New Perspectives on Computer Concepts 2011 Instructor’s Manual of
Chapter Six: The Internet
A Guide to this Instructor’s Manual:
We have designed this Instructor’s Manual to supplement and enhance your teaching experience through classroom activities and a cohesive chapter summary.
This document is organized chronologically, using the same heading in blue that you see in the textbook. Under each heading you will find (in order): Lecture Notes that summarize the section, Figures and Boxes found in the section (if any), Teacher Tips, Classroom Activities, and Lab Activities. Pay special attention to teaching tips, and activities geared towards quizzing your students, enhancing their critical thinking skills, and encouraging experimentation within the software.
In addition to this Instructor’s Manual, our Instructor’s Resources CD also contains PowerPoint Presentations, Test Banks, and other supplements to aid in your teaching experience.
For your students:
Our latest online feature, CourseCasts, is a library of weekly podcasts designed to keep your students up to date with the latest in technology news. Direct your students to http://coursecasts.course.com, where they can download the most recent CourseCast onto their mp3 player. Ken Baldauf, host of CourseCasts, is a faculty member of the Florida State University Computer Science Department, where he is responsible for teaching technology classes to thousands of FSU students each year. Ken is an expert in the latest technology and sorts through and aggregates the most pertinent news and information for CourseCasts so your students can spend their time enjoying technology, rather than trying to figure it out. Open or close your lecture with a discussion based on the latest CourseCast.
061600 FTP makes it easy to anonymously use a search engine. (Answer: False) (336)
061700 BitTorrent is an Internet security protocol. (Answer: False) (338)
061800 Consumers should use port probes to encrypt data sent over the Internet. (Answer: False) (341)
061900 NATs are used by hackers to intercept packets traveling over the Internet. (Answer: False) (344)
SECTION A: INTERNET TECHNOLOGY
SECTION A OPENER QUESTION:
062100 One reason the Internet works is because TCP/IP offers a global addressing standard. Which one of the following is accurate in the context of Internet addresses?
IPv6 addresses such as 22.214.171.124 are dedicated to educational institutions.
Top level domains like EarthLink or AOL are adequate for most consumers.
A domain name, such as amazon.com corresponds to a unique IP address.
A dynamic IP address begins with www.
Inform students that the Internet evolved from an experimental network called ARPANET, which was developed in 1969 to help scientists communicate and share computing resources.
Note that the Internet is estimated to have 500 million nodes and more than 1.5 billion users. It also handles more than 1 exabyte of data per day. This is a good place to discuss what an exabyte is (1.074 billion gigabytes) and just how large that is.
Assign a Project: To get a handle on just how large the Internet is, have the students perform research on how much data is in the Library of Congress or their own library.
Internet Infrastructure (303)
Use Figure 6-2 to discuss network access points and network service providers. Do the companies that run these (Sprint and Verizon, for example) “own” the Internet? Make sure students understand why this is not true.
Explain that Internet service providers operate hardware and software that enable users to connect to the Internet. These include modem banks, e-mail servers, and devices like domain name servers.
Use the diagram in Figure 6-3 to discuss hardware.
Discuss Figure 6-4 with the students and discuss the various hardware components and where they might be found. For example, a modem may be built into their laptop and they don’t see it but it is there just the same.
Figure 6-2, Figure 6-3, Figure 6-4
Assign a Project: Ask students to create a sketch illustrating their Internet connection. Tell them to be sure to include their ISP in the sketch. Have them identify where each component may be found. Where is their ISP located? Where is their NSP located? See if they can research and find this information.
A(n) _______ contains circuitry that converts the data-carrying signals from your computer to signals that can travel over various communications channels. (Answer: modem)
The ___________ is a network of high-capacity communications links that provides the main routes for data traffic across the Internet. (Answer: Internet backbone)
NSP equipment and links are tied together by what? (Answer: Network access points or NAPs)
Internet Protocols, Addresses, and Domains (305)
Define a protocol.
Explain that TCP/IP is the protocol of the Internet.
Use Figure 6-5 to discuss other Internet protocols such as HTTP and FTP.
Explain the difference between IP addresses and domain names.
Look at some IP addresses in context. You can examine the properties of an e-mail message to find the IP addresses of the servers that transferred the message from one destination to another. In Microsoft Outlook, for example, right-click a message and then click Options to open the Message Options dialog box. Scroll through the Internet headers to see the IP addresses of the servers that handled the e-mail messages.
Explain that students don’t need to know their IP address to check e-mail, surf the Web, or do any of their usual activities.
Use Figure 6-7 to discuss top-level domains. You can have students research top-level domains to discover which names have been proposed in addition to the ones listed in Figure 6-7.
Go over the relationship between IP addresses and domain names, and the role of the domain name server.
Review the difference between domain names and URLs. A URL is an Internet address of a document on a computer, whereas a domain name is the IP address of a computer.
Visit www.register.com to learn how to select and register a domain name. Figure 6-9 illustrates this process.
Be sure and discuss the difference between dynamic and static IP address. Go over why you would use each. Discuss what happens when you use dial-up in term of IP addresses.
Go to several Internet addresses with different top-level domains. Go to some outside the country such as Canada and the United Kingdom. Examine the relationship between the domain name and the IP address to show that there is no relationship.
Explain that computers on the Internet know where to send a packet of data by using the IP address of its destination. At each intersection on the backbone, the data’s IP address is examined by a router, which forwards the data towards its destination.
Discuss the factors that may affect the speed of your Internet connection.
Describe the Ping and Traceroute utilities.
Assign a Project: Have the students do their own ping. On page 301, the second page of this chapter, there is a Try It section on how to use ping. Have the student do this exercise as well as ping the school Web page and compare the times. Discuss why the times are different.
Assign a Project: Have the student do a Traceroute like the one on page 310.
SECTION B: FIXED INTERNET ACCESS
SECTION B OPENER QUESTION:
062200 Although ISPs offer Internet access though dial-up, satellites, WiMAX, ISDN, and DSL, cable Internet is currently the preferred access method. Why?
It is the least expensive.
It is the fastest and most widely available technology.
It has the highest latency.
It was the original Internet access technology.
Dial-up Connections (312)
Discuss how dial-up connections take place.
Many students wonder why some pages load more quickly than others do, or why some sites seem slower during certain times of the day when the speed of their modem remains constant. Review with students the difference between connection speed and transfer rate, and discuss the reasons why data is not always transferred at their modem’s highest speed.
Discuss the difference between analog and digital. Use a digital and analog clock to show the difference.
Discuss the function of the modem. Use Figure 6-12 to demonstrate. Explain that the computer is digital and cannot use analog signals. Use the idea that a light switch cannot be half on. It must be either on or off.
Figure 6-11, Figure 6-12, Figure 6-13
Class Discussion: Ask students if they have experience using a dial-up connection. How does its performance compare to other connections?
DSL, ISDN, and Dedicated Lines (314)
Discuss digital technology. The advantage these connection lines offer is that they are completely digital, so data does not have to be converted from analog to digital as it does when you use a dial-up connection.
Discuss the difference between a modem and a terminal adapter. Make the point that adapters do not change the signals from digital to analog and vice versa.
Note the simultaneous use of voice and data. You can be connected to the Internet, and still talk on the telephone.
Explain that although ISDN lines can be affordable, they are most often used by businesses with small LANs. ISDN connections are also faster than a dial-up connection, but not as fast as DSL or cable modems. Find out if ISDN is available to customers in your area.
Describe how DSL works.
Discuss the speed of DSL.
Point out that DSL installations typically require a modem and filters.
Figure 6-14, Figure 6-15, Figure 6-16
Class Discussion: What types of Internet connections are available to students? If students are not already aware of the fact that not all types of connections are available in all locations, point that out. Have students compare the performance of different Internet connections they’ve used.
What does DSL stand for? (Answer: digital subscriber line)
____ is a high-speed, digital, always-on, Internet access technology that runs over standard phone lines. (Answer: DSL)
True/False: You need a modem to use ISDN. (Answer: False)
Cable Internet Service (316)
Use Figure 6-18 to go over how to set up a cable modem connection.
Explain that many cable TV companies are also Internet service providers, although they will usually only provide service to those who also utilize their cable TV services. Since most communities have only one major cable provider, your local provider choices may be limited.
Discuss the pros and cons of dial-up and cable modem connections. For example, what advantages does the cable modem’s always-on connection provide? What risks does this type of connection introduce?
Do local cable companies offer cable modem access? Ask students to research a local cable television service provider on the Internet to see if they provide Internet access. If they do, students should report on what the company requires (for example, must you have a cable modem or will they provide one), what kinds of services they provide, and how much they charge for the services.
Figure 6-17, Figure 6-18
What does DOCSIS stand for? (Answer: Data Over Cable Service Interface Specification)
True/False: Most cable Internet service is asymmetric. (Answer: True)
True/False: A cable modem can plug directly into a coaxial cable wall jack. (Answer: True)
Satellite Internet Service (318)
Discuss who should use satellite Internet service. Communication with satellite Internet service is a good choice for rural areas.
Note that satellite Internet service is subject to delays caused by weather, and is slow upstream with latency delays of 1 or more seconds.
Explain that a geosynchronous satellite is a satellite whose orbital track on the Earth repeats regularly over points on the Earth over time. If such a satellite's orbit lies over the equator, it is called a geostationary satellite. The orbits of the satellites are known as the geosynchronous orbit and geostationary orbit.
Figure 6-19, Figure 6-20, Figure 6-21
Assign a Project: Ask students to research whether satellite Internet service is available in their geographic location.
True/False: Equipment and installation costs for satellite Internet service are higher than other Internet services. (Answer: True)
True/False: Satellite service typically averages 1.0 to 1.5 Mbps downstream speed but only 100 to 256 Kbps upstream. (Answer: True)
True/False: In many urban areas, satellite Internet service is the only alternative to a dial-up connection. (Answer: False)
Fixed Wireless Service (320)
Discuss broadband access.
In areas without pre-existing physical cable or telephone networks, WiMAX may be a viable alternative for broadband access.
Discuss the equipment needed for WiMAX.
Explain that many cable, wireless, and traditional telephone companies are closely examining WiMAX for “last mile” connectivity at high data rates. This could result in lower pricing for both home and business customers as competition lowers prices.
Class Discussion: Point out Figure 6-22, which shows a WiMAX tower, and ask students if they’ve ever seen one. Had they heard of WiMAX before this discussion?
What does WiMAX stand for? (Answer: Worldwide Interoperability for Microwave Access)
True/False: A WiMAX system transmits data to and from WiMAX antennas mounted on towers. (Answer: True)
True/False: Under ideal conditions, WiMAX can transmit data at 700 Mbps. (Answer: False)
Fixed Internet Connection Roundup (321)
Use Figure 6-23 to provide a good overview of almost every type of fixed Internet access. You could use this table throughout the chapter as you discuss the various options.
SECTION C: PORTABLE AND MOBILE INTERNET ACCESS
SECTION C OPENER QUESTION:
062300 What is the difference between portable Internet access and mobile Internet access?
With portable access you cannot work online while moving very far.
Mobile access is less expensive than portable access.
Portable access requires cables, whereas mobile access does not.
Portable access requires a cell phone, whereas mobile access requires a notebook computer.
Internet to Go (322)
Explain that portable Internet access is the ability to easily move your Internet service from one location to another.
Explain that mobile Internet access offers a continuous Internet connection as you are walking or riding in a car.
Class Discussion: Ask students to relay their experiences with portable or mobile Internet access. Do any students own an iPhone or other device with which to access the Internet while on the go?
_______ Internet access can be defined as the ability to easily move your Internet service from one location to another. (Answer: Portable)
_______ Internet access offers a continuous Internet connection as you are walking or riding in a bus, car, train, or plane. (Answer: Mobile)
_______ Internet access includes Wi-Fi, mobile WiMAX, and cellular broadband service. (Answer: Mobile)
Wi-Fi Hotspots (323)
Discuss what a hotspot is.
Discuss the advantages and disadvantages of hotspots.
Discuss free hotspots. Note that hotspots continue to grow; wireless networks that cover entire cities, such as Municipal broadband, have mushroomed. More than 300 metropolitan projects have been started nationwide.
Point out some locations or facilities in your area that provide free Wi-Fi. Have students discuss their use of Wi-Fi.
Assign a Project: Have students visit www.jiwire.com and locate Wi-Fi hotspots in their location.
A(n) _______ is an area in which the public can access a Wi-Fi network that offers Internet service. (Answer: Wi-Fi hotspot)
True/False: Wi-Fi typically provides acceptable mobile Internet access. (Answer: False)
True/False: The speed of a hotspot is related to the speed of the wired line that connects it to the Internet. (Answer: True)
Portable and Mobile WiMAX (324)
Discuss with the students the idea of “Just plug in and jump online anywhere with the service area” as related mobile WiMAX.
Discuss the advantages and disadvantage of mobile WiMax.
Discuss how mobile WiMAX is an up-and-coming standard because it is designed to offer Internet access with seamless handoff from the one tower to another. This would be a good place to discuss how handoff occurs.
Explain that given the limited wired infrastructure in some developing countries, the costs to install a WiMAX station in conjunction with an existing cellular tower or even as a solitary hub are likely to be small in comparison to developing a wired solution.
Explain that areas of low population density and/or flat terrain are particularly suited to WiMAX and its range. For countries that have skipped wired infrastructure as a result of prohibitive costs and unsympathetic geography, WiMAX can enhance wireless infrastructure in an inexpensive, decentralized, deployment-friendly, and effective manner.
True/False: Mobile WiMAX could make it possible for you to deal with a single service provider for all your cell phone and Internet access needs. (Answer: True)
True/False: With WiMAX, you use the same Internet service provider whether you are at home or on the road. (Answer: True)
Portable Satellite Service (325)
Discuss why you might consider using a portable satellite service. Where might it be used? (Campgrounds are a good example).
Discuss the need to readjust the dish to assure it is aimed correctly.
Discuss the price factor. Note that price is a significant consideration.
Figure 6-27, Figure 6-28
Class Discussion: Have students discuss the possible uses of portable satellite service. How does its high price tag limit its usefulness?
Cellular Data Service (326)
Explain that cellular phones, PDAs, and notebook and tablet computers can be configured for mobile Internet access.
Discuss Figure 6-29 with an emphasis on how the generation of the technology impacts the features. See how many different devices the students have. Have the student compare their cellular phones and classify them into a generation.
Discuss WAP and its advantages and disadvantages.
Discuss the kinds of services offered by cellular data services. Page 327 provides an overview of many of them. Ask if students take advantage of any of these services.
Discuss Internet service on a handheld device. If you or a student has one, demonstrate its use.
Discuss how you can use the modem in your phone as a modem for your computer.
Refer students to the New Perspectives Web site for a Student Edition Lab called “Connecting to the Internet.”
What Internet options are available with your students’ cell phone services? Ask students to use the Internet to visit their cellular phone service provider’s Web site and learn about what Internet services they could subscribe to, if they don’t already. How much does the service cost?
_______________ is a communications protocol that provides Internet access from handheld devices, such as cell phones. (Answer: WAP)
___________ is a 3.5G cellular technology with theoretical maximum speeds in excess of 5 Mbps.
SECTION D: INTERNET SERVICES
SECTION D OPENER QUESTION:
062400 On the Internet, application protocols provide consumers with many useful services. Which one of the following correctly describes an Internet-based application protocol?
Chat and Instant messaging use Internet VoIP protocol.
Files can be shared over the Internet using FTP or BitTorrent protocols.
Cloud protocols such as SETI control distributed processing grids.
P2P is used to encrypt personal information to keep it private.
Real-Time Messaging (330)
Ask students what instant messaging systems they use. AOL? Yahoo? Google Talk? Discuss what students see as the differences among the clients. What are the criteria they used for choosing their system?
Remind students that it is possible to save a conversation, in order to refer to it later, which is not possible by telephone. Also note that instant messages typically get logged in a local message history. Note that students should be careful what they put into an instant message because it can be retrieved for later use.
Discuss the security aspects of messaging. Messages can be intercepted so care should be given on the content of the messages.
Figure 6-35, Figure 6-36
Voice over IP (332)
Discuss the drawbacks of using VoIP.
Note that the quality and overall reliability of the phone connection is entirely reliant upon the quality, reliability, and speed of the Internet connection that it is using.
Discuss how shortcomings with Internet connections and Internet service providers (ISPs) can cause a lot of grief with VoIP calls.
Explain that higher overall network latencies can lead to significantly reduced call quality and cause certain problems such as echoing.
Using Figure 6-37, discuss the various ways in which phones are connected to enable use of VoIP.
Note that ATAs are used by many VoIP companies selling VoIP service, where the device is used to replace a user's connection to an existing telephone company.
Explain that when sold in connection with a VoIP service like Vonage, the ATA is usually locked so it cannot be used with another company, and the user can only partly change its configuration.
Discuss the advantages and disadvantages of VoIP. In particular, discuss the concerns of 911 services.
Figure 6-37, Figure 6-38
Ask students if any of them are using or have used VoIP. If so, how did it work? Would they do so again?
Grid Computing (334)
Note that, like the Internet, grid computing evolved from the computational needs of “big science.”
Explain that grid computing can be viewed as an extension or application of the Internet framework to create a more generic resource sharing context.
Discuss some of the projects using grid computing.
Discuss cloud computing and how it differs from grid computing.
Figure 6-39, Figure 6-40, Figure 6-41
Discuss concerns about FTP, especially security concerns.
Explain that passwords and file contents are sent in clear text, which can be intercepted by eavesdroppers. (There are protocol enhancements that circumvent this.)
Note that FTP also uses multiple TCP/IP connections, one for the control connection, and one for each download, upload, or directory listing, and as a result, firewall software needs additional logic to account for these connections.
Note that FTP is a high latency protocol due to the number of commands needed to initiate a transfer.
Explain that FTP offers no integrity check on the receiver side. If transfer is interrupted the receiver has no way to know if the received file is complete or not.
Figure 6-42, Figure 6-43
Demonstrate the use of FTP to transfer files. If the student has FTP available, have them transfer a file.
File Sharing (337)
Explain that file transfer is one of the original applications of the Internet, preceding even e-mail.
Discuss how P2P works.
Note that file sharing first came into the public eye with the popularization of MP3 files in the mid- to late 1990s.
Discuss how BitTorrent works and how P2P is used in its operation.
Discuss copyright implications. File sharing (such as with the Gnutella and Napster networks) grew in popularity with the proliferation of high speed Internet connections, relatively small file size, and high-quality MP3 audio format. Although file sharing technology has legal uses, many users use it to download copyrighted materials without explicit permission: copyright infringement or “piracy.” This has led to attacks against file sharing in general from some copyright owners.
What are the risks of file sharing? Some file sharing software comes bundled with malware such as spyware or adware. Sometimes this malware remains installed on the system even if the original file sharing software is removed, and can be very difficult to eliminate. In many cases, such malware can interfere with the correct operation of Web browsers, anti-virus software, anti-spyware, and software firewalls, and can cause degraded performance on affected systems. Such malware is typically bundled with proprietary software, and not those in open source.
Class Discussion: Survey students about their use of P2P file sharing. Have students ever used Napster, Gnutella, or BitTorrent? What kinds of files have they exchanged using these resources?
A(n) __________ computing system is a network of diverse computers in which each computer contributes processing resources to solving a single problem. (Answer: grid )
________ is a file sharing protocol that distributes the role of file server across a collection of dispersed computers.
SECTION E: INTERNET SECURITY
SECTION E OPENER QUESTION:
062500 Securing your computer from Internet-based intrusions is an important aspect of computer security. Which one of the following is NOT a useful security technique?
Setting up NAT on a router
Activating firewall software
Checking the status of software ports
Activating your computer’s file sharing options
Intrusion Attempts (340)
Explain what an intrusion is.
Explain that to port scan a host is to scan for multiple listening ports on a single target host.
Figure 6-46, Figure 6-47
Securing Ports (342)
Classify firewalls. One classification of firewalls is as personal or network.
Discuss personal firewalls, a software application that normally filters traffic entering or leaving a single computer.
Discuss network firewalls, normally running on a dedicated network device or computer positioned on the boundary of two or more networks or DMZs (demilitarized zones). Such a firewall filters all traffic entering or leaving the connected networks.
Discuss closing ports that are not in use.
Discuss turning off computers when not in use if an “always-on” connection is being used.
Explain the firewall protection used by your school’s network.
The New Perspectives Lab “Securing Your Connection” deals with issues that relate to this section of the textbook. You might want to go through the lab during class time if you have a computer with a projection device. Or, assign this lab for students to do on their own.
Figure 6-48, Figure 6-49, Figure 6-50
Routers and NAT (343)
Discuss how routers and NATs work. One easy illustration for the different functions of routers and switches is to think of switches as neighborhood streets, and the router as intersections with street signs.
Discuss IP addressing schemes and how private IP addresses work.
Discuss network address translation and how it is used to transfer your packets.
Figure 6-51, Figure 6-52
Virtual Private Networks (345)
Note that VPN is a secure way for different corporations to provide user access to the corporate network and for remote networks to communicate with each other across the Internet.
Point out that VPNs are frequently used by people who work from home or are frequently on the road.
Refer students to the New Perspectives Web site for a Student Edition Lab called “Protecting Your Privacy Online.”
WHAT DO YOU THINK ?
063100 Should governments be allowed to block access to Web sites based on local religions, politics, and customs?
c. Not sure
063200 Do you believe that a privately held Internet service provider like AOL has the right to censor the data posted on Web sites it hosts?
c. Not sure
063300 Should companies like Microsoft, Yahoo!, and Cisco Systems provide blocking technology to foreign governments?
c. Not sure
063400 Would you use filtering software that was preprogrammed to block pornographic and nuisance Web sites?