1.
Where does the MAC address originate?
Correct Answer
C. Burned into ROM on the NIC card
Explanation
The MAC address is a unique identifier assigned to each network interface card (NIC) by the manufacturer. It is permanently stored in read-only memory (ROM) on the NIC card, which means it cannot be modified or changed. This allows the NIC card to be identified on the network regardless of its location or connection. The MAC address is not originated from the DHCP server database, configured by the administrator, part of the network configuration on the computer, or included in the creation of the processor chip.
2.
Which of the following are specified by IEEE standards as sublayers of the OSI data link layer? (Choose two)
Correct Answer(s)
A. Logical Link Control
C. Media Access Control
Explanation
The IEEE standards specify Logical Link Control and Media Access Control as the sublayers of the OSI data link layer. The Logical Link Control sublayer is responsible for flow control, error control, and framing. It manages the logical link between two devices and ensures reliable data transfer. The Media Access Control sublayer is responsible for controlling access to the physical transmission medium. It manages the access rights of devices to the shared medium, resolves conflicts, and handles addressing.
3.
Why do hosts on an Ethernet segment that experience a collision use a random delay before attempting to transmit a frame?
Correct Answer
C. A random delay helps prevent the stations from experiencing another collision during the transmission
Explanation
A random delay helps prevent the stations from experiencing another collision during the transmission. This is because when multiple hosts on an Ethernet segment attempt to transmit at the same time, a collision occurs. By introducing a random delay before retransmitting, the likelihood of multiple hosts choosing the same time to transmit again is reduced. This helps to prevent another collision, allowing for more efficient transmission of data on the network.
4.
A technician wants to increase the available bandwidth for the workstation by allowing the switch and the NIC on the workstation to transmit and receive simultaneously. What will permit this?
Correct Answer
B. Full-duplex
Explanation
Full-duplex communication allows both the switch and the NIC on the workstation to transmit and receive data simultaneously. This means that the workstation can send and receive data at the same time without any collisions, increasing the available bandwidth. CSMA/CD is a collision detection method used in half-duplex communication, where devices take turns transmitting and receiving. FastEthernet is a type of Ethernet technology that provides higher data transfer rates. A crossover cable is used to directly connect similar devices, such as two computers, without the need for a switch.
5.
When a collision occurs in a network using CSMA/CD, how do hosts with data to transmit respond after the backoff period has expired?
Correct Answer
A. The hosts return to a listen-before-transmit mode.
Explanation
After the backoff period has expired, the hosts with data to transmit in a network using CSMA/CD return to a listen-before-transmit mode. This means that they will listen for any ongoing transmissions on the network before attempting to transmit their own data. This helps to avoid further collisions and ensures that the network operates efficiently and without interference.
6.
What are three functions of a NIC in a PC? (Choose three)
Correct Answer(s)
A. A NIC connects the PC to the network media.
B. A NIC detects collisions on the Ethernet segment.
D. A NIC passes the contents of selected frames to the upper OSI layers.
Explanation
A NIC connects the PC to the network media, allowing the PC to send and receive data over the network. It also detects collisions on the Ethernet segment, which helps in managing network congestion and ensuring efficient data transmission. Additionally, a NIC passes the contents of selected frames to the upper OSI layers, allowing the PC to process and interpret the received data.
7.
Which characteristics describe carrier sense multiple access collision detect (CSMA/CD)? (Choose three)
Correct Answer(s)
B. Nondeterministic
D. Collision environment
E. First-come, first-served approach
Explanation
CSMA/CD is a protocol used in Ethernet networks to avoid collisions. It is nondeterministic because the time at which a station can transmit data is not predetermined. It operates in a collision environment where multiple stations can transmit simultaneously, causing collisions. CSMA/CD also uses a first-come, first-served approach, where the station that senses the channel first gets to transmit its data.
8.
Which two devices can provide full-duplex Ethernet connections? (Choose two)
Correct Answer(s)
D. NIC
E. Layer 2 switch
Explanation
A NIC (Network Interface Card) and a Layer 2 switch can both provide full-duplex Ethernet connections. A NIC is a hardware component that allows a device to connect to a network, and it can support full-duplex communication, which means it can send and receive data simultaneously. A Layer 2 switch is a network device that operates at the data link layer of the OSI model and can also support full-duplex communication. It can receive and forward data simultaneously on different ports, allowing for efficient and high-speed communication between devices on a network.
9.
In which two layers of the OSI model does Ethernet function? (Choose two)
Correct Answer(s)
D. Data link
E. pHysical
Explanation
Ethernet functions in the data link layer and the physical layer of the OSI model. The data link layer is responsible for the reliable transfer of data between two nodes on the same network, while the physical layer deals with the actual transmission of the data over the physical medium, such as cables or wireless signals. Ethernet protocols define the rules and standards for how data is transmitted and received at these layers, making Ethernet a key technology for local area networks (LANs).
10.
All hosts are in listen mode, Host 1 and Host 4 both transmit data at the same time. How do the hosts respond on the network? (Choose two)
Correct Answer(s)
C. After the end of the jam signal, a backoff algorithm is invoked.
E. If a host has data to transmit after the backoff period of that host, the host checks to determine if the line is idle, before transmitting.
Explanation
When Host 1 and Host 4 both transmit data at the same time, a collision may occur. After the collision, a jam signal is sent to notify all hosts on the network. Then, a backoff algorithm is invoked, which assigns a random backoff value to each host involved in the collision. Host 1 and Host 4 may be assigned shorter backoff values to give them priority to access the media. Once the backoff period of a host is over, the host checks if the line is idle before transmitting its data to avoid further collisions.
11.
Host A is communicating with host F. What happens to a frame sent from host A to host F as it travels over the Ethernet segments.
Correct Answer
B. The frame format remains the same across each Ethernet segment.
Explanation
The frame format remains the same across each Ethernet segment. This means that as the frame travels from host A to host F, the structure and format of the frame remains unchanged. The frame does not undergo any modifications in terms of its format as it passes through switches or as the media speed or material changes. The frame is simply forwarded from one segment to another without any alterations to its format.
12.
How many hexadecimal digits are in a MAC address?
Correct Answer
C. 12
Explanation
A MAC address is a unique identifier assigned to network interfaces for communications on a network. It consists of 12 hexadecimal digits, which are a combination of numbers (0-9) and letters (A-F). Each digit represents 4 bits, so a MAC address contains a total of 48 bits. Therefore, the correct answer is 12.
13.
At what layer of the OSI model does a MAC address reside?
Correct Answer
B. 2
Explanation
A MAC address, also known as a Media Access Control address, is a unique identifier assigned to a network interface card (NIC) of a device. It is used to identify devices on a local network. The MAC address operates at the data link layer, which is the second layer of the OSI model. This layer is responsible for the reliable transmission of data between directly connected network devices. Therefore, the correct answer is 2.
14.
A router has an Ethernet, Token Ring, serial, and an ISDN interface. Which interfaces will have a MAC address?
Correct Answer
B. Ethernet and Token Ring interfaces
Explanation
Ethernet and Token Ring interfaces will have a MAC address. A MAC address is a unique identifier assigned to each network interface card (NIC) in a device. Ethernet and Token Ring are both types of network protocols that use MAC addresses for communication. Serial and ISDN interfaces, on the other hand, are not Ethernet-based protocols and therefore do not require MAC addresses for communication.
15.
In an Ethernet LAN, how does the NIC know when it can transmit data?
Correct Answer
D. An Ethernet NIC transmits data after listening for the absence of a signal on the media.
Explanation
The correct answer is that an Ethernet NIC transmits data after listening for the absence of a signal on the media. This is known as Carrier Sense Multiple Access with Collision Detection (CSMA/CD). The NIC listens for any ongoing transmission on the network. If it detects that the media is idle, meaning there is no signal present, it transmits its data. This helps to avoid collisions with other devices that may be transmitting at the same time. By waiting for the absence of a signal, the NIC can ensure that it has a clear channel to transmit its data without causing interference.
16.
The small office network shown in the exhibit consists of four computers connected through a hub. Which configuration would cause collisions and errors on the network?
Correct Answer
D. Administratively configured full duplex
Explanation
Administratively configured full duplex would cause collisions and errors on the network. In full duplex mode, both devices can transmit and receive data simultaneously without any collisions. However, if one device is configured for full duplex and the other device is configured for half duplex or autonegotiation, collisions can occur. This is because the device configured for full duplex will be transmitting and receiving data simultaneously, while the other device will be following the half duplex rules, resulting in collisions and errors on the network.