Business Data Communications and Networking 7th Edition Test Bank - Chapter 09

Business Data Communications and Networking 7th Edition Test Bank - Chapter 09 (400 Level Course)

TRUE/FALSE

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. The Internet is flat in structure. [False, it is hierarchical in structure; p. 268]
Easy

2. National Internet service providers connect together and exchange data at Network Access Points. [True; p. 268]
Easy

3. As the number of ISPs has grown, a new form of network access point called a metropolitan area exchange has emerged. [True; p. 269]
Moderate

4. Peering means that a national ISP does not charge another national ISP to transmit its messages. [True, p. 270]
Easy

5. A point-of-presence is the place at which the ISP provides services to its customers. [True; p. 270]
Easy

6. Technologies such as DSL and cable modem are called narrowband technologies. [False, they are broadband technologies; p. 273-274]
Easy

7. Digital Subscriber Line is a family of multipoint technologies. [False, DSL is a family of point-to-point technologies; p. 274]
Moderate

8. To use DSL, a customer needs a DSL Access Multiplexer installed at his or her location. [False, a customer needs customer premises equipment to use DSL; p. 274]
Moderate

9. Another term for a DSL modem is a DSL brouter. [False, it is known as a DSL router; p. 274]
Moderate

10. The least common type of DSL in use today is Asymmetric DSL. [False, it is the most common; p. 275]

11. ASL is called asymmetric because its two data channels have exactly the same speed. [False, they have different speeds; p. 275]
Easy

12. Very-high-data-rate Digital Subscriber Line is designed for use over long local loops. [False, it is designed to be used over very short local loops; p. 276]
Easy

13. The dominant standard for a cable modem is Data over Cable System Interface Specification. [True; p. 276]
Easy

14. A distribution hub is also known as a headend. [True; p. 278]
Moderate

15. Wireless DSL is a line-of-sight technology. [True; p. 278]
Easy

16. Wireless Application Environment supports mobile wireless Internet applications on devices with small display screens operating over low speed wireless connections. [True; p. 280]
Easy

17. Fiber-to-the-home is another term for satellite fixed wireless technology. [False, it is the term for running optical fiber into the home; p. 281]
Easy

18. The Internet Engineering Steering Group provides strategic architectural oversight for the Internet. [False, this group is responsible for technical management of IETF activities and the Internet standards process; p. 282]
Moderate

19. Internet 2 is the common name for the Abilene network. [True; p. 284]
Easy

20. Each of the networks in Internet 2 has a set of access points called terapops. [False, they are called gigapops; p. 285-286]
Moderate

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, moderate, difficult) and page number(s) relevant to the topic are also furnished.

1. At the top of the Internet structure are national ___________, such as BBN Planet.
a. Network Access Points
b. Internet service providers
c. bridges
d. LATAs
e. digital subscriber lines
Answer: b, Easy, p. 268

2. National ISPs connect together and exchange data at ___________.
a. Network Access Points
b. cable modem termination system endpoints
c. distribution hubs
d. the Internet engineering task force headquarters
e. the Internet Society network center
Answer: a, Easy, p. 268

3. _________ are smaller versions of NAPs that link a set of regional ISPs.
a. mini Network Access Points
b. cable modem termination system endpoints
c. distribution hubs
d. metropolitan area exchanges
e. points-of-presence
Answer: d, Easy, p. 269

4. __________ has led to the belief that the Internet is “free”.
a. Encrypting
b. Peering
c. Bridging
d. Tolling
e. Polling
Answer: b, Moderate, p. 269

5. ___________ refers to the fact that ISPs do not charge one another (at the same level) for transferring messages they exchange across an NAP or MAE.
a. Popping
b. Peering
c. Yiping
d. Napping
e. Chargebacking
Answer: b, Easy, p. 269

6. A _________ is the place at which the ISP provides services to its customers.
a. remote access point
b. network access point
c. cable modem termination system endpoint
d. point-of-presence
e. metropolitan area exchange
Answer: d, Moderate, p. 270

7. In general, local ISPs make money by charging ________.
a. customers
b. ICANN
c. UCAID
d. the DSLAM
e. CSUs/DSUs
Answer: a, Easy, p. 270

8. Which of the following is not an ISP in either the United States or Canada?
a. CAIS
b. iSTAR
c. CompuServe
d. Sprint
e. ISOC
Answer: e, Moderate, p. 272

9. Technologies that provide higher-speed communications than traditional modems (e.g., DSL) are known as ______________ technologies.
a. middleband
b. narrowband
c. rubberband
d. metalband
e. broadband
Answer: e, Easy, p. 273-274

10. Digital _________ Line is a family of point-to-point technologies designed to provide high-speed data transmission over traditional telephone lines.
a. System
b. Satisfaction
c. Speedy
d. Subscriber
e. Switch
Answer: d, Easy, p. 274

11. For access to DSL, __________ equipment is installed at the customer location.
a. point-of-presence
b. satellite dish
c. customer premises
d. metropolitan area exchange
e. network access point
Answer: c, Easy, p. 274

12. A __________ separates traditional voice telephone transmission from the data transmissions in the equipment located at the customer site for DSL.
a. line splitter
b. V.32bis modem
c. line analyzer
d. main distribution frame
e. network access point
Answer: a, Easy, p. 274

13. The _________ is the connection from a home or business to the telephone company end office.
a. distribution hub
b. RFC
c. UCAID
d. local loop
e. CA*net 3
Answer: d, Easy, p. 274

14. A DSL modem is also known as a:
a. DSL bridge
b. DSL brouter
c. DSL router
d. DSL gateway
e. DSL hub
Answer: c, Easy, p. 274

15. At the DSL local carrier’s office, the __________ demultiplexes the data streams and converts them into ATM data.
a. DSLAM
b. GrandSlam
c. WAP
d. line splitter
e. X.25 PAD
Answer: a, Moderate, p. 274

16. Asymmetric DSL uses ___________ multiplexing to create three separate channels over one local loop circuit.
a. inverse
b. time division
c. statistical time division
d. wave division
e. frequency division
Answer: e, Moderate, p. 275

17. Very-high-data-rate DSL uses multiplexing to provide _________ channels.
a. two
b. three
c. four
d. five
e. six
Answer: b, Moderate, p. 276

18. Which of the following statements is true?
a. On a circuit, the shorter the distance, the higher the speed.
b. On a circuit, the longer the distance, the higher the speed.
c. On a circuit, the longer the distance, less attenuation occurs.
d. On a circuit, the shorter the distance, more attenuation occurs.
e. When more attenuation occurs, higher frequency signals can be used effectively.
Answer: a, Moderate, p. 276

19. A digital service offered by cable companies is the _________.
a. Abilene network
b. WAP proxy
c. G.Lite ADSL
d. cable modem
e. Next Generation Internet
Answer: d, Easy, p. 276

20. Another term for cable networks that use both fiber-optic and coaxial cable is __________.
a. fixed wireless
b. mobile wireless
c. distribution hub
d. hybrid fiber coax
e. fibrax
Answer: d, Easy, p. 276

21. To balance the trade-off between speed and distance in ADSL, most ADSL service providers have chosen a T1 level of ADSL, and offer it under the trademarked name of _________ ADSL.
a. CA*net 3
b. DOCSIS
c. G.Lite
d. OE
e. UCAID
Answer: c, Moderate, p. 276

22. A T1 level of ADSL has a maximum downstream rate of about _________ Mbps.
a. 9000
b. 8.4
c. 1.5
d. 650
e. 6.1
Answer: c, Difficult, p. 276

23. A headend is also referred to as a:
a. Abilene network
b. WAP proxy
c. cable modem
d. distribution hub
e. fiber node
Answer: d, Moderate, p. 278

24. Wireless DSL requires __________ to be effective.
a. Abilene networks
b. tall buildings or towers
c. cable modems
d. fiber nodes
e. hybrid fiber coax
Answer: b, Easy, p. 278

25. A(n) __________ is used to connect a fiber optic cable from the cable TV company side to a coaxial cable on the customer side.
a. CA*net 3
b. RFC
c. WAP proxy
d. fixed wireless connection
e. optical-electrical converter
Answer: e, Easy, p. 278

26. A(n) ___________ contains a series of cable modems/multiplexers and converts the data from cable modem protocols into protocols needed for Internet traffic, before passing them to a router connected to an ISP POP.
a. Internet steering system
b. optical-electrical converter
c. WAP proxy
d. cable modem termination system
e. fixed wireless system
Answer: d, Easy, p. 278

27. The multipoint version of fixed wireless is sometimes known as:
a. point-to-multipoint
b. point-to-point
c. CA*Net3
d. DOCSIS
e. DSLAM
Answer: a, Moderate, p. 279

28. ___________ is designed to enable the use of normal Web applications on computers and devices with small display screen operating over low speed wireless connections.
a. CA*Net3
b. The Abilene network
c. Internet 2
d. Wireless Application Protocol
e. X.25 protocol
Answer: d, Easy, p. 280

29. A transceiver at the WAP gateway passes requests to a __________ server from a handheld device.
a. main distribution
b. Internet Society
c. local loop
d. wireless telephony application
e. line splitter
Answer: d, Moderate, p. 280

30. A ____________ translates a wireless application request to HTTP and sends it over the Internet to the desired Web server.
a. passive optical scanner
b. local loop
c. cable modem
d. peer
e. WAP proxy
Answer: e, Moderate, p. 280

31. Running fiber optic cable into the home as an alternative networking technology to DSL is called:
a. passive optical networking
b. active optical networking
c. passive fibrous networking
d. active fibrous networking
e. wireless networking
Answer: a, Easy, p. 281

32. In passive optical networking, the optical signal has a maximum length of about __________.
a. 500 meters
b. 1000 meters
c. 1 mile
d. 5 miles
e. 10 miles
Answer: e, Moderate, p. 281

33. _________ is being pioneered by Yipes.com.
a. Active fibrous networking
b. The Abilene network
c. CA*Net3
d. Ethernet to the home
e. Next Generation Internet
Answer: d, Moderate, p. 281-282

34. The closest the Internet has to an “owning” organization is the ___________.
a. Internet Service Provider
b. Abilene network
c. CA*Net3
d. University Corporation for Advanced Internet Development
e. Internet Society
Answer: e, Easy, p. 282

35. Which of the following is not part of the work of the Internet Society?
a. public policy
b. connecting optical-electrical converters
c. education
d. development of Internet standards
e. maintenance of Internet standards
Answer: b, Easy, p. 282
36. The ________ is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and smooth operation of the Internet.
a. Internet Society
b. Internet Engineering Task Force
c. Internet Engineering Steering Committee
d. Internet Architecture Board
e. Internet Research Task Force
Answer: b, Moderate, p. 282

37. The ___________ is responsible for technical management of IETF and the Internet standards process.
a. Internet Society
b. University Corporation for Advanced Internet Development
c. Internet Engineering Steering Committee
d. Internet Architecture Board
e. Internet Research Task Force
Answer: c, Moderate, p. 282

38. The __________ provides strategic architectural oversight to the Internet.
a. Internet Society
b. Internet Engineering Task Force
c. Internet Engineering Steering Committee
d. Internet Architecture Board
e. Internet Research Task Force
Answer: d, Easy, p. 283

39. The _________operates like the IETF through small research groups focused on specific issues.
a. Internet Society
b. University Corporation for Advanced Internet Development
c. Internet Engineering Steering Committee
d. Internet Architecture Board
e. Internet Research Task Force
Answer: e, Easy, p. 283

40. In 1996, The National Science foundation provided $100 Million to start the ___________ program to develop the very-high-performance Backbone Network Service.
a. CA*Net3
b. UCAID
c. Next Generation Internet
d. Internet 2
e. WAP proxy
Answer: c, Moderate, p. 284

41. Internet 2 is also known as:
a. CA*Net3
b. IETF
c. Next Generation Internet
d. the Abilene network
e. passive optical networking
Answer: d, Moderate, p. 284

42. CA*Net3 was developed by a Canadian organization known as:
a. IETF
b. ARDNOC
c. ADSL
d. RFC
e. UCAID
Answer: b, Moderate, p. 284

43. Which of the following new Internet efforts was started by 34 universities?
a. CA*net 3
b. ARDNOC
c. vBNS
d. NGI
e. UCAID
Answer: e, Moderate, p. 284

44. vBNS was developed by one organization, but is currently being run by another organization, _____________.
a. AT&T
b. Sprint
c. Yipes
d. MCI WorldCom
e. the Abilene network
Answer: d, Moderate, p. 284

45. Which of the following groups developed the Canadian next generation Internet?
a. MCI WorldCom
b. ARDNOC
c. UCAID
d. Yipes
e. NSF
Answer: b, Moderate, p. 284

46. Which of the following groups developed Internet 2?
a. MCI WorldCom
b. ARDNOC
c. UCAID
d. Yipes
e. ISOC
Answer: c, Moderate, p. 284

47. Which high-speed network is funded by the U.S. Department of Defense?
a. HSCC
b. Microsoft network
c. Abilene
d. CA*net 3
e. Internet 2
Answer: a, Difficult, p. 285

48. A high-speed Internet has a set of access points called ____pops that provide point-of-presence at ________ speeds.
a. giga, gigabit
b. mega, megabit
c. multi, multibit
d. giga, megabit
e. multi, gigabit
Answer: a, Easy, p. 285-286

49. ____________ is a new application for a high-speed Internet.
a. ARDNOC
b. Tele-immersion
c. UCAID
d. Yipes.com
e. G.Lite ADSL
Answer: b, Easy, p. 286

50. Most of the next generation Internet networks currently use ________ as the primary network layer protocol.
a. IPv4
b. TCP
c. IPv6
d. X.25
e. SNA
Answer: c, Easy, p. 286

Short Answer Questions

1. What is a POP?

Answer: A POP is a point-of-presence. It is the place that the ISP provides services to its customers. In order to connect into the Internet, a customer must establish a circuit from his or her location into the ISP POP. Each ISP has one or more POPs.

2. What type of circuits is commonly used to build the Internet today? What type of circuits is commonly used to build Internet 2?

Answer: As of mid-2001, the backbone circuits of the major national ISPs operate at ATM OC-12 (622 Mbps). Most of the national ISPs plan to convert their principal backbones to OC-192 (10 Gbps) by the end of 2001.

Internet 2 circuits are mainly SONET and ATM OC-48 running at 2.4 Gbps, with a few SONET or ATM OC-12 (622 Mbps).

3. How does a DSL modem differ from a DSLAM?

Answer: The DSL modem is both a modem and an FDM multiplexer. This produces Ethernet 10BaseT packets to serve the needs of a small network. The DSL modem is part of the customer premises equipment for DSL.

A DSLAM is equipment at the main distribution frame at the local carrier’s end office. The DSLAM demultiplexes the data streams and converts them into ATM data that are then distributed to the ISPs.

4. How does VDSL work?

Answer: VDSL is asymmetric DSL service designed for user over very short local loops of at most 4,500 feet, although 1,000 feet is more typical. It uses frequency division multiplexing to provide three channels: the normal analog voice channel, an upstream digital channel, and a downstream digital channel.

5. Explain how cable modems work.

Answer: Cable modem architecture is very similar to DSL. However, while DSL is a point-to-point technology, cable modems use shared multipoint circuits. With cable modems, each user must compete with other users for the available capacity. Furthermore, since the cable circuit is a multipoint circuit, all messages on the circuit go to all computers on the circuit.

6. How is the IETF related to the IRTF?

Answer: The IRTF operates much like the IETF, through small research groups focused on specific issues. While IETF working groups focus on current issues, IRTF research groups work on long term issues related to Internet protocols, applications, architectures, and technology.

7. How does wireless DSL work?

Answer: Fixed wireless requires a ling of sight between the communicating transmitters. For this reason, it has limited application, because it requires tall buildings or towers to be effective.

Fixed wireless comes in both point-to-point and multipoint versions. The point-to-point version is designed to connect only two locations and is often used as backbone between buildings owned by the same organization. The multipoint version is sometimes called point-to-multipoint because there is one central receiver and all other locations communicate only with it. The multipoint version is designed as an alternative to DSL and cable modems and is intended for use by an ISP supporting a small number of customers. Like cable modems, the circuit is a shared circuit, so uses must compete for the shared capacity, but most installations are limited to a few dozen users. Data transmission for both versions ranges from 1.5 Mbps to 11 Mbps depending on the vendor.

8. How does ADSL work?

Answer: Asymmetric DSL uses frequency division multiplexing to create three separate channels over one local loop circuit. One channel is the traditional voice telephone circuit. A second channel is a relatively high speed simplex data channel downstream from the carrier’s end office to the customer. The third channel is a slightly slower duplex data channel primarily used for upstream from the customer to the carrier’s end office. ASL is called asymmetric because its two data channels have different speed. Each of the two data channels are further multiplexed using time division multiplexing so that they can be further subdivided.

The size of the two digital channels depends upon the distance from the CPE to the end office. The shorter the distance, the higher the speed, because with a shorter distance, the circuit suffers less attenuation and higher frequency signals can be used providing a greater bandwidth for modulation.

9. Explain how Yipes.com works.

Answer: Yipes.com is pioneering Ethernet to the home. The common carrier installs a TCP/IP router with 10BaseT or 100BasedT connections into the customer’s network and an Ethernet fiber on the other. The IP/Ethernet traffic moves from the router into the carrier’s Ethernet MAN and then onto the Internet. Conversions between protocols are not required at the customer site so connecting to the network is much simpler with this Internet access technology.

10. What is a PON and how does it work?

Answer: Passive Optical Networking is: running fiber optic cable into the home. Data is transmitted from the telephone company switch office down the fiber cable using wave division multiplexing, providing hundreds or thousands of channels. At each subscriber location, a fiber splitter separates the channels belonging to that location and runs them into an optical electrical converter that then connects to a 10BaseT hub.

This approach is called passive optical because the splitters require no electrical current and thus are quicker and easier to install than traditional electrical-based hubs and repeaters. However, since they are passive, the optical signal fails quickly, so there is a maximum length of about 10 miles.

Each single fiber has a capacity of about 155 Mbps, which must be allocated among subscribers.

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