Chapter 1 TextBook

Question 1

What are the three forces driving the evolution of data communications and networking facilities?

Answer 1

Traffic growth, development of new services, advances in technology

Question 2

How has communication traffic changed over the decades?

Answer 2

It has grown at a high and steady rate, now including voice, data, image, and video

Question 3

What is the impact of the increasing demand for web services and mobile access on businesses?

Answer 3

Businesses are pressured to increase communication capacity in cost-effective ways

Question 4

What has caused the explosion of mobile broadband traffic?

Answer 4

Increased data demand from smartphones and tablets, along with high-quality service expectations

Question 5

What are the four notable technology trends in data communications?

Answer 5

• Faster and cheaper computing and communications
• More intelligent networks
• Dominance of the Internet and Web applications
• Mobility as a new frontier for ICT

Question 6

What does QoS stand for in networking?

Answer 6

Quality of Service

Question 7

What is the significance of dense wavelength division multiplexing (DWDM)?

Answer 7

It enables communication traffic to be carried by fiber optic cables at rates of multiple terabits per second

Question 8

How often does Internet backbone data rate demand typically double?

Answer 8

Approximately every 18 months

Question 9

True or False: Today’s networks can provide customizable services in network management and security.

Answer 9

True

Question 10

What characterizes the migration to ‘everything over IP’?

Answer 10

Opportunities and challenges for ICT managers in reaching customers, suppliers, and partners

Question 11

Fill in the blank: The trend of _______ has liberated workers from the confines of the physical enterprise.

Answer 11

mobility

Question 12

What percentage of traffic typically remains local in a business environment?

Answer 12

About 80%

Question 13

What are two examples of consumer electronics driving increased traffic on networks?

Answer 13

• Digital versatile disks (DVDs)
• Digital still cameras

Question 14

What is convergence in the context of telecommunications?

Answer 14

The merger of previously distinct telephony and information technologies and markets

Question 15

What are the three layers of the convergence model?

Answer 15

• Applications
• Enterprise services
• Infrastructure

Question 16

What key aspect of infrastructure convergence allows voice, image, and video to be carried over networks?

Answer 16

Packet-based transmission using the Internet Protocol (IP)

Question 17

What has driven the emergence of high-speed LANs in business environments?

Answer 17

The widespread acceptance of personal computers and the need for high-speed data transfer

Question 18

What are server farms used for in high-speed LANs?

Answer 18

To allow client systems to draw large amounts of data from centralized servers

Question 19

What has changed in corporate wide area networking needs since the early 1990s?

Answer 19

A shift from centralized computing to more dispersed employee locations and telecommuting

Question 20

What type of applications have increased reliance on personal computers and servers?

Answer 20

Client/server computing and intranet computing

Question 21

What does convergence in telecommunications involve?

Answer 21

Moving voice into a data infrastructure and integrating all voice and data networks into a single data network infrastructure

This includes extending the network into wireless communication.

Question 22

What is the fundamental purpose of a communications system?

Answer 22

The exchange of data between two parties.

Question 23

What are the key elements of a communications model?

Answer 23

• Source
• Transmitter
• Transmission system
• Receiver
• Destination

Question 24

What role does a transmitter play in a communications model?

Answer 24

Transforms and encodes the information to produce electromagnetic signals for transmission.

Question 25

What is the function of a receiver in a communications model?

Answer 25

Accepts the signal from the transmission system and converts it into a form that can be handled by the destination device.

Question 26

What is transmission system utilization?

Answer 26

Making efficient use of transmission facilities shared among multiple communicating devices.

Question 27

What is multiplexing?

Answer 27

Techniques used to allocate the total capacity of a transmission medium among multiple users.

Question 28

What is error detection and correction in data communications?

Answer 28

Processes required to identify and fix errors in transmitted signals.

Question 29

What is flow control?

Answer 29

Ensures that the source does not overwhelm the destination by sending data too quickly.

Question 30

What does addressing refer to in a communications system?

Answer 30

Indicating the identity of the intended destination for transmitted data.

Question 31

What is routing in data communications?

Answer 31

Choosing a specific path through a network for data transmission.

Question 32

What is the difference between error correction and recovery?

Answer 32

Error correction fixes errors in data, while recovery techniques resume interrupted information exchanges.

Question 33

What is message formatting?

Answer 33

Agreement on the form of the data to be exchanged or transmitted.

Question 34

What is the significance of network management in data communications?

Answer 34

Needed to configure, monitor, and manage the communication system effectively.

Question 35

What are the major transmission media used in data communications?

Answer 35

* Twisted-pair lines * Coaxial cable * Optical fiber cable * Terrestrial and satellite microwave

Question 36

What is the impact of fiber optic communication on data transmission?

Answer 36

Offers high capacity and security, leading to its widespread adoption in long-distance and local communications.

Question 37

What is the trend towards wireless transmission in communications?

Answer 37

Supports universal personal telecommunications and access to communications.

Question 38

What are the two major approaches to increasing transmission efficiency?

Answer 38

* Multiplexing * Compression

Question 39

Fill in the blank: The basic building block of any enterprise network infrastructure is the _______.

Answer 39

[transmission line]

Question 40

True or False: The properties of the signal must allow it to be propagated through the transmission system and be interpretable at the receiver.

Answer 40

True

Question 41

What must be established for effective communication between the transmitter and receiver?

Answer 41

Synchronization between the two parties.

Question 42

What is the role of a modem in data communications?

Answer 42

Converts digital signals from a computer into analog signals for transmission over telephone networks.

Question 43

What is the purpose of encoding information into an electromagnetic signal?

Answer 43

To determine how information is transmitted, affecting performance and reliability.

Question 44

What must be agreed upon between a device and the transmission medium?

Answer 44

The interface.

Question 45

What functions are performed by a data link control protocol?

Answer 45

Controlling the flow of information and recovering from its loss or corruption.

Question 46

What are the two main objectives to maximize transmission efficiency?

Answer 46

* Maximize information carried over a resource * Minimize transmission capacity needed.

Question 47

What are the three most common multiplexing techniques?

Answer 47

* Frequency division * Synchronous time division * Statistical time division.

Question 48

What was the forecasted number of Internet users in 2016?

Answer 48

Approximately 3 billion users.

Question 49

How many fixed and mobile networked devices were estimated in 2016?

Answer 49

Over 20 billion devices.

Question 50

What was the forecast for total annual Internet traffic in 2016?

Answer 50

From 372 exabytes to 1.3 zettabytes.

Question 51

What type of network is commonly found in medium- and large-size office buildings?

Answer 51

Local Area Network (LAN).

Question 52

What has contributed to the proliferation of LANs in enterprises?

Answer 52

Development of internationally recognized standards.

Question 53

What is the dominant LAN architecture?

Answer 53

Ethernet.

Question 54

What is integration in the context of LANs?

Answer 54

Communication equipment and networks dealing simultaneously with voice, data, image, and video.

Question 55

What are the two traditional technologies for WAN implementation?

Answer 55

* Circuit switching * Packet switching.

Question 56

What is a characteristic of circuit-switching networks?

Answer 56

A dedicated communications path is established between two stations.

Question 57

In packet-switching networks, what are the small chunks of data called?

Answer 57

Packets.

Question 58

What type of network was developed to take advantage of high data rates and low error rates?

Answer 58

Frame relay.

Question 59

What is the primary difference between frame relay and ATM?

Answer 59

Frame relay uses variable-length packets, while ATM uses fixed-length packets.

Question 60

What does ATM stand for?

Answer 60

Asynchronous Transfer Mode.

Question 61

What is the typical geographic scope of a LAN?

Answer 61

A single building or a cluster of buildings.

Question 62

What are the common configurations of LANs?

Answer 62

* Switched LANs * Wireless LANs.

Question 63

What is one of the advantages of wireless networks?

Answer 63

Mobility.

Question 64

When was the ARPANET developed?

Answer 64

1969.

Question 65

Who developed the protocols for internetworking that formed the basis for the Internet?

Answer 65

Vint Cerf and Bob Kahn.

Question 66

What does IP stand for?

Answer 66

Internet Protocol.

Question 67

What does a host refer to in the context of the Internet?

Answer 67

A computer connected to the Internet.

Question 68

What is the role of a router in the Internet?

Answer 68

To connect different networks and make routing decisions.

Question 69

What is Customer Premises Equipment (CPE)?

Answer 69

Telecommunications equipment located on the customer’s premises.

Question 70

What does CPE stand for?

Answer 70

Customer Premises Equipment ## Footnote Refers to telecommunications equipment located on the customer’s premises.

Question 71

Give examples of Customer Premises Equipment (CPE).

Answer 71

* Telephone handsets * Modems * Cable TV set-top boxes * Digital subscriber line routers

Question 72

What is an Internet Service Provider (ISP)?

Answer 72

A company that provides access to the Internet ## Footnote ISPs have the equipment and telecommunication line access required to have a POP.

Question 73

What does NAP stand for?

Answer 73

Network Access Point ## Footnote Major Internet interconnection points that tie ISPs together.

Question 74

List the original four Network Access Points (NAPs) in the United States.

Answer 74

* New York * Washington, D.C. * Chicago * San Francisco

Question 75

What is the role of a Network Service Provider (NSP)?

Answer 75

Provides backbone services to an Internet Service Provider (ISP).

Question 76

Define Point of Presence (POP).

Answer 76

A site with telecommunications equipment that allows users to connect to the ISP network.

Question 77

What is the typical connection speed of a T-1 circuit?

Answer 77

1.544 Mbps

Question 78

What is the typical connection speed of a T-3 circuit?

Answer 78

44.736 Mbps

Question 79

What is the 'local loop' in telecommunications?

Answer 79

Infrastructure between a provider’s installation and the site where the host is located.

Question 80

What type of cable is typically used in a residential DSL connection?

Answer 80

Copper telephone line

Question 81

What type of cable is typically used in a residential cable modem connection?

Answer 81

Coaxial cable

Question 82

What does the ISP provide to home users?

Answer 82

* Unique numeric IP address * Name resolution * Access to other ISP networks

Question 83

True or False: A local loop provider is always the same as the ISP.

Answer 83

False

Question 84

What is the primary service provided by a Network Access Point (NAP)?

Answer 84

Infrastructure to move data between connected networks.

Question 85

What technology is commonly used in modern NAPs?

Answer 85

ATM and Gigabit Ethernet

Question 86

What is the role of routers in an IP backbone network?

Answer 86

Provide connectivity to external networks and users.

Question 87

What is wavelength division multiplexing (WDM)?

Answer 87

A technology that allows multiple logical channels on an optical link.

Question 88

What are edge routers used for?

Answer 88

To connect external networks and users to the backbone.

Question 89

What is the capacity requirement range for aggregation routers by 2020?

Answer 89

200 Gbps to 400 Gbps per optical link

Question 90

What is the capacity requirement range for core routers by 2020?

Answer 90

400 Gbps to 1 Tbps per optical link

Question 91

What is a common connection type for small or medium-sized businesses to the Internet?

Answer 91

Ethernet LAN configuration

Question 92

Fill in the blank: Mobile devices connect to the Internet through the _______.

Answer 92

public cellular network

Question 93

What are the main components of an ISP network?

Answer 93

* Interconnected routers * High-speed links to the Internet

Question 94

What are some design issues related to telecommunications links?

Answer 94

* Signal encoding * Error control