CNA 101 - Modules 4-7: Ethernet Concepts - Assessment
Shared Memory Buffering
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?
1. Controls the NIC responsible for sending and receiving data on the physical medium. 2. It provides a mechanism to allow multiple devices to communicate over a shared medium.
Which two functions are performed at the MAC sublayer of the OSI data link layer?
1. Implements a trailer to detect transmission errors. 2. Provides synchronization between source and target nodes.
Which two functions are performed at the MAC sublayer of the OSI data link layer?
**Logical link control is implemented in software. **The data link layer uses LLC to communicate with the upper layers of the protocol suite. The LLC sublayer is responsible for the placement and retrieval of frames on and off the media. The LLC sublayer adds a header and a trailer to the data. Logical link control is specified in the IEEE 802.3 standard.
Which two statements describe features or functions of the logical link control sublayer in Ethernet standards?
1. It packages various Layer 3 PDUs into a frame format that is compatible with the network interface. 2. It manages the access of frames to the network media.
Which two statements describe the services provided by the data link layer?
the magnetic field around the adjacent pairs of wire
With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?
1. The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable. 2. The link between the switches will work at the fastest speed that is supported by switches. 3. The link between switches will work as full-duplex.
A network administrator is connecting two modern switches using a straight-through cable. The switches are new and have never been configured. Which three statements are correct about the final result of the connection?
##the amount of traffic that is currently crossing the network the sophistication of the encapsulation method applied to the data ##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 the bandwidth of the WAN connection to the Internet the reliability of the gigabit Ethernet infrastructure of the backbone
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?
Partial Mesh
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?
An IP address is added. **The physical address is added. The process port number is added. The logical address is added.
During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?
1. Crosstalk 2. Electromagnetic interference
In addition to the cable length, what two factors could interfere with the communication carried over UTP cables?
00-60-2F-3A-07-BB **00-60-2F-3A-07-CC 00-60-2F-3A-07-AA 00-60-2F-3A-07-DD
Refer to the exhibit. What is the destination MAC address of the Ethernet frame as it leaves the web server if the final destination is PC1?
UTP
Refer to the graphic. What type of cabling is shown?
A. 1 - rollover, 2 - straight-through, 3 - crossover
The PC is connected to the console port of the switch. All the other connections are made through FastEthernet links. Which types of UTP cables can be used to connect the devices?
**Integrates various physical technologies. Adds Layer 2 control information to network protocol data. Enables IPv4 and IPv6 to utilize the same network interface and media. **Provides synchronization between source and target nodes. Communicates between the networking software at the upper layers and the device hardware at the lower layers.
Two functions are performed at the MAC sublayer of the OSI data link layer.
throughput goodput **bandwidth latency
What OSI physical layer term describes the capacity at which a medium can carry data?
Throughput
What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time?
**The host replies to the switch with its own IP address. The host will process the frame. The host forwards the frame to all other hosts. The host returns the frame to the switch.
What action will occur if a host receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF?
**The switch refreshes the timer on that entry. The switch forwards the frame to the associated port. The switch sends the frame to a connected router because the destination MAC address is not local. The switch adds it to its MAC address table associated with the port number.
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. **The switch forwards the frame to the associated port. The switch sends the frame to a connected router because the destination MAC address is not local. The switch adds it to its MAC address table associated with the port number.
What action will occur if a switch receives a frame and does have the source MAC address in the MAC table?
The switch forwards it out all ports except the ingress port.
What action will occur if a switch receives a frame with the destination MAC address FF:FF:FF:FF:FF:FF?
1. Data link layer protocols define the rules for access to 2. Ethernet utilizes CSMA/CD. 3. Media access control provides placement of data frames onto the media.
What are three ways that media access control is used in networking?
1. Using the source MAC addresses of frames to build and maintain a MAC address table. 2. Utilizing the MAC address table to forward frames via the destination MAC address.
What are two actions performed by a Cisco switch?
Each pair of cables is wrapped in metallic foil. It typically contains 4 pairs of fiber-optic wires. It combines the technique of cancellation, shielding, and twisting to protect data. **It is more expensive than UTP cabling is. **It is not affected by EMI or RFI.
What are two characteristics of fiber-optic cable?
1. Fast-forwarding Switching 2. Fragment-Free Switching
What are two examples of the cut-through switching method?
Loss of signal strength as distance increases.
What does the term "attenuation" mean in data communication?
It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.
What is a characteristic of the LLC sublayer?
Error Detection
What is contained in the trailer of a data-link frame?
It has a lower latency appropriate for high-performance computing applications.
What is one advantage of using the cut-through switching method instead of the store-and-forward switching method?
It enables a device to automatically configure an interface to use a straight-through or a crossover cable.
What is the auto-MDIX feature?
to verify the physical address in the frame to verify the logical address in the frame to compute the checksum header for the data field in the frame **to verify the integrity of the received frame
What is the function of the CRC value that is found in the FCS field of a frame?
To determine if errors occurred in the transmission and reception.
What is the purpose of the FCS field in a frame?
The untwisted length of each wire is too long.
What is wrong with the displayed termination?
1. Greater Bandwidth Potential 2. Greater Distances per cable run 3. Limited susceptibility to EMI/RFI
What makes fiber preferable to copper cabling for interconnecting buildings?
destination IP address source IP address **source MAC address **destination MAC address **error-checking information
What three items are contained in an Ethernet header and trailer? (Choose three.)
Access Method
What type of communication rule would best describe CSMA/CD?
flow control message encoding **access method message encapsulation
What type of communication rule would best describe CSMA/CD?
CRC in the trailer
When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check?
frame error checking
Which advantage does the store-and-forward switching method have compared with the cut-through switching method?
cut-through switching **store-and-forward switching fast-forward switching fragment-free switching
Which frame forwarding method receives the entire frame and performs a CRC check to detect errors before forwarding the frame?
FF-FF-FF-FF-FF-FF **01-00-5E-00-00-03 00-26-0F-4B-00-3E 5C-26-0A-4B-19-3E
Which is a multicast MAC address?
Full-Duplex
Which media communication type does not require media arbitration in the data link layer?
They all include the flow control and logical connection fields. Ethernet frame header fields contain Layer 3 source and destination addresses. **They vary depending on protocols. They include information on user applications.
Which statement describes a characteristic of the frame header fields of the data link layer?
End devices connect to a central intermediate device, which in turn connects to other central intermediate devices.
Which statement describes an extended star topology?
Devices involved in a collision get priority to transmit after the backoff period. **All network devices must listen before transmitting. When a device hears a carrier signal and transmits, a collision cannot occur. A jamming signal causes only devices that caused the collision to execute a backoff algorithm.
Which statement is true about the CSMA/CD access method that is used in Ethernet?
**fast-forward cut-through store-and-forward fragment-free
Which switching method has the lowest level of latency?
**store-and-forward fast-forward fragment-free cut-through
Which switching method uses the CRC value in a frame?
type field **trailer **header **data CRC value MTU size
Which three basic parts are common to all frame types supported by the data link layer?
Blu-ray players **microwaves **cordless phones external hard drives incandescent light bulbs home theaters
Which two devices commonly affect wireless networks?
1. Minimum Frame Size 2. Frame Check Sequence
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?