Network+ Guide to Networks, 4 th Edition

Chapter 13 Solutions

Review Questions


1. Which of the following percentages represents the highest availability?

a. 99.99%


2. Which of the following is most likely to spread itself by acting as an e-mail attachment?

b. worm


3. What characteristic of the IRC protocol makes it an effective way to spread viruses and worms quickly?

b. It broadcasts communication from one chat room participant to others.


4. Which of the following techniques does a polymorphic virus employ to make itself more difficult to detect?

a. It frequently changes its code characteristics.


5. You have detected the presence of a boot sector virus on your workstation. What is the first step you take to disinfect your machine?

c. Boot the workstation from an uninfected, write-protected disk.


6. If your antivirus software uses signature scanning, what must you do to keep its virus-fighting capabilities current?

d. Regularly update the antivirus software's signature database.


7. You receive a message that is a known virus hoax. What should you do about it?

a. Ignore and delete the message.


8. Over time, what can electrical line noise do to your system?

b. damage circuitry on the system board


9. Approximately how long will an online UPS take to switch its attached devices to battery power?

d. no time


10. When purchasing a UPS, you have to match the power needs of your system according to what unit of measure?

c. volt-amps


11. Which of the following is the most highly fault-tolerant network topology?

c. mesh


12. What makes SONET a highly fault-tolerant technology?

a. It uses dual, fiber-optic rings to connect nodes.


13. Why is simple disk striping not fault-tolerant?

b. If one disk fails, data contained on that disk is unavailable.


14. What RAID level uses disk mirroring?

b. 1


15. The most common form of RAID used on modern networks relies on what techniques?

c. disk striping with distributed parity


16. Which of the following can be considered an advantage of clustering servers over mirroring servers?

d. Clustering fail-over takes place more rapidly.


17. Why do storage area networks save and retrieve files faster than network area storage devices?

d. They use a proprietary network transmission method, rather than Ethernet or

Token Ring.


18. Suppose you are the network manager for an ISP whose network contains five file servers that use software RAID, a NAS installation, and a SAN. You learn that the company is taking on a hugeWeb hosting client and you need to add 1 TB of storage space as soon as possible. To what part of the network should you add the storage so that it causes the least disruption to the existing network?

d. to the SAN


19. Which factor must you consider when using online backups that you don't typically have to consider when backing up to a LAN tape drive?

c. security


20. In a grandfather-father-son backup scheme, the October—week 1—Thursday backup tape would contain what type of files?

c. files changed since Wednesday (a day before)


21. In the grandfather-father-son backup scheme, how frequently is a full backup performed? (Choose all that apply.)

b. weekly

e. monthly


22. Which of the following is a major disadvantage to performing full system backups on a daily basis?

a. They would take too long to perform.


23. What is the difference between an incremental backup and a differential backup?

b. An incremental backup resets the archive bit after backing up files, whereas a differential backup does not.


24. What fault-tolerance technique is included in Windows Server 2003 and NetWare 6.5 to make sure that Active Directory and eDirectory are always available?

c. replication


25. You have been charged with creating a disaster recovery contingency plan for the federal benefits agency where you work. Your supervisor has said that the network must have the highest availability possible, no matter what the cost. Which type of disaster recovery site do you recommend?

d. hot site


Hands-On Projects


Project 13-1

In this project, students experiment with installing and using an anti-virus software application. This project is written to work with Windows XP workstations. An Internet connection and a modern browser are necessary to obtain the anti-virus software.

Steps 1 – 7: Students download and install the AVG Anti-Virus software from Grisoft, which is available as a trial for no charge at: .

Steps 8 – 10: Students run the AVG Anti-Virus software and scan their workstations' hard disks for viruses.


Project 13-2

Students continue working with the anti-virus software in this project.

Steps 1 – 5: Students download the latest virus signature update to make sure their version of AVG Anti-Virus is current.

Steps 6 – 9: Students run the AVG Anti-Virus program, verifying that the update took place and re-scanning their hard disks for viruses.


Project 13-3

In this project, students use an online UPS capacity tool to determine the UPS needed for an imaginary network server. This project requires workstations with access to the Internet and a modern browser; however, the workstations do not necessarily need to be Windows XP systems.

Note: At the time of this writing, steps for sizing a UPS at the APC Web site ( were correct. This site has proven relatively stable over the last several years. However, due to site updates and changes, steps might differ slightly.


Case Projects


Case Project 13-1

Critical points of failure on this network include switches and hubs to the surgery rooms, the T3 link to the ISP, the serial interface on the CSU/DSU for the T3 link, each server that contains patient records or other critical data, and the NICs, hard disks, cabling, memory and CPU in those servers. Less critical would be the administrative and classroom machines. All possible redundancy should be employed to protect the availability of the operating room systems, including redundant cabling, redundant NICs in the server that those workstations use, fail-over capabilities in the switches or hubs these machines attach to, UPS backup for the servers that contain patient records, and centralized data backup for all servers. With five servers, it might also be desirable to use a server clustering solution. In addition, the link to the ISP should have a backup mechanism, either an ISDN or DSL line or an arrangement with the ISP to have a second dedicated line (for example, a fractional T1) available for emergencies.


Case Project 13-2

To cut costs, the IT director must be questioned about the priorities for the system are. Together, the consultant and the director can examine each potential point of failure and ask, “What's the worst that could happen if this piece of the system failed?” Going through this exercise will help prioritize the availability measures suggested in Case Project 13-1. It might be sufficient to have redundant NICs and RAID drives in the servers, rather than implementing a clustered solution. It might be sufficient to leave some physicians' offices on hubs or switches that do not have fail-over capability, assuming that they could walk to another part of the building and use someone else's computer in a pinch. It might be sufficient to use an ISDN or DSL line to provide WAN redundancy, rather than a second T1. However, the servers and their links to the operating rooms must have redundancy.


Case Project 13-3

The disaster recovery outline should address the disaster recovery team with an emergency coordinator, where offsite backups will be stored and how data will be recovered, how communications between disaster recovery team members and other hospital staff will take place after a disaster, which vendors will provide new software and hardware, and which elements of the network should be reestablished first. If a cold, warm, or hot site is prepared, the disaster recovery plan should indicate procedures for making that site go live (that is, take the place of the downed network).