CCNA1 v7 - Modules 4-7
Which two functions are performed at the MAC sublayer of the OSI data link layer?
1. Controls the NIC responsible for sending and receiving data on the physical medium. 2. Implements a trailer to detect transmission errors. *There are 6 different versions of this question on the website with different answers, so just have the knowledge of what the MAC sublayer does*
Which two functions are performed at the LLC sublayer of the OSI data link layer?
1. Enables IPv4 and IPv6 to utilize the same network interface and media. 2. Places information in the frame that identifies which network layer protocol is being used for the frame
Which two functions are performed at the LLC sublayer of the OSI data link layer?
1. Enables IPv4 and IPv6 to utilize the same network interface and media. 2. Places information in the frame that identifies which network layer protocol is being used for the frame. *There are 4 different versions of this question on the website with different answers, so just have the knowledge of what the LLC sublayer does*
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.
In Ethernet standards, what are two features or functions of the logical link control sublayer?
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.
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
What OSI physical layer term describes the physical medium for microwave transmissions?
Air *This is a stupid question, but it was on the website*
What three items are contained in an Ethernet header and trailer? A) source IP address B) source MAC address C) destination IP address D) destination MAC address E) error-checking information
B, D, and E
What type of cable is shown?
Coaxial. Copper conductor and a layer of flexible plastic insulation surrounds the copper conductor.
Which types of UTP cables can be used to connect the devices in the following image? Note: The PC is connected to the console port of the switch. All the other connections are made through FastEthernet links.
Connection 1 - Rollover Connection 2 - Straight-through Connection 3 - Crossover
What OSI physical layer term describes the physical medium which uses electrical pulses?
Copper cable
Which two devices commonly affect wireless networks?
Cordless phones and 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
Which type of UTP cable is used to connect like devices?
Crossover (Switch-to-switch)
What OSI physical layer term describes the measure of usable data transferred over a given period of time?
Goodput
What makes fiber preferable to copper cabling for interconnecting buildings?
Greater distances per cable run, limited susceptibility to EMI/RFI, and greater bandwidth potential
What are some examples of Wireless media?
Guest access in a coffee shop, waiting rooms in a hospital, etc
What is one advantage of using the cut-through switching method instead of the store-and-forward switching method?
Has a lower latency appropriate for high-performance computing applications
Which three basic parts are common to all frame types supported by the data link layer?
Header, data, and trailer
What are some characteristics of Copper cables?
Horizontal cabling structure. Can be used for desktop PCs in an enterprise office
Name the two sub layers of the Data Link layer.
Logical Link Control (LLC) and Media Access Control (MAC)
What does the term "attenuation" mean in data communication?
Loss of signal strength as distance increases
What OSI physical layer term describes the process by which one wave modifies another wave?
Modulation
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
What type of cable is shown?
STP. Four pairs of wires, each wrapped in a foil shield, which are then wrapped in an overall metallic braid or foil.
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
Which type of UTP cable is used to connect different types of devices?
Straight-through (PC-to-Switch)
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 are some characteristics of Fiber optic cables?
The backbone cabling in an enterprise used for long-haul networks. Not affected by EMI/RFI. More expensive than UTP cabling.
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 action will occur if a host receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF?
The host will process the frame.
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 (Electromagnetic waves/Radio Frequencies)
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 action will occur if a switch receives a frame with the destination MAC address 01:00:5E:00:00:D9?
The switch forwards it out all ports except the ingress port.
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?
00-60-2F-3A-07-CC *Be able to look at a network and determine MAC addresses based on source and destination*
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 type of UTP cable is used to connect Cisco devices?
A rollover cable
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? (Choose three.) A) The link between the switches will work at the fastest speed that is supported by both switches. B) The link between switches will work as full-duplex. C) If both switches support different speeds, they will each work at their own fastest speed. D) The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable. E) The connection will not be possible unless the administrator changes the cable to a crossover cable. F) The duplex capability has to be manually configured because it cannot be negotiated.
A, B, and D
What type of communication rule would best describe CSMA/CD?
Access method
What OSI physical layer term describes the capacity at which a medium can carry data?
Bandwidth
Which statement is true about the CSMA/CD access method that is used in Ethernet? A) When a device hears a carrier signal and transmits, a collision cannot occur. B) A jamming signal causes only devices that caused the collision to execute a backoff algorithm. C) All network devices must listen before transmitting. D) Devices involved in a collision get priority to transmit after the backoff period.
C
Which is a multicast MAC address? A) FF-FF-FF-FF-FF-FF B) 5C-26-0A-4B-19-3E C) 01-00-5E-00-00-03 D) 00-26-0F-4B-00-3E
C - Multicast MAC addresses begin with the special value of 01-00-5E.
When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check?
CRC (Cyclic Redundancy Check) in the trailer
What is 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 and fragment-free switching
What type of cabling is shown?
Fiber, Flexible, extremely thin, transparent strand of glass surrounded by plastic insulation.
What OSI physical layer term describes the physical medium that uses the propagation of light?
Fiber-optic cable
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 (FCS) and 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
What are two statements that 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 a characteristic of the LLC sublayer?
It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.
What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?
Latency
What action will occur if a switch receives a frame with the destination MAC address FF:FF:FF:FF:FF:FF?
The switch forwards it out all ports except the ingress port.
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.
Refer to the exhibit. What is wrong with the displayed termination?
The untwisted length of each wire is too long (it was crimped on top of the bare wires).
Why are two strands of fiber used for a single fiber optic connection?
They allow for full-duplex connectivity.
What is a characteristic of the frame header fields of the data link layer?
They vary depending on protocols
What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time?
Throughput
What is the purpose of the FCS field in a frame?
To determine if errors occurred 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 type of cabling is shown?
UTP, Four pairs of color-coded wires that have been twisted together and then encased in a flexible plastic sheath.
Which characteristic describes crosstalk?
the distortion of the transmitted messages from signals carried in adjacent wires
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
