Questions and Answers
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?
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Which three factors could influence the differences in throughput in a network? (Choose three.)
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What are two characteristics of fiber-optic cable? (Choose two.)
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What is a primary role of the Physical layer in transmitting data on the network?
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With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?
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What type of cabling is shown in the graphic?
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In addition to the cable length, what two factors could interfere with the communication carried over UTP cables? (Choose two.)
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What two devices commonly affect wireless networks? (Choose two.)
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Which two statements describe the services provided by the data link layer? (Choose two.)
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What is the function of the CRC value that is found in the FCS field of a frame?
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What is contained in the trailer of a data-link frame?
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Which statement describes a characteristic of the frame header fields of the data link layer?
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Which topology provides high availability and connects some, but not all, remote sites?
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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? (Choose two.)
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Which media communication type does not require media arbitration in the data link layer?
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Which statement describes an extended star topology?
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What is a characteristic of the LLC sublayer?
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What are three ways that media access control is used in networking? (Choose three.)
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During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?
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What three items are contained in an Ethernet header and trailer? (Choose three.)
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What type of communication rule would best describe CSMA/CD?
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Which three basic parts are common to all frame types supported by the data link layer? (Choose three.)
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Is it true that all network devices must listen before transmitting?
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What is the destination MAC address of the Ethernet frame as it leaves the web server if the final destination is PC1?
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A Layer 2 switch is used to switch incoming frames from a 1000BASE-T port to a port connected to a 100Base-T network. Which method of memory buffering would work best for this task?
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What are two examples of the cut-through switching method? (Choose two.)
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Which frame forwarding method receives the entire frame and performs a CRC check to detect errors before forwarding the frame?
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What is the purpose of the FCS field in a frame?
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Which switching method has the lowest level of latency?
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When connecting two switches using a straight-through cable, which three statements are correct about the final result of the connection? (Choose three.)
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Which advantage does the store-and-forward switching method have compared with the cut-through switching method?
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When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check?
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Which switching method uses the CRC value in a frame?
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What are two actions performed by a Cisco switch? (Choose two.)
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Which two statements describe features or functions of the logical link control (LLC) sublayer in Ethernet standards? (Choose two.)
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What is the auto-MDIX feature?
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What is one advantage of using the cut-through switching method instead of the store-and-forward switching method?
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Which is a multicast MAC address?
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What is wrong with the displayed termination?
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Which types of UTP cables can be used to connect the devices? (Select the correct options.)
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Which port does Switch0 use to send frames to the host with the IPv4 address 10.1.1.5?
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What does the term 'attenuation' mean in data communication?
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What makes fiber preferable to copper cabling for interconnecting buildings? (Choose three.)
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What OSI physical layer term describes the process by which one wave modifies another wave?
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What OSI physical layer term describes the capacity at which a medium can carry data?
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What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time?
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What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?
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What OSI physical layer term describes the measure of usable data transferred over a given period of time?
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What OSI physical layer term describes the physical medium which uses electrical pulses?
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What OSI physical layer term describes the physical medium that uses the propagation of light?
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What OSI physical layer term describes the physical medium for microwave transmissions?
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Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)
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Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.)
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What action will occur if a switch receives a frame with the destination MAC address FF:FF:FF:FF:FF:FF?
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What action will occur if a host receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF?
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What action will occur if a switch receives a frame and does not have the source MAC address in the MAC table?
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Which type of UTP cable is used to connect a PC to a switch port?
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Study Notes
OSI Physical Layer
- Responsible for transmitting bits across local media.
- Modulation: process where one wave modifies another wave.
- Bandwidth: capacity of a medium to carry data.
- Throughput: measure of bit transfer over a medium in a given timeframe.
- Latency: time taken for data to travel from one point to another.
- Goodput: measure of usable data transferred over a specific period.
- Copper cable: uses electrical pulses as the physical medium.
- Fiber-optic cable: uses light propagation as the physical medium.
- Microwave transmissions utilize air as the physical medium.
Fiber Optic and Copper Cables
- Fiber optic connections typically use two strands for full-duplex connectivity.
- Fiber-optic cables are immune to electromagnetic interference (EMI) and radio frequency interference (RFI) but are more costly than unshielded twisted pair (UTP) cables.
- Advantages of fiber: longer distances, less EMI/RFI susceptibility, higher bandwidth potential.
Crosstalk and Interference
- Crosstalk occurs due to distortion from adjacent wire signals, often mitigated by twisting wire pairs.
- UTP communication can be disrupted by crosstalk and electromagnetic interference, affecting data transmission quality.
Data Link Layer Functions
- Manages frame access to network media and packages Layer 3 protocol data units (PDUs) into frame format.
- Frame Check Sequence (FCS) in the trailer is used to detect errors in frame transmission.
- Variables in header fields can change depending on the protocol used.
Network Topologies
- Partial mesh topology connects some remote sites to a headquarters while providing high availability.
- In an extended star topology, end devices connect to a central intermediate device, which connects to other such devices.
Ethernet Frame and Switching Methods
- Ethernet examines the Frame Check Sequence and minimum frame size to determine frame validity.
- Full-duplex communication does not require media arbitration, allowing simultaneous data transmission.
- Store-and-forward switching checks the entire frame and performs a CRC to verify integrity.
- Cut-through switching, including fast-forward and fragment-free methods, minimizes latency.
- Shared memory buffering is ideal for switching between differing network speeds (e.g., between 1000BASE-T and 100BASE-T).
MAC Sublayer Actions
- The MAC sublayer manages the Network Interface Card (NIC), placing a trailer in frames for error detection.
- The Logical Link Control (LLC) sublayer allows multiple Layer 3 protocols to utilize the same network media by identifying the appropriate protocol in the frame.
Switch Operations
- When a frame’s destination MAC is broadcasted (FF:FF:FF:FF:FF:FF), the switch forwards it to all ports except the one it was received on.
- Multicast frames (e.g., 01:00:5E:00:00:D9) also follow the same forwarding principle.
- If a switch receives a frame from a known source MAC, it refreshes that entry in its MAC address table.
UTP Cable Types
- Straight-through cables are required to connect PCs to switch ports.
- Various cable types, including rollover, straight-through, and crossover, serve different connection purposes, particularly in switching configurations.
Key Factors Affecting Network Throughput
- Throughput can be influenced by current network traffic, types of traffic, and the latency introduced by devices the data crosses.
Error Checking in Ethernet
- A frame's trailer contains error detection information crucial for maintaining data integrity during transmission.
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Description
Test your knowledge on Ethernet concepts from CCNA 1 v7 with this flashcard quiz. Focused on the OSI model and fiber optic technology, this quiz includes key definitions and principles of networking. Prepare effectively for your CCNA certification exam by mastering these concepts.