Module 6

Question 1

The ______ is responsible for
communications between end-device
network interface cards.

Answer 1

Data Link Layer

Question 2

Data Link Layer allows upper layer protocols to access
the physical layer media and
encapsulates Layer 3 packets (IPv4
and IPv6) into _____

Answer 2

layer 2 Frames

Question 3

_____ also performs error detection and
rejects corrupts frames.

Answer 3

Data Link Layer

Question 4

The Data Link Layer consists of two
sublayers.

Answer 4

• Logical Link Control (LLC)
• Media Access Control (MAC)

Question 5

_____ sublayer communicates
between the networking software at the
upper layers and the device hardware at
the lower layers.

Answer 5

LLC (Logical Link Control)

Question 6

______ sublayer is responsible for
data encapsulation and media access
control.

Answer 6

MAC (Media Access Control)

Question 7

______ exchanged between nodes may experience numerous data
link layers and media transitions.

Answer 7

Packets

Question 8

At each hop along the path, a router performs four basic Layer 2
functions:

Answer 8

• Accepts a frame from the network medium
• De-encapsulates the frame to expose the encapsulated packet
• Re-encapsulates the packet into a new frame
• Forwards the new frame on the medium of the next network segment

Question 9

Data link layer protocols are
defined by engineering
organizations:

Answer 9

• Institute for Electrical and Electronics Engineering (IEEE)
• International Telecommunications Union (ITU)
• International Organizations for Standardization (ISO)
• American National Standards Institute (ANSI)

Question 10

The ______ is the arrangement and relationship of the network
devices and the interconnections between them.

Answer 10

topology of a network

Question 11

There are two types of topologies used when describing networks:

Answer 11

• Physical Topology
• Logical Topology

Question 12

shows physical connections and how devices are
interconnected.

Answer 12

Physical Topology

Question 13

– identifies the virtual connections between devices
using device interfaces and IP addressing schemes

Answer 13

Logical Topology

Question 14

There are three common physical WAN topologies:

Answer 14

• Point-to-point
• Hub and Spoke
• Mesh

Question 15

– the simplest and most common WAN topology. Consists of
a permanent link between two endpoints.

Answer 15

point-to-point

Question 16

similar to a star topology where a central site
interconnects branch sites through point-to-point links

Answer 16

Hub and Spoke

Question 17

provides high availability but requires every end system to be
connected to every other end system.

Answer 17

Mesh

Question 18

____- topologies directly connect two nodes.

Answer 18

Physical point-to-point

Question 19

The nodes may not share the media with other hosts.

Answer 19

Point-to-Point WAN Topology

Question 20

Because all frames on the media can only travel to or from the two
nodes, _____ protocols can be very simple.

Answer 20

Point-to-Point WAN

Question 21

_____ on LANs are typically
interconnected using a star or extended
star topology.

Answer 21

End devices

Question 22

_____
topologies are easy to install, very scalable
and easy to troubleshoot.

Answer 22

Star and extended star

Question 23

Early Ethernet and Legacy Token Ring
technologies provide two additional
topologies:

Answer 23

• Bus
• Ring

Question 24

All end systems chained
together and terminated on each end.

Answer 24

Bus

Question 25

– Each end system is connected to its respective neighbors to form a ring.

Answer 25

ring

Question 26

- Only allows one device to send or receive at a time on a shared medium. * Used on WLANs and legacy bus topologies with Ethernet hubs.

Answer 26

Half-duplex communication

Question 27

* Allows both devices to simultaneously transmit and receive on a shared medium. * Ethernet switches operate in full-duplex mode.

Answer 27

Full-duplex communication

Question 28

All nodes operating in half-duplex, competing for use of the medium. Examples are: * Carrier sense multiple access with collision detection (CSMA/CD) as used on legacy bus-topology Ethernet. * Carrier sense multiple access with collision avoidance (CSMA/CA) as used on Wireless LANs.

Answer 28

Contention-based access

Question 29

* Deterministic access where each node has its own time on the medium. * Used on legacy networks such as Token Ring and ARCNET.

Answer 29

Controlled Access

Question 30

* Used by legacy Ethernet LANs. * Operates in half-duplex mode where only one device sends or receives at a time. * Uses a collision detection process to govern when a device can send and what happens if multiple devices send at the same time.

Answer 30

CSMA/CD

Question 31

* Devices transmitting simultaneously will result in a signal collision on the shared media. * Devices detect the collision. * Devices wait a random period of time and retransmit data.

Answer 31

CSMA/CD collision detection process

Question 32

* Used by IEEE 802.11 WLANs. * Operates in half-duplex mode where only one device sends or receives at a time. * Uses a collision avoidance process to govern when a device can send and what happens if multiple devices send at the same time.

Answer 32

CSMA/CA

Question 33

* When transmitting, devices also include the time duration needed for the transmission. * Other devices on the shared medium receive the time duration information and know how long the medium will be unavailable.

Answer 33

CSMA/CA collision avoidance process

Question 34

_____ is encapsulated by the data link layer with a header and a trailer to form a frame

Answer 34

Data

Question 35

A data link frame has three parts:

Answer 35

- Header - Data - Trailer

Question 36

Identifies beginning and end of frame

Answer 36

Frame Start and Stop

Question 37

Indicates source and destination nodes

Answer 37

Addressing

Question 38

Identifies encapsulated layer 3 protocol

Answer 38

Type

Question 39

Identifies flow control services

Answer 39

Control

Question 40

Contains the frame payload

Answer 40

Data

Question 41

Used for determine transmission errors

Answer 41

Error Detection

Question 42

* Also referred to as a physical address. - Contained in the frame header - Used only for local delivery of a frame on the link - Updated by each device that forwards the frame

Answer 42

Layer 2 Addresses

Question 43

The logical topology and physical media determine the data link protocol used:

Answer 43

- Ethernet - 802.11 Wireless - Point-to-Point (PPP) - High-Level Data Link Control (HDLC) - Frame-Relay