expenditures
Better communication (relative to phone)
Additional Content
Teaching Notes
I usually spend 3 hours of class time on this chapter.
I also include hands-on labs on (1) HTML (using Microsoft Word, Front Page, or Dreamweaver) to ensure that all students can create their own web pages and (2) FTP (using both a graphic-interface FTP application and command line FTP access) to ensure that students can transfer files. Sometimes I include a hands-on Web and e-mail lab as well.
I have several goals when I teach this chapter. First, I want students to get a sense of the history of the Internet beyond what they already know. Most of my students think the Internet has always been there. The “traditional” history given in Introduction to Computing courses usually mentions that the Internet started in the late 1960s. This is true, but can be misleading; it implies the Internet has always been an important network. I try to show how small it was at first and illustrate that that it was only one of several possible networks that could have “won.” I also try to impress upon them the extremely rapid growth in the past few years. You might want to update the timeline with more recent statistics on the number of Internet users. See www.boardwatch.com. It is useful to explain that the Internet was not originally designed for commercial activities, and that this lack of a business intent carries over into some of the more difficult aspects of traffic management and control in today’s environment.
I have two goals for the Internet applications section. First, I want students to become familiar with the Web, SMTP, FTP, and telnet, although for most students this is remedial. Starting with this material, however, helps students to understand the importance and relevance of the course – everyone wants to learn more about the Internet.
The Internet applications discussion is also a good place to explain exactly what is meant by standards and layers from Chapter 1. The HTTP/SMTP standards help students understand why we need standards and most importantly that there are standards at all layers in the network model. This underscores the concept that each layer is distinct and has a packet within a packet within a packet, something I have always found that students have difficulty understanding. In my opinion, this concept is more important than having them memorize the contents and format of each type of packet, although I require them to be able to explain the parts of the packet and what each does.
Electronic commerce is an important topic. Most students want to learn about it, and many have been exposed to it in prior classes. I cover enough to help them sort out what is going on the Web with respect to the use of the Internet to operate the back end of businesses using electronic commerce. I also try to link the material to their marketing or economics courses. We discuss aspects of purchasing goods over the internet, and I also ask them if they have purchased anything over the web, used instant messaging or else used desktop videoteleconferencing. Most students have done so, and they are interested in this chapter because it begins their understanding of the nuts and bolts of how web pages and web site forms might be transmitted over networks.
War Stories
Electronic Commerce and Prices
(Objective: Illustrate the implications of electronic commerce for today’s businesses; The potential is immense).
A friend of mine recently decided to get a car loan for a new car. After checking out Edmund’s (www.edmunds.com) for information, he clicked on the link to a car loan firm. The loan quote was 7.70%. He then called his bank and USAA (a large financial organization well known for offering cheap loans to U.S. veterans). Neither could match the loan rate, although USAA came the closet at 7.85%. Neither would match the Internet rate, even though he had extensive ties to both. It turns out the company offering the low rates on the Internet was actually his bank, doing business under a different name. Electronic commerce has vast implications for business, and this chapter is about the technical underpinnings of how this information moves around the internet.
I usually describe my first experiences with e-mail, which were before the days of the Internet. You may also have some good e-mail war stories. The objective is to reinforce the changes in technologies; the Internet hasn’t always been dominant. Sometimes I cite an alternative e-mail technology, the US Veterans Affairs (VA) FORUM, the VA's national electronic mail system. Electronic discussions, conferences, distribution of VA directives, news, and computer programs are its primary functions. FORUM disseminates information across any communications medium and also hosts several national databases. Because VA FORUM works according to e-mail threads, it has been extensively used to document the process of software development in the VA health care system.
Chapter 2
Application Layer
True-False Questions
The following are possible True/False questions for tests. The statement is given and the answer is provided. The level of difficulty (easy, medium, hard), the reference section relevant to the topic, and learning objective are also furnished.
| 1. | An application architecture is the way in which the functions of the application layer are performed solely by the clients in the network. Answer: False Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 2. | The four general functions of any application program are: data storage, data access logic, application logic and presentation logic. Answer: True Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 3. | A server farm is a group of computers that are linked together so they act as a one computer. Answer: True Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 4. | Host-based and client-based networks are similar in that the client computer performs most of the work. Answer: False Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 5. | The earliest data communications networks were client-server networks. Answer: False Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 6. | As the demand for more and more network applications grow; host-based computing becomes the best solution. Answer: False Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 7. | One major drawback to a client-server network lies in the fact that client-server networks enable software and hardware from different vendors to be used together. Answer: False Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 8. | In a client-server network, the presentation logic is the responsibility of the client computer. Answer: True Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 9. | The two functions of middleware are to: 1) provide a standard way of communicating that can translate between software from different vendors, and 2) manage the message transfer between clients and servers so that clients do not need to ‘know’ which server contains the application’s data. Answer: True Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 10. | Middleware is the software that sits between the application software on the client and the application software on the server. Answer: True Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 11. | In the three-tier architecture, the software on the client computer is responsible for the presentation logic, an application server is responsible for the application logic and a separate database server is responsible for the data access logic and data storage. Answer: True Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 12. | A “thin client” approach places most of the application logic on the client. Answer: False Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 13. | The application architecture called the distributed computing model uses the “thick” client approach. Answer: False Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 14. | Scalability refers to the ability to increase or decrease the capacity of the computing infrastructure in response to changing capacity needs. Answer: True Difficulty: Easy Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 15. | To use the Web, each client computer requires a data link layer software package called a Web browser. Answer: False Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 16. | The standard protocol for communication between a Web browser and a Web server is the web protocol. Answer: False Difficulty: Medium Reference: World Wide Web L.O.: Understand how the Web works |
| 17. | The World Wide Web was conceived at University of Utah as part of the development of the Internet. Answer: False Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 18. | A request header for an HTTP request starts with a command, such as GET, and ends with the HTTP version number that the browser understands. Answer: False Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 19. | All three parts (request line, request header, request body) of an HTTP request from a web browser to a web server are required when a request is made. Answer: False Difficulty: Medium Reference: Electronic Mail L.O.: Understand how email works |
| 20. | The Simple Mail Transfer Protocol is the least commonly used e-mail standard. Answer: False Difficulty: Easy Reference: Electronic Mail L.O.: Understand how email works |
| 21. | The two-tier e-mail architecture does not require any application software on the client computer. Answer: False Difficulty: Easy Reference: Electronic Mail L.O.: Understand how email works |
| 22. | Using the POP standard for client to server e-mail communication, the e-mail messages remain on the server computer. Answer: False Difficulty: Easy Reference: Electronic Mail L.O.: Understand how email works |
| 23. | Web-based e-mail like Hotmail is an example of three-tier client-server architecture that provides access to e-mail messages.
Answer: True Difficulty: Medium Reference: Electronic Mail L.O.: Understand how email works |
| 24. | The fundamental problem in client-based networks is that all data on the server must travel to the client for processing Answer: True Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 25. | Cloud computing is now available on the client side (i.e. the desktop). Answer: True Difficulty: Medium Reference: Application Architectures L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
MULTIPLE CHOICE
The following are possible multiple-choice questions for tests. The question is posed and the answer is provided under the choices. The level of difficulty (easy, medium, hard), the reference section relevant to the topic, and learning objective are also furnished.
| 1. | A(n) __________ is the way in which the functions of the application layer software are spread among the clients and servers in the network.
Answer: D Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 2. | A ________ is a very large general-purpose computer that is capable of performing very many functions as if these are done simultaneously, and storing extremely large amounts of data. a. workstation b. transaction terminal c. cluster d. mainframe e. personal computer Answer: D Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 3. | A ________ is a group of computers linked together so that they act as one computer.
Answer: C Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 4. | With the two-tier client-server architecture, the server is responsible for the ________ logic. a. application b. presentation c. data access d. session e. physical Answer: C Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 5. | Which of the following is not a general function by any application program? a. data storage b. data access logic c. application logic d. presentation logic e. application access storage Answer: E Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 6. | _________ is an application program function that deals with storing and retrieving data. a. data storage b. data access logic c. application logic d. presentation logic e. application access storage Answer: A Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 7. | An application program function is __________, or the processing required to access data.
Answer: B Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 8. | ______________, or the algorithms or business logic programmed into the application, can be simple or complex depending on the application.
Answer: C Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 9. | ________ is the presentation of information to the user and the acceptance of the user’s commands.
Answer: D Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 10. | One underlying problem with a host-based network is that: a. there are economies of scale because all computer resources are centralized b. the server can get overloaded since it must process all messages c. the architecture is relatively simple and works well d. the server is the one point of control which simplifies security e. clients (terminals) do not require sophisticated hardware/software because they do not perform most of the work in this type of architecture Answer: B Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 11. | With a client-based network, one fundamental problem is that:
Answer: D Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 12. | With the two-tier client-server architecture, the client is responsible for the ________ logic. a. session b. presentation c. data access d. data storage e. networking Answer: B Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 13. | Client-server architectures: a. cannot connect computers that use different hardware b. are one of the least used network architectures today c. can use middleware to provide a standard way of communicating between software from more than one vendor d. assign the responsibility for the presentation logic to the server e. were the earliest type of network architectures Answer: C Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 14. | How are the application architecture functions split up in a client-server network? a. the presentation logic and data storage are on the client, while the data access logic is on the server b. the data storage, data access, and presentation logic are on the client c. the presentation logic is on the client, while the data storage and data access logic are on the server d. the data storage and data access logic are on the client, while the presentation logic are on the server e. the presentation logic and data access logic are on the client, and the data storage is on the server Answer: C Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 15. | In a client-server network, _________ gets software from different vendors to work together. a. a front-end processor b. serverware c. middleware d. centerware e. programmer Answer: C Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 16. | ____________ is not an important middleware standard. a. CORBA (Common Object Request Broker Architecture b. Distributed Computed Environment (DCE) c. Asynchronous Transfer Mode (ATM) d. Open Database Connectivity (ODBC) e. none of the above is an appropriate answer Answer: C Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 17. | A(n) _________-tiered architecture uses only two sets of computers: one set of clients and one set of servers.
Answer: B Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 18. | In the three tier architecture the software on the client computer is responsible for____________.
Answer: A Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 19. | An N-tiered architecture: a. is generally more “scalable” than a three-tiered architecture b. is generally less “scalable” than a three-tiered architecture c. uses only two sets of computers in which the clients are responsible for the application and presentation logic, and the servers are responsible for the data d. uses exactly three sets of computers in which the client is responsible for presentation, one set of servers is responsible for data access logic and data storage, and application logic is spread across two or more different sets of servers e. puts less load on a network than a two-tiered architecture because there tends to be less communication among the servers Answer: A Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 20. | One disadvantage of the ____________ architecture is that places a greater load on the network.
Answer: D Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 21. | A “thin client” architecture approach:
Answer: D Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 22. | A “thick client” architecture approach:
Answer: C Difficulty: Easy Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 23. | With the “thin client” architecture, when an application changes, only the _________ with the application logic needs to be updated. a. client b. server c. middleware d. hardware e. software Answer: B Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 24. | With respect to costs for a client-server network, which of the following is true? a. Personal computers used as clients in a client-server network cost about the same as mainframes for the same amount of computing power. b. More network capacity, which costs more money, is required for client-server networks than for client-based networks. c. Experts believe that client server architectures can be complex, but that developing application software for host based architectures is usually cheaper. d. Updating the network with new version of software tends to be less expensive in a client-server network since the software is centralized in one client. e. None of the above Answer: C Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 25. | The idea for a special hypertext network, called the World Wide Web, was conceived of by: a. Microsoft in 1994 as part of the Windows 95 project b. Tim Berners-Lee at the European Laboratory for Particle Physics (CERN) in 1989 c. Vinton Cerf, for the U.S. Department of Defense in 1969 as a network of four computers called ARPANET d. Howard Flieshman of IBM in 1982 as part of the development of the IBM PC e. the University of Minnesota as an extension of Gopher Answer: B Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 26. | Marc Andreessen led a team that developed the first graphical Web browser, which was called: a. Internet Explorer b. Mosaic c. Firebird d. Netscape Navigator e. Mozilla Answer: B Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 27. | To interact with the World Wide Web, a client computer needs an application layer software package called a: a. Web browser b. Web server c. Telnet package d. Uniform Resource Locator package e. Router package Answer: A Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 28. | Each server on a network that needs to act as a web server needs an application layer software package called a (n) ______________.
Answer: C Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 29. | To get a page from the Web, a user must type in a URL, which stands for: a. Unknown Resource Locator b. Unknown Router Location c. Uniform Router Location d. Uniform Resource Locator e. Uniform Resource Library Answer: D Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 30. | The protocol that makes it possible for a Macintosh web browser to be able to retrieve a Web page from a Microsoft Web server is called _____________________. a. Hypertext Transfer Protocol b. File Transfer Protocol c. Simple Mail Transfer Protocol d. Internet Message Access Protocol e. Hyperlink Transfer Protocol. Answer: A Difficulty: Medium Reference: World Wide Web L.O.: Understand how the Web works |
| 31. | There are optional and required parts of an HTTP request. They are:
Answer: E Difficulty: Medium Reference: World Wide Web L.O.: Understand how the Web works |
| 32. | There are required and optional parts of an HTTP response. They are: a. response status, response header, response body b. response address, response header, response body c. response status, response body d. response address, response header e. response status, response header Answer: A Difficulty: Medium Reference: World Wide Web L.O.: Understand how the Web works |
| 33. | A response status code of 404 means: a. the requested page was not found b. the server is currently unavailable c. the sever is currently busy d. your browser is incompatible with the Web server software. e. your browser needs to be updated to the latest version. Answer: A Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 34. | The acronym, HTML, refers to: a. Header Markup Language b. Hypertext Markup Locator c. Hypertext Markup Language d. Hypertext Markup Library e. Hypertext Modulating Language Answer: C Difficulty: Easy Reference: World Wide Web L.O.: Understand how the Web works |
| 35. | Which of the following is not an advantage of instant messaging? a. It usually takes days for an IM message to be delivered to the recipient. b. It allows real time typed messages to be exchanged. c. Some products are ICQ and AOL Instant Messenger. d. It is generally faster than snail-mail. e. It helps people avoid telephone tag. Answer: A Difficulty: Easy Reference: Other Applications L.O.: Be aware of how Telnet and instant messaging works |
| 36. | The most commonly used e-mail standard is: a. Simple Mail Transfer Protocol b. X.400 c. CMC d. Post Office Protocol e. Telnet Answer: A Difficulty: Easy Reference: Electronic Mail L.O.: Understand how email works |
| 37. | In a two-tier client-server architecture, a client computer needs to use an application layer software package called a ________________ to send e-mail: a. message transfer agent b. router agent c. user agent d. Webcast package e. gateway agent Answer: C Difficulty: Medium Reference: Electronic Mail L.O.: Understand how email works |
| 38. | Which of the following is not a user agent package? a. Outlook Express b. Microsoft Word c. Eedora d. All of these are user agent packages e. Microsoft Outlook Answer: B Difficulty: Medium Reference: Electronic Mail L.O.: Understand how email works |
| 39. | Another term for a user agent is:
Answer: C Difficulty: Easy Reference: Electronic Mail L.O.: Understand how email works |
| 40. | IMAP (Internet Message Access Protocol): a. is a set of standards that define how email is to be processed between mail servers b. is exactly the same as SMTP c. copies an e-mail message from the client computer’s hard disk, deletes it from the client, and stores it on the mail server d. is exactly the same as POP e. permits an e-mail message to remain stored on the mail server even after they have been read by a client computer
Answer: E Difficulty: Easy Reference: Electronic Mail L.O.: Understand how email works |
| 41. | In a ___________ architecture, computers are both client and server, thus sharing the work.
Answer: D Difficulty: Medium Reference: Application Architectures L.O.: Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures |
| 42. | The acronym, MIME, refers to: a. Multimedia Internet Mail Enterprise b. Multiple Internet Media Extension c. Multipurpose Internet Mail Extension d. Media Internet Mail Extension e. Multimedia Internet Mime Extension
Answer: C Difficulty: Easy Reference: Electronic Mail L.O.: Understand how email works |
| 43. | One of the most frequently used Telnet applications is
Answer: B Difficulty: Medium Reference: Other Applications L.O.: Be aware of how Telnet and instant messaging works |
| 44. | The fastest growing form of videoconferencing is a. mainframe b. Outlook c. Telnet d. webcasting e. desktop
Answer: E Difficulty: Medium Reference: Other Applications L.O.: Be aware of how Telnet and instant messaging works |
| 45. | Which of the following is not true about Telnet? a. Telnet requires an application layer program on the client computer and an application layer program on the server or host computer. b. Telnet poses no security threat. c. Telnet was designed in the early days of the Internet. d. You are using a host-based architecture with Telnet. e. One program that conforms to the Telnet standard is EWAN.
Answer: B Difficulty: Medium Reference: Other Applications L.O.: Be aware of how Telnet and instant messaging works |
| 46. | _________ is a special type of one directional; videoconferencing in which content is sent from the server to the user. a. broadcasting b. instant messaging c. webcasting d. H.323 e. Net Meeting.
Answer: C Difficulty: Medium Reference: Other Applications L.O.: Be aware of how Telnet and instant messaging works |
47. In a host-based system with a mainframe, upgrades to the host are _____________.
a. Small
b. Cheap
c. Lumpy
d. Never going to happen
- Always performed annually
Answer: C
Difficulty: Easy
Reference: Application Architecture
L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures
- The software that runs on the mail server is referred to as the ____________
- Mail transfer agent
- Mail user agent
- Microsoft Outlook
- Web server
- SMTP
Answer: A
Difficulty: Easy
Reference: Electronic Mail
L.O.: Understand how email works
- The standards H.320, H.323, and MPEG-2 are commonly used with
- Telnet
- Videoconferencing
- IM
- Microsoft Office
Answer: B
Difficulty: Medium
Reference: Other Applications
L.O.: Be aware of how Telnet and instant messaging works
50. The ________________ cloud deployment model provides the highest levels of control, privacy and security.
a. private
b. public
c. community
d. hybrid
Answer: A
Difficulty: Easy
Reference: Application Architecture
L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures
51. The ________________ clouds realize the benefits from cloud infrastructure (such as speed of deployment) with the added level of privacy and security that private clouds offer.
a. private
b. public
c. community
d. hybrid
Answer: C
Difficulty: Easy
Reference: Application Architecture
L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures
52. With ______________, the cloud provider manages the hardware including servers, storage, and networking components. The organization is responsible for all the software, including operating system (and virtualization software), database software, and its applications and data.
a. private clouds
b. hardware clouds
c. storage services
d. IaaS
Answer: D
Difficulty: Easy
Reference: Application Architecture
L.O. : Understand host-based, client-based, client-server, cloud-based, and peer-to-peer application architectures
Essay and Short Answer Questions
1. Describe the history of the Internet and the Web (part of this is in Chapter 1, part in Chapter 2). Where do you forsee the future evolution of the Internet heading, and why?
2. What do the following tools enable you to do: the Web, email, Telnet, IM?
3. How can the Internet be used for competitive advantage in business? Describe three firms which are using the Internet for conducting business, and speculate as to the underlying technologies which might be in use in these firms. Will the Internet become an essential business tool like the telephone or will it go the way of the dinosaurs? What do you envision the Internet and web becoming in the future for businesses? Discuss.
4. For what is HTTP used? What are its major parts? Are all required?
5. For what is HTML used? What are its major parts? Are all required?
6. Describe how a Web browser and Web server work together to send a web page to a user.
7. Describe how mail user agents and message transfer agents work together to transfer mail messages, including a diagram.
8. Describe the difference between a two tier and three tier email message transfer, using diagrams and discussing how this approach differs from the two layer email transfer. Do users always require the same architecture for email? Why or why not? Discuss.
9. What is MIME? What does it stand for? Why was it developed?
10. What are the standards SMTP, POP, and IMAP? What roles do SMTP, POP, and IMAP play in sending and receiving email on the Internet? What do these acronyms stand for?
11. What are the major parts of an email message?
12. What is X.400 and CMC?
13. What is cloud computing and how is it useful?
14. What is Telnet and why is it useful?
15. What is IM? How does it work?
17. Discuss the functions of a web browser. Describe two web browsers. What was the first graphical Web browser? What are three search engines that you might use to find information on the Internet?
18. What are the three major parts of an HTTP request and what information does each part contain? Why does HTTP include a version number as part of the packet?
19. What do a user agent and message transfer agent do in an SMTP/IMAP email system? What are some examples of user agent packages?
20. Describe a two-tier, three-tier and n-tier architecture. What is a network architecture? Compare and contrast two-tiered, three-tiered, and n-tiered client server architectures. What are the technical differences and what advantages and disadvantages do each offer? How does a two-tier client server network differ from an n-tier client server network. Describe one advantage and one disadvantage that a three-tier architecture has compared to a two-tier architecture.
21. What are the advantages and disadvantages of host-based networks versus client-server networks? Explain two major benefits and/or limitations of client-server networks compared to host-based networks.
22. What is middleware and what does it do?
23. Suppose your organization was contemplating switching from a host-based architecture to client-server. What problems would you foresee?
24. Compare private, public, and community cloud architectures.
No comments:
Post a Comment