Name: 
 

Data  Comm Rev. 3



True/False
Indicate whether the statement is true or false.
 

 1. 

Wide area networks share a few characteristics with local area networks.
 

 2. 

Many of the same technologies and communications protocols found in local area networks are used to create metropolitan area networks.
 

 3. 

LANs cover much greater distances than MANs do.
 

 4. 

SONET was designed to support multiple streams of voice channels.
 

 5. 

A wide area network’s sub-network, or cloud, may be categorized by the way it transfers information from one end of the sub-network to the other.
 

 6. 

A virtual circuit breaks a large amount of data into n packets.
 

 7. 

Broadcast networks are as common as circuit-switched and packet-switched networks.
 

 8. 

A wide area network’s underlying sub-network consists of multiple nodes, each with multiple possible connections to other nodes within the sub-network.
 

 9. 

You can assign many meanings to the weights in a weighted network graph.
 

 10. 

Most wide area networks use some form of Dijkstra’s algorithm to determine a least-cost route through a network.
 

 11. 

When all the routing information is in one place, it is difficult to make updates to the routing information.
 

 12. 

CSMA/CA is the most popular LAN protocol.
 

 13. 

Current estimates suggest that there are more than 450 million hosts (computer sites that store and deliver Web pages) connected to the Internet.
 

 14. 

Currently, almost all networks involved in the Internet use IP version 6.
 

 15. 

The UDP header contains only four fields—Source Port, Destination Port, Length, and Checksum.
 

 16. 

Every device that has a connection to the Internet is assigned an IP address.
 

 17. 

Home and small business local area networks often use NAT to conserve IP addresses.
 

 18. 

The Internet recognizes URLs directly.
 

 19. 

To make IP addresses a little easier for human beings to understand, the 32-bit binary addresses are represented by dotted decimal notation.
 

 20. 

Only two wires are required to complete a telephone circuit.
 

 21. 

Quarter-T-1 and half-T-1 lines are called fractional T-1 services.
 

 22. 

The price of the PVC is inversely proportional to the CIR level.
 

 23. 

ATM transfer rates are as fast as 311 Mbps.
 

 24. 

A worm is a form of computer virus.
 

 25. 

Many employees feel surveillance is an intrusion into their privacy.
 

 26. 

Rarely, passwords become known, or “misplaced,” and fall into the wrong hands.
 

 27. 

Early cryptography algorithms used the same key for both encryption and decryption.
 

 28. 

One popular application of IPsec is in the support of virtual private networks.
 

 29. 

To authenticate electronic documents as yours, you need to create a digital signature.
 

 30. 

A firewall cannot limit users on the Internet from accessing certain portions of a corporate network.
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

____ area networks can cover large geographic distances, including the entire Earth.
a.
Personal
c.
Wide
b.
Local
d.
Universal
 

 2. 

A local area network works as a ____ network in that clusters of workstations are connected to a central point (hub or switch) through which workstations can transmit messages to one another.
a.
star-based
c.
ring-based
b.
bus-based
d.
star-ring-based
 

 3. 

All wide area networks are collections of at least two basic types of equipment: a station and a ____.
a.
link
c.
workstation
b.
server
d.
node
 

 4. 

____ and virtual circuit networks require path setup time and cannot dynamically reroute packets should a network problem occur.
a.
Broadcast
c.
Circuit-switched
b.
Wireless
d.
Datagram
 

 5. 

A ____ network is the only network that offers a dedicated path.
a.
packet-switched
c.
virtual circuit
b.
broadcast
d.
circuit-switched
 

 6. 

____ applications do not negotiate a connection, and the transfer of data is rarely, if ever, acknowledged.
a.
FTP
c.
Connection-oriented
b.
Connectionless
d.
Reliable service
 

 7. 

A network limit, called the ____, can be placed on how many times any packet is copied.
a.
hop limit
c.
time to live
b.
hop count
d.
time to hop
 

 8. 

Each time a packet is copied, a counter associated with the packet increases by one. This counter is called the ____.
a.
hop limit
c.
TTL count
b.
time to live
d.
hop count
 

 9. 

____ is advantageous when a copy of a packet needs to get to all nodes.
a.
Flooding
c.
Dijkstra’s shortest-path
b.
Dijkstra’s least-cost
d.
Dijkstra’s maximum-cost
 

 10. 

With ____ routing, routing tables are created once, typically when the network is installed, and then never updated again.
a.
fixed
c.
changing
b.
adaptive
d.
modifying
 

 11. 

When a network or a part of a network becomes so saturated with data packets that packet transfer is noticeably impeded, ____ occurs.
a.
network flowing
c.
frame control
b.
packet control
d.
network congestion
 

 12. 

A ____ is a legally binding, written document, that can include service parameters offered in the service, various types of service/support options, incentives if the service levels are exceeded, and penalties if service levels are not met.
a.
connection admission control
c.
software license agreement
b.
service level agreement
d.
congestion control
 

 13. 

During the late 1960s, a branch of the U.S. government titled the ____ created one of the country’s first wide area packet-switched networks.
a.
Department of Defense
b.
IEEE
c.
Advanced Research Projects Agency (ARPA)
d.
IETF
 

 14. 

____ are used to select unique documents from anywhere in the world.
a.
Uniform Resource Locators (URLs)
c.
Dynamic Host Configuration Protocol
b.
Domain Name Systems (DNSs)
d.
XMLs
 

 15. 

The protocol that resides at the ____ layer in the TCP/IP protocol suite is called Internet Protocol (IP).
a.
application
c.
network
b.
transport
d.
network access
 

 16. 

The ____ field of an IP datagram contains the version number of IP being used, just in case a new version becomes available.
a.
Service Type
c.
Protocol
b.
Time to Live
d.
Version
 

 17. 

The TCP header ____ field contains a 32-bit value that counts bytes and indicates a packet’s data position within the connection.
a.
Source Port
c.
Sequence Number
b.
Padding
d.
Window
 

 18. 

____ takes an IP address in an IP datagram and translates it into the appropriate medium access control layer address for delivery on a local area network.
a.
Transport Control Protocol (TCP)
c.
Network Address Translation (NAT)
b.
User Datagram Protocol (UDP)
d.
Address Resolution Protocol (ARP)
 

 19. 

____ lets a router represent an entire local area network to the Internet as a single IP address.
a.
ICMP
c.
ARP
b.
NAT
d.
UDP
 

 20. 

A ____ is a data network connection that makes use of the public telecommunications infrastructure but maintains privacy through the use of a tunneling protocol and security procedures.
a.
NAT network
c.
DHCP
b.
TCP network
d.
virtual private network (VPN)
 

 21. 

The Point-to-Point Tunneling Protocol (PPTP) is an extension of the Internet’s ____.
a.
Internet Protocol (IP)
c.
Point-to-Point Protocol (PPP)
b.
Transport Control Protocol (TCP)
d.
Address Resolution Protocol (ARP)
 

 22. 

A(n) ____ uniquely identifies files, Web pages, images, or any other types of electronic documents that reside on the Internet.
a.
File Transfer Protocol (FTP)
c.
Uniform Resource Locator (URL)
b.
Internet Protocol (IP)
d.
Domain Name Service (DNS)
 

 23. 

The ____ is a large, distributed database of Internet addresses and domain names.
a.
Uniform Resource Locator (URL)
c.
Hypertext Transfer Protocol (HTTP)
b.
Domain Name System (DNS)
d.
Hypertext Markup Language (HTML)
 

 24. 

____ is the computerized version of writing a letter and mailing it at the local post office.
a.
FTP
c.
e-commerce
b.
e-business
d.
Electronic mail
 

 25. 

The ____ is an Internet protocol for sending and receiving e-mail and is used to perform the transfer.
a.
Address Resolution Protocol (ARP)
c.
File Transfer Protocol (FTP)
b.
Simple Mail Transfer Protocol (SMTP)
d.
Transport Control Protocol (TCP)
 

 26. 

____ is a client/server protocol in which e-mail is received and held for you at your Internet server.
a.
Hypertext Transfer Protocol (HTTP)
b.
File Transfer Protocol (FTP)
c.
Domain Name Service (DNS)
d.
Internet Message Access Protocol (IMAP)
 

 27. 

The primary functions of ____ are to allow a user to download a file from a remote site to the user’s computer and to upload a file from the user’s computer to a remote site.
a.
Hypertext Transfer Protocol (HTTP)
b.
Domain Name Service (DNS)
c.
File Transfer Protocol (FTP)
d.
Internet Message Access Protocol (IMAP)
 

 28. 

____ is a terminal emulation program for TCP/IP networks, such as the Internet, that allows users to log in to a remote computer.
a.
Remote login
c.
DNS
b.
ARP
d.
FTP
 

 29. 

The practice of making telephone calls over the Internet has had a number of different names, including packet voice, voice over packet, voice over the Internet, Internet telephony, and ____.
a.
HTML
c.
Voice over IP (VoIP)
b.
SMTP
d.
XHTML
 

 30. 

____ is a common application layer protocols that servers and the Internet use to deliver streaming audio and video data to a user’s browser.
a.
Secure Shell (SSH)
c.
Real-Time Protocol (RTP)
b.
Transport Control Protocol (TCP)
d.
Voice over IP (VoIP)
 

 31. 

One of the biggest changes to affect the Internet will be the adoption of a new version of the Internet Protocol, version ____.
a.
IPv3
c.
IPv5
b.
IPv4
d.
IPv6
 

 32. 

The local loop commonly consists of either four or ____ wires.
a.
six
c.
nine
b.
eight
d.
ten
 

 33. 

As long as a telephone call remains within a LATA (a(n) ____ call), the telephone call is local and is handled by a local telephone company.
a.
intraLATA
c.
outerLATA
b.
extraLATA
d.
outLATA
 

 34. 

If the telephone call passes out of one LATA and into another (a(n) ____ call), the telephone call is long distance and must be handled by a long-distance telephone company.
a.
intraLATA
c.
inLATA
b.
innerLATA
d.
interLATA
 

 35. 

A(n) ____ is a service from local telephone companies in which up-to-date telephone facilities at the telephone company’s central (local) office are offered to business users, so that they don’t need to purchase their own facilities.
a.
local exchange carriers (LECs)
c.
interexchange carriers (IECs or IXCs)
b.
central office exchange service
d.
private branch exchange (PBXs)
 

 36. 

The Telecommunications Act of 1996 mandated that the existing local telephone companies, now called ____, must give CLECs access to their telephone lines.
a.
private Branch Exchange (PBX)
b.
Centrex (central office exchange service)
c.
incumbent local exchange carriers (ILECs)
d.
interexchange carriers (IECs)
 

 37. 

A(n) ____ connection has a faster downstream transmission speed than its upstream speed.
a.
symmetric
c.
asymmetric
b.
static
d.
dynamic
 

 38. 

Because DSL is an always-on connection, it uses a ____ circuit instead of a switched circuit.
a.
changing
c.
virtual
b.
dynamic
d.
permanent
 

 39. 

Digital subscriber line comes in a variety of formats. Often collectively referred to as ____.
a.
ADSL
c.
SDSL
b.
CDSL
d.
xDSL
 

 40. 

____ is a popular format that transmits the downstream data at a faster rate than the upstream rate.
a.
Asymmetric digital subscriber line (ADSL)
b.
Consumer DSL (CDSL)
c.
DSL Lite
d.
High bit-rate DSL (HDSL)
 

 41. 

When a customer establishes a permanent virtual circuit with a frame relay carrier, both customer and carrier agree on a data transfer rate called the ____.
a.
bit rate
c.
committed information rate (CIR)
b.
PVC rate
d.
LATA rate
 

 42. 

The ____ allows the customer to exceed the committed information rate by a fixed amount for brief moments of time.
a.
bit rate
c.
committed information rate (CIR)
b.
burst rate
d.
LATA rate
 

 43. 

____ is the most expensive ATM class of service.
a.
Variable bit rate (VBR)
c.
Unspecified bit rate (UBR)
b.
Available bit rate (ABR)
d.
Constant bit rate (CBR)
 

 44. 

____ is capable of sending traffic that may experience bursts of data, but there are no promises as to when the data may be sent.
a.
Variable bit rate (VBR)
c.
Unspecified bit rate (UBR)
b.
Available bit rate (ABR)
d.
Constant bit rate (CBR)
 

 45. 

____ means that different icons on a computer screen represent common PBX functions such as call hold, call transfer, and call conferencing, making the system easier for operators to use.
a.
Third-party call control
c.
Fax-back
b.
PBX graphic user interface
d.
Call filtering
 

 46. 

____ means that users can specify telephone numbers that are allowed to get through.
a.
PBX graphic user interface
c.
Fax-back
b.
Customized menuing system
d.
Call filtering
 

 47. 

Many people consider the Trojan horse to be a form of computer ____.
a.
virus
c.
router
b.
firewall
d.
switch
 

 48. 

A ____ virus is a common type of virus that is programmed into an attached macro file.
a.
boot sector
c.
polymorphic
b.
macro
d.
file infector
 

 49. 

A ____ is a common Internet tool used to verify if a particular IP address of a host exists and to see if the particular host is currently available.
a.
ping
c.
router
b.
firewall
d.
DNS
 

 50. 

____ may be considered a form of physical protection.
a.
Router
c.
Trojan horses
b.
Worms
d.
Surveillance
 

 51. 

____ involves electronically monitoring data flow and system requests into and out of their systems.
a.
Worms
c.
Firewalls
b.
Intrusion detection
d.
Routers
 

 52. 

Perhaps the most common form of protection from unauthorized use of a computer system is the ____.
a.
password
c.
PKI
b.
certificate
d.
digital signature
 

 53. 

____ is data before any encryption has been performed.
a.
Plaintext
c.
Encriptext
b.
Ciphertext
d.
Cryptotext
 

 54. 

Possibly the earliest example of a polyalphabetic cipher is the ____ cipher.
a.
Caesars
c.
Enigma
b.
Roman
d.
Vigenére
 

 55. 

The opposite of asymmetric encryption is ____ encryption, in which one key is used to encrypt and decrypt.
a.
available key
c.
symmetric
b.
asymmetric key
d.
public key
 

 56. 

____ is a set of protocols created to support the secure transfer of data at the IP layer.
a.
Transport Layer Security (TLS)
c.
Date Encryption Standard (DES)
b.
IPsec (IP security)
d.
Advanced Encryption Standard (AES)
 

 57. 

____ is high-quality encryption software that has become quite popular for creating secure e-mail messages and encrypting other types of data files for average users.
a.
DES
c.
3DES
b.
PGP
d.
AES
 

 58. 

____ spread spectrum spreads the transmission of a signal over a wide range of frequencies using mathematical values.
a.
Frequency hopping
c.
Time hopping
b.
Direct sequence
d.
Amplitude sequence
 

 59. 

The first security protocol for wireless LANs was ____.
a.
Wi-Fi Protected Access (WPA)
c.
IPsec
b.
Wired Equivalency Protocol (WEP)
d.
IEEE 802.11i
 

 60. 

IEEE ____ addresses both weaknesses of WEP by allowing the keys, encryption algorithms, and negotiation to be dynamically assigned, and by adopting the AES encryption based on the Rijndael algorithm with 128-, 192-, or 256-bit keys.
a.
802.11a
c.
802.11g
b.
802.11b
d.
802.11i
 

Completion
Complete each statement.
 

 1. 

A(n) _________________________ is a collection of computers and computer-related equipment interconnected to perform a given function or functions and typically using local and long-distance telecommunications systems.
 

 

 2. 

A(n) ____________________ is a device that allows one or more stations to access the physical network and is a transfer point for passing information through the network.
 

 

 3. 

In a network graph, the edge between each pair of nodes can be assigned a weight or associated cost to form a structure called a(n) _________________________.
 

 

 4. 

____________________ states that each node takes the incoming packet and retransmits it onto every outgoing link.
 

 

 5. 

During the late 1960s, ARPA created one of the country’s first wide area packet-switched networks, the ____________________.
 

 

 6. 

____________________ lines and tie lines are leased telephone lines that require no dialing.
 

 

 7. 

The ______________________________ paved the way for anybody to offer a local telephone service to homes and businesses.
 

 

 8. 

A(n) ____________________ is a high-speed communications service that allows high-speed access to wide area networks such as the Internet via a cable television connection.
 

 

 9. 

______________________________ means that when a customer calls your company, his or her telephone number is used to extract the customer’s records from a corporate database.
 

 

 10. 

In ____________________, a perpetrator sends an excessive amount of unwanted e-mail messages to someone.
 

 

 11. 

In computer terminology, a(n) ____________________ is a trap that is set by network personnel in order to detect unauthorized use of a network resource.
 

 

 12. 

The ____________________ is the data after the encryption algorithm has been applied.
 

 

 13. 

In an effort to create an encryption scheme that could be used by the average person, an entrepreneur named Philip Zimmermann created encryption software called _________________________.
 

 

 14. 

____________________ is the art and science of hiding information inside other, seemingly ordinary messages or documents.
 

 

 15. 

A(n) ____________________ is a system or combination of systems that supports an access control policy between two networks.
 

 



 
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