Business Data Communications and Networking 11e FitzGerald solutions manual and test bank

 Business Data Communications and Networking 11e FitzGerald solutions manual and test bank

Business Data Communications and Networking, 11th Edition

by Jerry FitzGerald

ISBN 978-1-118-08683-4

August 2011, ©2012

http://www.mediafire.com/view/wgkhvxt00l7x6vw/Business_Data_Communications_and_Networking_11e_FitzGerald_solutions_ch02.doc

http://www.mediafire.com/view/gks373qwqi3u87t/Business_Data_Communications_and_Networking_11e_FitzGerald_tbc2.doc

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 in square brackets. The level of difficulty (easy, moderate, difficult) and the page number(s) relevant to the topic 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: Moderate             Reference: 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
3.	A cluster is a group of computers that are linked together so they act as a one computer.   Answer: True                        Difficulty: Easy                     Reference: Technical Focus
4.	A network computer is designed primarily to communicate using Internet based standards, but has no hard disk.  It has only limited functionality. Answer: True                        Difficulty: Easy                     Reference: Technical Focus
5.	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
6.	The earliest data communications networks were client-server networks. Answer: False                      Difficulty: Easy                     Reference: Host-Based Architectures
7.	As the demand for more and more network applications grow; host-based computing becomes the best solution. Answer: False                        Difficulty: Moderate             Reference: Host-Based Architectures
8.	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: Moderate             Reference: Client-Server Architectures
9.	In a client-server network, the presentation logic is the responsibility of the client computer. Answer: True                      Difficulty: Easy                     Reference: Client-Server Architectures
10.	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: Moderate             Reference: Client-Server Architectures
11.	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: Client-Server Architectures
12.	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: Moderate             Reference: Two-Tier, Three Tier, and n-Tier Architectures
13.	A “thin client” approach places most of the application logic on the client. Answer: False                       Difficulty: Easy                     Reference: Thin Clients versus Thick Clients
14.	The application architecture called the distributed computing model uses the “thick” client approach. Answer: False                       Difficulty: Moderate             Reference: Thin Clients versus Thick Clients
15.	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: Scalability Chapter 2: Application Layer 11th edition Chapter Outline INTRODUCTION APPLICATION ARCHITECTURES        Host-Based Architectures        Client-Based Architectures        Client-Server Architectures        Peer-to-Peer Architectures        Choosing Architectures WORLD WIDE WEB        How the Web Works        Inside an HTTP Request        Inside an HTTP Response ELECTRONIC MAIL        How E-Mail Works        Inside an SMTP Packet Attachments in Multipurpose Internet Mail Extension OTHER APPLICATIONS        Telnet        Instant Messaging        Videoconferencing IMPLICATIONS FOR MANAGEMENT SUMMARY 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; even though electronic commerce is still fairly new today, 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.  E-mail 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. Answers to End-of-Chapter Questions 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 is a network computer? A network computer supports Internet access but has no hard disk local storage. 11.  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.