Module 4-7 Flashcards
What is the purpose of the OSI physical layer?
Transmitting bits across the local media
Why are two strands of fiber used for a single fiber optic connection?
They allow for full-duplex connectivity.
Which characteristic describes crosstalk?
The distortion of the transmitted messages from signals carried in adjacent wires
Which procedure is used to reduce the effect of crosstalk in copper cables?
twisting opposing circuit wire pairs together
What are two characteristics of fiber-optic cable?
It is more expensive than UTP cabling is.
It is not affected by EMI or RFI.
What is a primary role of the Physical layer in transmitting data on the network?
create the signals that represent the bits in each frame on to the media
Which layer accepts a complete frame from the data link layer and encodes it as a series of signals that are transmitted to the local media?
OSI Physical layer
With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?
the magnetic field around the adjacent pairs of wire
Which three basic parts are common to all frame types supported by the data link layer?
Trailer
Header
Data
What utilized CSMA/CD?
Ethernet
Protocols that define the rules for access to different media…
Data Link Layer
Provides placement of data frames onto the media.
Media Access Control
Layer that packages various Layer 3 PDUs into a frame that is compatible with the network interface.
Data Link Layer.
Layer that manages the access of frames to the network media.
Data Link Layer.
Describe extended star topology.
End devices connect to a central intermediate device, which in turn connects to other central intermediate devices.
Which two fields or features does Ethernet examine to determine if a received frame is passed to the data link layer or discarded by the NIC?
Frame Check Sequence.
Minimum Frame Size
What places information in the frame allowing multiple layer 3 protocols to use the same network interface and media?
LLC Sublayer.
All network devices must listen before transmitting.. This describes what?
CSMA/CD Access Method.
What three items are contained in an Ethernet header and trailer?
Source MAC Address.
Destination MAC Address.
Error-Checking Information.
Do frame header fields of the data link layer vary depending on protocols, or do they stay the same?
They vary depending on protocols.
What action will occur if a host receives a frame with a destination MAC address it does not recognize?
The host will discard the frame.
What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?
Latency.
What is the purpose of the FCS field in a frame?
to determine if errors occurred in the transmission and reception
What is the auto-MDIX feature on a switch?
the automatic configuration of an interface for a straight-through or a crossover Ethernet cable connection.
Which advantage does the store-and-forward switching method have compared with the cut-through switching method?
Frame Error Checking.
Which switching method has the lowest level of latency?
Fast-Forward.
Fast-Forward Switching and Fragment-free Switching are examples of what type of switching method?
Cut-through switching.
Which switching method uses the CRC value in a frame?
store-and-forward
When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check?
The cyclical redundancy check (CRC) in the trailer.
What is the auto-MDIX feature?
It enables a device to automatically configure an interface to use a straight-through or a crossover cable.
A network administrator is measuring the transfer of bits across the company backbone for a mission critical financial application. The administrator notices that the network throughput appears lower than the bandwidth expected. Which three factors could influence the differences in throughput?
The amount of traffic that is currently crossing the network.
The type of traffic that is crossing the network.
The latency that is created by the number of network devices that the data is crossing.
Which two devices commonly affect wireless networks?
Cordless Phones.
Microwaves.
In addition to the cable length, what two factors could interfere with the communication carried over UTP cables?
Cross-talk
Electromagnetic interference.
With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?
The magnetic field around the adjacent pairs of wire.
What does the term “attenuation” mean in data communication?
loss of signal strength as distance increases
What makes fiber preferable to copper cabling for interconnecting buildings?
limited susceptibility to EMI/RFI
greater bandwidth potential
greater distances per cable run
What are two characteristics of fiber-optic cable?
Not affected by EMI or RFI.
It is more expensive than UTP cabling.
What is a primary role of the Physical layer in transmitting data on the network?
To create the signals that represent the bits in each frame on the media.
2 sublayers of the Data Link Layer
Logical Link Control (LLC)
Media Access Control (MAC)
What is the function of the CRC value that is found in the FCS field of a frame?
To verify the integrity of the received frame.
What is contained in the trailer of a data-link frame?
Error Detection
A network team is comparing physical WAN topologies for connecting remote sites to a headquarters building. Which topology provides high availability and connects some, but not all, remote sites?
Partial Mesh
hich two fields or features does Ethernet examine to determine if a received frame is passed to the data link layer or discarded by the NIC?
Frame Check Sequence
Minimum Frame Size
This sublayer places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.
Logical Link Control (LLC)
During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?
The physical address is added.
What is the purpose of the FCS field in a frame?
To determine if errors occurred in the transmission and reception
Logical Link Control is implemented in….
software
What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time?
Through-put
What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?
Latency
What OSI physical layer term describes the measure of usable data transferred over a given period of time?
Goodput
What OSI physical layer term describes the physical medium which uses electrical pulses?
Copper Cable
What OSI physical layer term describes the physical medium for microwave transmissions?
Air
Which sublayer Implements a trailer to detect transmission errors.
MAC sublayer
Which sublayer Controls the NIC responsible for sending and receiving data on the physical medium.
MAC sublayer
Which sublayer Enables IPv4 and IPv6 to utilize the same network interface and media.
LLC sublayer
Which sublayer Places information in the frame that identifies which network layer protocol is being used for the frame.
LLC sublayer
What action will occur if a switch receives a frame and does have the source MAC address in the MAC table?
The switch refreshes the timer on that entry.
What action will occur if a switch receives a frame and does have the source MAC address in the MAC table?
The switch refreshes the timer on that entry.
What action will occur if a host receives a frame with a destination MAC address it does not recognize?
The host will discard the frame.
