CCNA 4-7
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
What characteristic describes crosstalk?
the distortion of the transmitted messages from signals carried in adjacent wires
Refer to the exhibit. q 30
30
In addition to the cable length, what two factors could interfere with the communication carried over UTP cables?
crosstalk electromagnetic interference
Which statement describes an extended star topology?
end devices connect to a central intermediate device, which in turn connects to other central intermediate devices
What is contained in the trailer of a data-link frame?
error detection
Which switching method has the lowest level of latency?
fast-forward
What are two examples of the cut-through switching method?
fast-forward switching fragment-free switching
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
Which advantage does the store-and-forward switching method have compared with the cut-through switching method?
frame error checking
Which media communication type does not require media arbitration in the data link layer?
full-duplex
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?
shared memory buffering
Which switching method uses the CRC value in a frame?
store-and-forward
Which frame forwarding method receives the entire frame and performs a CRC check to detect errors before forwarding the frame?
store-and-forward switching
What are three ways that media access control is used in networking?
1.) Ethernet utilizes CSMA/CD 2.) Media access control provides placement of data frames onto the media 3.) Data link layer protocols define the rules for access to different media.
Which two statements describe features or functions of the logical link control sublayer in Ethernet standards?
1.) Logical link control is implemented in software 2.) The data link layer uses LLC to communicate with the upper layers of the protocol suite.
What three items are contained in an Ethernet header and trailer?
1.) source MAC address 2.) destination MAC address 3.) error-checking information
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?
1.) the amount of traffic that is currently crossing the network 2.) the type of traffic that is crossing the network 3.) the latency that is created by the number of network devices that the data is crossing
A network administrator is connecting two modern switches using a straight-through cables. The switches are new and have never been configured. Which three statements are correct about the final result of the connection?
1.)The link between the switches will work at the fastest speed that is supported by both switches. 2.)The link between switches will work as full-duplex. 3.)The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable.
Which three basic parts are common to all frame types supported by the data link layer?
1.)header 2.)data 3.)trailer
What are two actions performed by a Cisco switch?
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
Which statement is true about the CSMA/CD access method that is used in Ethernet?
All network devices must listen before transmitting.
When the store-and-forward method of switching is is use, what part of the Ethernet frame is used to perform an error check?
CRC in the trailer
What type of communication rule would best describe CSMA/CD?
access method
Fiber optic is used in/for
backbone cabling in an enterprise and long-haul networks
Which two devices commonly affect wireless networks?
cordless phones microwaves
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
What are two characteristics of fiber-optic cable?
it is not affected by EMI or RFI it is more expensive than UTP cabling is
Which two statements describe the services provided by the data link layer?
it manages the access of frames to the network media it packages various Layer 3 PDUs into a frame format that is compatible with the network interface
What is characteristic of the LLC sublayer?
it places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.
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
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
During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?
the physical address is added
Why are two strands of fiber used for single fiber optic connection?
they allow for full-duplex connectivity
Which statement describes a characteristic of the frame header fields of the data link layer?
they vary depending on protocols
What is the purpose of the FCS field in a frame?
to determine if errors occured in the transmission and reception
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 the purpose of the OSI physical layer?
transmitting bits across the local media
Which procedure is used to reduce the effect of crosstalk in copper cables?
twisting opposing circuit wire pairs together