Instructor S Manual Materials to Accompany s2

Instructor’s Manual Materials to Accompany COMPUTERS ARE YOUR FUTURE

CHAPTER 8 NETWORKS: COMMUNICATING AND SHARING RESOURCES

CHAPTER ANSWERS TO END-OF-CHAPTER QUESTIONS

Matching

1. network operating system (NOS) n

2. network architecture k

3. protocols j

4. Ethernet i

5. Internet protocol b

6. peer-to-peer network d

7. routers f

8. clients a

9. token e

10. packets h

11. latency g

12. bus topology l

13. network topology m

14. collision o

15. node c

Multiple Choice

1. Which of the following is not a computer network?

a. local area network (LAN)

b. leased-line area network (L2AN)

c. wide area network (WAN)

d. peer-to-peer network (P2PN) b

a. circuit switching

b. packet switching

c. both a and b

d. none of the above c

3. Which term describes a computer that is connected to a network?

a. unit

b. mode

c. workstation

d. terminal unit c

4. To connect to a LAN, a computer must be equipped with which of the following?

a. network interface card (NIC)

b. backbone

c. both a and b

d. none of the above a

5. Which type of network topology is centered on a hub?

a. star

b. ring

c. bus

d. LAN a

6. Which of the following is not a LAN topology?

b. star

c. hub

d. bus c

7. Which term describes the phenomenon of more than one computer trying to use the network at the same time?

a. contention

b. competition

c. communication

d. congestion a

8. Which of the following is a WAN network connection point that enables users to access the WAN through a local phone call?

a. point of presence (POP)

b. leased line

c. permanent virtual circuit (PVC)

d. frame relay a

9. Which of the following is the most popular LAN standard?

a. ISDN

b. LocalTalk

c. Ethernet

d. Synchronous Optical Network (SONET) c

10. Which of the following is the oldest and most widely used packet-switching protocol for WAN usage?

a. 10BaseT

c. X.25

d. T1 a

Fill in the Blank 1. A(n) ______links two or more computers together to enable data and resource exchange. network

2. A(n) ______uses direct cables, radio waves, or infrared signals to link computers within a small geographic area.

LAN or local area network

3. When a PC is connected to a LAN, the PC is called a(n) ______. node

4. A(n) ______is a PC expansion board needed to connect a computer to a LAN.

NIC or network interchange card

5. With ______, an outgoing message is divided into data units of a fixed size called packets. packet switching

6. ______is a set of standards that offers Ethernet speed without wires.

7. ______install, maintain, and support computer networks, interact with users, handle security, and troubleshoot problems.

Network administrators

8. In a(n) ______, the network cable forms a single bus to which every workstation is attached. bus topology

9. A network uses ______(standards) that enable network-connected devices to communicate with each other. protocols

Copyright © 2006 Prentice-Hall. All rights reserved. 5 Chapter 8: Networks: Communicating and Sharing Resources 10. The high-capacity transmission lines that carry WAN traffic are called ______. backbones

11. ______defines how one Internet-connected computer can contact another to exchange control and confirmation messages.

TCP or Transmission Control Protocol

12. With a(n) ______, file sharing allows users to decide which computer files, if any, are accessible to other users on the network.

P2PN or peer-to-peer network

13. ______is the networking system built into every Macintosh computer.

LocalTalk

14. A(n) ______uses long-distance transmission media to link computers separated by a few miles or even thousands of miles.

WAN or wide area network

15. With ______, the network creates a physical end-to-end circuit between the sending and receiving computers. circuit switching

Short Answer

1. Describe a protocol stack and then draw a diagram that shows what you have described.

In a computer network, a protocol stack is a means of conceptualizing network architecture in which the various layers of network functionality are viewed as a vertical stack, like the layers of a layer cake, in computers linked to the network. When one computer sends a message to the network, the message goes down the stack and then traverses the network; on the receiving computer, the message goes up the stack.

2. Explain the difference between peer-to-peer and client/server networks.

In a peer-to-peer network, all the computers on the network are equals, and there is no file server. Each computer user decides which, if any, files will be accessible to other users on the network. Although peer-to- peer networks are easy to set up, they tend to slow down with heavy use, and keeping track of all the shared files and peripherals quickly becomes confusing. For this reason, peer-to-peer LANs are not suitable for networks that connect more than one or two dozen computers.

A client/server network consists of one or more file servers, as well as networked workstations. The clients, which are all the computers that can access the server, send requests to the server. The client/server model works with any size or physical layout of LAN and does not tend to slow down with heavy use.

3. How do LANs and WANs differ?

Distance and media are the deciding factors in differentiating these networks from each other. LANS use direct cabling or localized wireless radio or infrared signals to link computers in a small geographic area. WANs use long-distance transmission media, such as phone lines, microwave transmissions, or even satellites.

4. Name three types of LAN topologies, and describe how each works.

A bus is a network configuration in which the network cable is a single bus or backbone to which each workstation is connected. The two ends of the bus have special connectors called terminators.

A star is a network where all other devices are connected to a central device, typically a computer. This configuration easily allows new users to be added to the network.

A ring is a network design where all devices are connected in a closed loop or ring. In this network, data only travels in one direction around the ring.

5. What is the difference between contention and congestion?

In a computer network, contention is a problem that arises when two or more computers try to access the network at the same time. Contention can result in collisions, which can destroy data. Congestion occurs in a packet-switching network and is a performance interruption that occurs when a segment of the network experiences an overload.

Copyright © 2006 Prentice-Hall. All rights reserved. 7 Chapter 8: Networks: Communicating and Sharing Resources 6. How do circuit switching and packet switching differ? What are the advantages of each method?

Circuit-switching networks create physical end-to-end circuits between the sending and receiving computers. This is similar to a telephone connection between two individuals. Once a connection is made, this method allows for rapid communication between the two computers.

A packet-switching network breaks down outgoing messages into distinct data units of a fixed size—packets —and transports the packets over various routes from the sending computer to the receiving computer. When all the packets arrive at the receiving computer, they are rearranged into their original order. Although this is a slower transmission process, there is no need to wait for a dedicated connection between the two computers.