Chapter 15 - Data Networks

Question 1

Network architecture can be described as the ___ grouping of hardware, software, and applications.

a. Structured
b. Logical
c. Top down
d. Efficient

Answer 1

a. Structured

p 15-1

Network architecture can be described as the structured grouping of hardware, software, and applications. The successful integration of these three elements allows for the transfer of all types of information between users, administrators, and devices.

Question 2

A(n) ___ can be defined as two or more networked devices and the associated software, peripherals, operators, physical processes, and media that form an autonomous unit capable of processing and transferring data.

a. Network
b. Application
c. System
d. Stack

Answer 2

c. System

p 15-3

A system can be defined as two or more networked devices and the associated software, peripherals, operators, physical processes, and media that form
an autonomous unit capable of processing and transferring data.

This broad definition of a system makes it possible to use the OSI model to describe any type of network, from a residential LAN to the Internet.

Question 3

Name the 7 OSI layers

Answer 3

(7) Application
(6) Presentation
(5) Session
(4) Transport
(3) Network
(2) Data Link
(1) Physical

Mnemonic Please Do Not Touch Steve’s Pet Alligator to remember the seven layers (starting at Layer 1 and moving up to Layer 7).

Question 4

The term ___ is also used to describe the improved network reliability enabled by clustering.

a. Failover access
b. Centralized
c. High availability
d. Full flexibility

Answer 4

c. High availability

p 15-10

The term high availability is also used to describe the improved network reliability enabled by clustering.

Failure of any single server results in the transfer of all activities from the failed server to one or more of the other servers in the cluster, a process referred to as failover access.

Question 5

Each port on a switch is a separate communications channel, representing a different ___ domain.

a. Collision
b. Broadcast
c. Routing
d. Segment

Answer 5

a. Collision

p 15-10

Each port on a switch is a separate communications channel, representing a different collision domain. This makes it possible for multiple devices on a switch-based network to transmit simultaneously as long as they are connected to different ports on the switch.

NOTE: A port on a switch is often described as a dedicated connection.

Question 6

___ layer switching provides increased flexibility to network administrators, making it possible for them to direct, modify, and refine network traffic flows on the basis of organizational priorities.

a. Simplified
b. Higher
c. Lower
d. Data

Answer 6

b. Higher

p 15-12

This process is sometimes described as traffic engineering or traffic shaping.

Question 7

An incoming frame on a Layer 3 switch is processed on the basis of ___ address information.

a. Routing
b. Switching
c. Layer 2
d. Layer 3

Answer 7

d. Layer 3

p 15-12

An incoming frame on a Layer 3 switch is processed on the basis of Layer 3 address information found in the data field of the Layer 2 frame. In some cases, an even greater level of detail can be extracted and used to forward a frame. For example, a Layer 4 switch directs frames on the basis of OSI Layer 4 (Transport layer) protocol information and a Layer 7 (Application layer) switch processes frames on the basis of the applications used to generate the frames.

Question 8

Layer ___ services make it possible for applications running on dissimilar systems to use a network to exchange information.

a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7

Answer 8

g. 7

p 15-5

Application - Layer 7 services make it possible for applications running on dissimilar systems to use a network to exchange information. Services defined by this layer include file transfer, message handling, and remote management.

Question 9

Layer ___ services are responsible for various forms of data conversion.

a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7

Answer 9

f. 6

p 15-5

Presentation - Layer 6 services are responsible for various forms of data conversion. This layer negotiates and establishes a common form for data representation, which includes character code translations, data compression, and message encryption.

Question 10

Layer ___ services are responsible for synchronizing and managing data transfer between network devices.

a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7

Answer 10

e. 5

p 15-5

Session - Layer 5 services are responsible for synchronizing and managing data transfer between network devices. For example, a Layer 5 protocol can direct a device to start, stop, restart, or abandon data transfer activity.

Question 11

Layer ___ services make it possible to assign various levels of quality to the data transfer process

a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7

Answer 11

d. 4

p 15-5c. 3

p 15-5

Transport - Layer 4 services make it possible to assign various levels of quality to the data transfer process. When a connection is being established between network devices, the Layer 4 protocol can be used to select a particular class of service.

This layer also can monitor the transfer for billing purposes, ensure that the appropriate service quality is maintained, and generate an alert if this quality has been compromised.

Question 12

Layer ___ services are responsible for internetwork data transfer (e.g., between LANs connected to the Internet).

a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7

Answer 12

c. 3

p 15-5

Network - Layer 3 services are responsible for internetwork data transfer (e.g., between LANs connected to the Internet).

If multiple routes exist between the networks, a Layer 3 protocol can choose the most appropriate one based on such criteria as message priority, route congestion, or route cost.

Question 13

Layer ___ services are responsible for intranetwork datatransfer (e.g., between devices connected to a LAN).

a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7

Answer 13

b. 2

p 15-5

Data - Layer 2 services are responsible for intranetwork data transfer (e.g., between devices connected to a LAN). Some of the functions of a Layer 2 protocol include device identification and managed access to a shared transmission channel.

Question 14

Layer ___ services are responsible for the transfer of information over various media.

a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7

Answer 14

a. 1

p 15-5

Physical - Layer 1 services are responsible for the transfer of information over various media.

Question 15

In regards to videoconferencing, data received before it can be processed by a videoconferencing application is typically stored in an allocated zone in the station’s memory, referred to as a ___.

a. Broadcast
b. Reserve
c. Buffer
d. Domain

Answer 15

c. Buffer

p 15-18

Data received before it can be processed by a videoconferencing application is typically stored in an allocated zone in the station’s memory, referred to as a buffer.

Question 16

Class 4 can also be provided without redundancy at the component level. This requires a configuration of:

a. 2(N+1)
b. 2(N+2)
c. 2(N+N)
d. 2N

Answer 16

c. 2(N+N)

p 15-24

Class 4 can also be provided without redundancy at the component level. This requires a configuration of 2(N+N) instead of 2(N+1), which is typically the equivalent to two separate Class 3 networks.

Question 17

The OSI model uses an approach called ___ to illustrate and explain the message exchange process.

a. Listing
b. Sequencing
c. Layering
d. Stacking

Answer 17

c. Layering

p 15-5

The OSI model uses an approach called layering to illustrate and explain the message exchange process. This approach divides the various functions and services provided by a network into discrete groupings called layers.

Question 18

In the Open Systems Interconnection (OSI) Reference Model, ___ are the connection points between layers.

a. Stacks
b. Service access points
c. Transition layers
d. Peer-to-peer links

Answer 18

b. Service access points

p 15-6 & Figure 15-4

Services access points are the connection points between layers.

The layers in the OSI model are commonly described as being connected to each other in vertical form, also called a stack or protocol stack.

Question 19

An excessive number of _____ serves as the practical limit for the total number of devices that can be connected to switches on a local area network (LAN).

a. Applications
b. Retransmissions
c. Broadcasts
d. Collisions

Answer 19

c. Broadcasts

p 15-14

The greater the number of devices on a LAN, the greater the number of broadcasts issued. An excessive number of broadcasts serves as a practical limit for the total number of devices that can be connected to a LAN, even when all of the connections are switched.

Question 20

Broadcast domains can also be referred as:

a. Collision domains
b. Internetworks
c. Mesh configurations
d. Subnetworks

Answer 20

d. Subnetworks

p 15-10

Routing is used to interconnect various types of LANs at Layer 3 of the OSI model. Routers make it possible to segment an organizational network into multiple broadcast domains, also referred to as subnetworks or subnets, using Layer 3 address assignments

Question 21

Client software is used to link a station’s network interface card (NIC) to the operating system (OS), making it possible for the OS to communicate with the NIC.

a. True
b. False

Answer 21

False

p 15-13

Drivers are needed to link a station’s NIC to the OS, making it possible for the OS to communicate with the NIC.

Question 22

When designing a network, the ___ design process is used in cases where detailed network characteristics are not available.

a. Structured
b. Physical
c. Logical
d. Functional

Answer 22

b. Physical

p 15-20

Physical design is also referred to as bottom-up design.

Functional design also is referred to as top-down des

Question 23

On a conventional local area network, there is a single broadcast domain, spanning all of the hubs and switches as well as the devices connected to their ports. Such configurations are referred to as _____ networks.

a. Shared
b. Global
c. Logical
d. Flat

Answer 23

d. Flat

p 15-14

On a conventional LAN, there is a single broadcast domain, spanning all of the hubs and switches as well as the devices connected to their ports. Such configurations are referred to as flat networks.

Question 24

In a server cluster, failure of any single server results in the transfer of all activities from the failed server to one or more of the other servers in the cluster, a process referred to as:

a. Hot swap
b. Failover access
c. Fault tolerance
d. Switching

Answer 24

b. Failover access

p 15-10

Failure of any single server results in the transfer of all activities from the failed server to one or more of the other servers in the cluster, a process referred to as failover access.

Question 25

Based on the number of stations simultaneously receiving video content and the direction of transfer of the video content, _____ types of network video communications can be identified.

a. Eight
b. Six
c. Four
d. Two

Answer 25

c. Four

p 15-17

Video services can be classified using the following criteria:
• The number of stations simultaneously receiving the same video content from the sending device, which can be one (i.e., PTP) or more than one (i.e., point-to-multipoint)
• The direction of transfer of the video content, which can be one-way (i.e., unidirectional) or two-way (i.e., bidirectional)

Question 26

Each port on a network switch serves as a separate _____ channel.

a. Collision
b. Network
c. Broadcast
d. Communications

Answer 26

d. Communications

p 15-10

Each port on a switch is a separate communications channel, representing a different collision domain.

Question 27

The Open Systems Interconnection (OSI) Reference Model specifies the sequence of _____ required for network message transfer between applications running on different systems.

a. Tasks
b. Communications
c. Processes
d. Steps

Answer 27

c. Processes

p 15-4

The objective of the OSI model is to provide a structured approach for the development of all types of networks. The model specifies the sequence of Processes required for network message transfer between applications running on different systems.

Question 28

On a conventional local area network, there is a single _____ domain, spanning all of the switches as well as the devices connected to their ports.

a. Administrative
b. Contention
c. Collision
d. Broadcast

Answer 28

d. Broadcast

p 15-14

On a conventional LAN, there is a single broadcast domain, spanning all of the hubs and switches as well as the devices connected to their ports. Such configurations are referred to as flat networks.

Question 29

Which one of the following computer room cabling topologies uses the least amount of cabling?

a. Top-of-rack
b. In-row
c. End-of-row
d. Centralized

Answer 29

a. Top-of-rack

p 15-32

The top-of-rack topology uses the least amount of cabling since only a single cable is required from a centralized switch to the switch in each rack or cabinet containing servers and storage devices. However, switches must be installed and managed in every rack or cabinet in the CR.

Question 30

In the Open Systems Interconnection (OSI) Reference Model, each layer provides services to:

a. Any other layer
b. Both the layers above and below
c. The layer below
d. The layer above

Answer 30

d. The layer above

p 15-6

In the OSI model, each layer provides services to the layer above while hiding from that layer the processes used to implement the services.

Question 31

In a data center, _____ allows multiple servers to be housed within the same physical host without compromising the benefits of being a separate physical server.

a. Centralization
b. Swapping
c. Clustering
d. Virtualization

Answer 31

d. Virtualization

p 15-9

Virtualization allows multiple servers to be housed within the same physical host without compromising the benefits of being a separate physical server.

Question 32

Ideally, changes can be made to any layer in the Open Systems Interconnection (OSI) Reference Model without requiring changes to:

a. Any other layer
b. The layer below
c. The layer above

Answer 32

a. Any other layer

p 15-6

In the OSI model, each layer provides services to the layer above while hiding from that layer the processes used to implement the services.

Ideally, changes can be made to any layer without requiring changes to any of the other layers as long as the inputs and outputs of the changed layer remain the same.

Question 33

Routers make it possible to segment an organizational network into multiple _____ domains.

a. Collision
b. Communications
c. Signaling
d. Broadcast

Answer 33

d. Broadcast

p 15-10

Routers make it possible to segment an organizational network into multiple broadcast domains, also referred to as subnetworks or subnets, using Layer 3 address assignments.

Question 34

When compared to other computer room topologies, the centralized topology uses ___ switches than the other topologies.

a. More
b. Fewer

Answer 34

b. Fewer

p 15-30

Question 35

The Open Systems Interconnection (OSI) Reference Model can be used to describe:

a. Any type of network
b. Local area networks
c. Wide area networks

Answer 35

a. Any type of network

p 15-4

This broad definition of a system makes it possible to use the OSI model to describe any type of network, from a residential LAN to the Internet.

Question 36

The physical paths of the access provider connections to a data center entrance room shall be a minimum of _____ apart along their entire routes.

a. 25 m (82 ft)
b. 20 m (66 ft)
c. 15 m (49 ft)
d. 10 m (33 ft)

Answer 36

b. 20 m (66 ft)

p 15-22

Typically, service is provided from two different points-of-presence that are at least ≈20 m (66 ft) apart.

The physical paths of the AP connections are then also a minimum of ≈20 m (66 ft) apart along their entire routes.

Question 37

Ideally, changes can be made to any layer in the Open Systems Interconnection (OSI) Reference Model without requiring changes to:

a. Any other layer
b. Both the layers above and below
c. The layer below
d. The layer above

Answer 37

a. Any other layer

p 15-6

In the OSI model, each layer provides services to the layer above while hiding from that layer the processes used to implement the services. Ideally, changes can be made to any layer without requiring changes to any of the other layers as long as the inputs and outputs of the changed layer remain the same.

Question 38

Multiple entrance rooms (ERs) are required for ___ data center infrastructures.

a. Class 4
b. Class 3 or higher
c. Class 2 or higher
d. Class 1 or higher

Answer 38

b. Class 3 or higher

p 5-23 Figure 15.12

Question 39

Route congestion and message priority are a few of the functions of what layer of the OSI Model?

a. Layer 1
b. Layer 2
c. Layer 3
d. Layer 4

Answer 39

c. Layer 3

p 15-5

A Layer 3 protocol can choose the most appropriate one based on such criteria as message priority, route congestion, or route cost.