Chapter 5: Ethernet – Flashcards
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Which destination address is used in an ARP request frame?
a) FFFF.FFFF.FFFF
b) 255.255.255.255
c) 0.0.0.0
d) 01-00-5E-00-AA-23
answer
a) FFFF.FFFF.FFFF
The purpose of an ARP request is to find the MAC address of the destination host on an Ethernet LAN. The ARP process sends a Layer 2 broadcast to all devices on the Ethernet LAN. The frame contains the IP address of the destination and the broadcast MAC address, FFFF.FFFF.FFFF.
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Is this a characteristic of cut-through or store-and-forward?
always stores the entire frame
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store-and-forward
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Is this a characteristic of cut-through or store-and-forward?
checks the CRC before forwarding
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store-and-forward
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Is this a characteristic of cut-through or store-and-forward?
checks the frame length before forwarding
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store-and-forward
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Is this a characteristic of cut-through or store-and-forward?
does not forward broadcasts
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All forwarding methods require a Layer 2 switch to forward broadcast frames.
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Is this a characteristic of cut-through or store-and-forward?
has low latency
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cut-through
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Is this a characteristic of cut-through or store-and-forward?
may forward runt frames
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cut-through
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Is this a characteristic of cut-through or store-and-forward?
begins forwarding when the destination address is received
answer
cut-through
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The ARP table in a switch maps which two types of address together?
a) Layer 4 address to a Layer 2 address
b) Layer 2 address to a Layer 4 address
c) Layer 3 address to a Layer 2 address
d) Layer 3 address to a Layer 4 address
answer
c) Layer 3 address to a Layer 2 address
question
Which two statements describe features or functions of the logical link control sublayer in Ethernet standards? (Choose two.)
a) The LLC sublayer is responsible for the placement and retrieval of frames on and off the media.
b) The data link layer uses LLC to communicate with the upper layers of the protocol suite.
c) Logical link control is implemented in software.
d) Logical link control is specified in the IEEE 802.3 standard.
e) The LLC sublayer adds a header and a trailer to the data.
answer
b) The data link layer uses LLC to communicate with the upper layers of the protocol suite.
c) Logical link control is implemented in software.
question
Fill in the blank:
ARP______________is a technique that is used to send fake ARP messages to other hosts in the LAN. The aim is to associate IP addresses to the wrong MAC addresses.
answer
spoofing
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What happens to runt frames received by a Cisco Ethernet switch?
a) The frame is dropped.
b) The frame is returned to the originating network device.
c) The frame is broadcast to all other devices on the same network.
d) The frame is sent to the default gateway.
answer
a) The frame is dropped.
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What are the two sizes (minimum and maximum) of an Ethernet frame? (Choose two.)
a) 1024 bytes
b) 128 bytes
c) 64 bytes
d) 56 bytes
e) 1518 bytes
answer
c) 64 bytes
e) 1518 bytes
question
What is auto-MDIX?
a) a feature that detects Ethernet cable typ?e
b) a type of Cisco switch
c) a type of port on a Cisco switch
d) an Ethernet connector type
answer
a) a feature that detects Ethernet cable typ?e
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Fill in the blank.
On a Cisco switch,_____________________________________
memory buffering is used to buffer frames in queues linked to specific incoming and outgoing ports.?
answer
port-based
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Which statement describes the treatment of ARP requests on the local link?
a) They are dropped by all switches on the local network.
b) They must be forwarded by all routers on the local network.
c) They are received and processed only by the target device.
d) They are received and processed by every device on the local network.
answer
d) They are received and processed by every device on the local network.
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What statement describes a characteristic of MAC addresses?
a) They must be globally unique.
b) They have a 32-bit binary value.
c) They are added as part of a Layer 3 PDU.
d) They are only routable within the private network.
answer
They must be globally unique.
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True or False?
When a device is sending data to another device on a remote network, the Ethernet frame is sent to the MAC address of the default gateway.
answer
True
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What are two potential network problems that can result from ARP operation? (Choose two.)
a) Multiple ARP replies result in the switch MAC address table containing entries that match the MAC addresses of hosts that are connected to the relevant switch port.
b) Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent of intercepting network traffic.
c) On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays.
d) Manually configuring static ARP associations could facilitate ARP poisoning or MAC address spoofing.
e) Large numbers of ARP request broadcasts could cause the host MAC address table to overflow and prevent the host from communicating on the network.
answer
b & c
Large numbers of ARP broadcast messages could cause momentary data communications delays. Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent to intercept network traffic. ARP requests and replies cause entries to be made into the ARP table, not the MAC address table. ARP table overflows are very unlikely. Manually configuring static ARP associations is a way to prevent, not facilitate, ARP poisoning and MAC address spoofing. Multiple ARP replies resulting in the switch MAC address table containing entries that match the MAC addresses of connected nodes and are associated with the relevant switch port are required for normal switch frame forwarding operations. It is not an ARP caused network problem.
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Fill in the blank.
A collision fragment, also known as a _______frame, is a frame of fewer than 64 bytes in length.
answer
runt
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Which statement is true about MAC addresses?
a) MAC addresses are implemented by software.
b) The first three bytes are used by the vendor assigned OUI.
c) A NIC only needs a MAC address if connected to a WAN.
d) The ISO is responsible for MAC addresses regulations.
answer
b) The first three bytes are used by the vendor assigned OUI.
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What addressing information is recorded by a switch to build its MAC address table?
a) the source Layer 2 address of incoming frames
b) the source Layer 3 address of outgoing packets
c) the destination Layer 2 address of outgoing frames
d) the destination Layer 3 address of incoming packets
answer
a) the source Layer 2 address of incoming frames
question
What statement describes Ethernet?
a) It connects multiple sites such as routers located in different countries.
b) It defines a standard model used to describe how networking works.
c) It is the required Layer 1 and 2 standard for Internet communication.
d) It defines the most common LAN type in the world.
answer
d) It defines the most common LAN type in the world.
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Which switching method uses the CRC value in a frame?
a) fragment-free
b) fast-forward
c) store-and-forward
d) cut-through
answer
c) store-and-forward
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When a network device wants to communicate with another device on the same network, it sends a ____________ ____ _________. The request will contain the IP address the destination device.
answer
broadcast ARP request.
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The destination device of a broadcast ARP request containing the IP in the request, sends an ________ ______with its MAC address.
answer
ARP reply
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Ethernet operates in the what layer or layers?
answer
data link layer and the physical layer.
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The Ethernet LLC sublayer handles the communication between?
answer
The upper layers and the lower layers. This is typically between the networking software and the device hardware.
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LLC is implemented in __________ , and its implementation is independent of the __________.
answer
software, hardware
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Frame delimiting, Addressing, and Error detection are all example so of?
answer
Data Encapsulation
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Control of frame placement on and off the media and
Media recovery are both examples of?
answer
Media Access Control
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The Ethernet MAC sublayer has two primary responsibilities what are they?
answer
Data encapsulation
Media access control
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The data encapsulation process includes frame assembly _________ transmission over the media.
answer
transmission
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Frame dis-assembly happens at the host or source?.
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Host
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The framing process provides important delimiters that are used to identify a group of bits that make up a frame. These delimiting bits provide synchronization between the transmitting and receiving nodes.
This is known as what term in data data encapsulation?
answer
Frame delimiting
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The encapsulation process contains the Layer 3 PDU and also provides for data link layer addressing.
This is known as what term in data encapsulation?
answer
Addressing
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Each frame contains a trailer used to detect any errors in transmissions.
This is known as what term in data encapsulation?
answer
Error detection
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What datalink sublayer is responsible for the placement of frames on the media and the removal of frames from the media. It controls access to the media. This sublayer communicates directly with the physical layer.
answer
Media access control
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A contention-based method means what?
answer
Any device can try to transmit data across the shared medium whenever it has data to send.
