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WorksheetsNetworking Week 8
Total questions: 27
Worksheet time: 15mins
A link where data can flow successfully in both directions at the same time is
operating in:
Half duplex mode
Full duplex mode
Simplex mode
Multiplex mode
A message is to be sent from a host on an Ethernet network to a host on a remote
network. What MAC address does the host use as the destination address in the frame
header?
The MAC address of the host on the remote network.
Its own MAC address.
The MAC address of the local switch.
The MAC address of the default gateway
A network with a point to point topology: (choose 2)
Has only 2 nodes
Must be run in half duplex mode
Can have a simpler form of media access control than a multi-access network
Is subject to collisions because it has a less sophisticated form of Layer 2
protocol
A physical network topology shows:
How devices are linked by cables or wireless connections
How the network is split into subnets
How access to the medium is controlled
How the layer 2 and layer 3 addresses are matched
Encapsulation at the data link layer involves
Adding a header
Adding a trailer
Adding a header and a trailer
Changing the IP address to a MAC address
How are data link layer Ethernet addresses normally written down?
In dotted decimal form
As groups of 2 or 4 hexadecimal digits
In binary as octets
In octal
How many bits are there in a data link layer Ethernet address?
16
32
48
64
128
How would a host on an Ethernet network detect that there is an incoming frame
starting to arrive?
Each frame starts with a preamble, originally used for synchronisation, and the
preamble ends with a frame start delimiter.
Frames arrive at fixed intervals so it can predict when the next frame will
arrive.
The destination address is the first field in the frame, so the host detects a
frame when it recognises its own address.
When there is no incoming frame the medium is completely clear, so the host
just checks for any activity.
The logical topology determines
The arrangement of PCs within a building
The method of media access control
The type of gateway router required
The layer 3 protocol to be used
What are the two sublayers of the data link layer?
Physical access and network access sublayers
Logical link control and network access sublayers
Logical link control and media access control sublayers
CSMA/CD sublayer and media access control sublayer
What is defined by IEEE 802.11
Ethernet
Wi-Fi
Token Ring
Logical link control
What is defined by IEEE 802.2
Ethernet
Wi-Fi
Token Ring
Logical link control
What is defined by IEEE 802.3
Ethernet
Wi-Fi
Token Ring
Logical link control
What is the protocol data unit at the data link layer?
Segment
Packet
Frame
Datagram
What is the purpose of the frame trailer?
Addressing
Error checking
Showing the frame length
Showing the layer 3 protocol used
What is true of the Point to Point Protocol?
It is commonly used on serial WAN links with only 2 nodes.
It is commonly used on LANs that are not subject to collisions.
It can be used only on fibre optic links.
PPP can be used only when IP is the layer 3 protocol.
PPP uses MAC addresses as layer 2 addresses
Which data link layer protocol allows hosts to negotiate multilink, authentication and
compression options?
Ethernet
PPP
HDLC
ISDN
Which factors are important when you choose the Layer 2 protocol for a network?
(Choose 3)
Whether it is a LAN or a WAN
Whether you will use cable or wireless
Whether you will use TCP or UDP
Whether you will connect to the Internet or not
The number of hosts on the network
Which is true of a token ring network? (choose 2)
It uses a non-deterministic method of media access control.
There should be no collisions because only the host that has the token can
place a message on the medium.
Its method of media access control has a higher overhead than that of an
Ethernet network.
It is more efficient than an Ethernet network because collisions are detected
more quickly.
Which is true of the non-deterministic approach to media access control?
It is first-come-first-served so you cannot predict the order in which hosts will
be able to place messages on the medium.
It uses token passing so that the order in which hosts place messages on the
medium is strictly controlled.
The hosts cannot determine whether or not there has been a collision on a
shared medium.
The medium is not shared, so collisions do not occur.
Which layer of the OSI model is the data link layer?
Layer 1
Layer 2
Layer 3
Layer 4
Layer 5
Which media access control method is used on Ethernet networks?
Token passing
CSMA/CD
CSMA/CA
MAC addresses
Which of the following are characteristics of Ethernet? (Choose 3)
Uses tokens to control access to the medium
First come-first served access to the medium
Deterministic access to the medium
Contention-based access to the medium
Collisions can occur
Which of the following names are used for the addresses used at the data link layer on an Ethernet network? (Choose 3)
Physical address
Network address
Hierarchical address
MAC address
Burned-in address
Which statements about topologies are true? (Choose 2)
Ring, star, bus and mesh are types of physical topology
The logical topology is concerned with the way frames are passed from one
node to another
The physical topology must be the same as the logical topology
An Ethernet network always has a physical bus topology
The logical topology is the arrangement of the cables
Which would be the most useful to you if you wanted to check where the network
cables run in a building?
A knowledge of the logical topology
A knowledge of the physical topology
A knowledge of the IP addressing system used
A knowledge of the media access control method
Why is there more than one data link layer protocol in common use?
There is a lack of standardisation and widespread use of proprietary protocols.
Certain media and environments need more complex control mechanisms than
others to ensure delivery of data.
Each network layer protocol needs a different data link layer protocol.
LANs need a non-deterministic protocol and WANs need a deterministic
protocol.
