Online Exam: CCNA V4 Practice Quiz Questions!

The MAC (Media Access Control) sublayer of the data link layer prepares a signal to be transmitted at the physical layer. It is responsible for controlling access to the physical medium and ensuring that data is transmitted correctly between devices. The MAC sublayer adds a header to the data frame, which includes the source and destination MAC addresses, and controls the flow of data between the sender and receiver. By performing these functions, the MAC sublayer prepares the data for transmission at the physical layer.

The primary purpose of the trailer in a data link layer frame is to support frame error detection. The trailer contains a checksum or CRC (Cyclic Redundancy Check) value that is used to verify the integrity of the frame during transmission. By comparing the calculated checksum with the received checksum, errors can be detected and the frame can be discarded if necessary. This ensures that the data being transmitted is reliable and accurate.

Based on the given exhibit, there are 8 unique CRC calculations that will take place as traffic routes from the PC to the laptop. Each time the traffic passes through a device, a CRC calculation is performed to ensure data integrity. In this case, the traffic passes through 4 devices (switches and routers) before reaching the laptop, resulting in a total of 8 CRC calculations.

Layer 2 may identify devices by a physical address burned into the network card. This is true because Layer 2, also known as the Data Link Layer, uses MAC addresses to identify devices on a local network. These addresses are unique to each network card and are burned into the hardware.

Layer 3 represents a hierarchical addressing scheme. This is true because Layer 3, also known as the Network Layer, uses IP addresses to identify devices on a network. IP addresses are organized in a hierarchical manner, with different levels such as network, subnet, and host addresses, allowing for efficient routing of data across networks.

The correct answer is Network 1 uses CSMA/CD and Network 3 uses CSMA/CA. This means that Network 1 uses Carrier Sense Multiple Access with Collision Detection, which is a media access control method used in Ethernet networks. Network 3, on the other hand, uses Carrier Sense Multiple Access with Collision Avoidance, which is a media access control method used in wireless networks.

The primary purpose of encapsulating packets into frames is to facilitate the entry and exit of data on media. Encapsulation involves adding a header and a trailer to the packet, creating a frame. This frame is then transmitted over the network media, allowing the data to be sent from one device to another. The header contains information such as source and destination addresses, while the trailer contains error-checking information. This encapsulation process enables the data to be properly transmitted and received by devices on the network.

Host A will place the MAC address 00-0c-85-cf-65-c0 in the destination address field of Ethernet frames destined for http://www.server.

Logical topologies refer to the way data is transmitted between devices in a network, while physical topologies refer to the physical layout of the network. The physical topology can vary, such as being a star, bus, or ring, while the logical topology remains the same regardless of the physical layout. Logical topologies are created through the use of network protocols and determine how devices communicate and transmit data. Therefore, the statement that logical topologies consist of virtual connections between nodes is true.

A physical topology is a type of drawing that provides a graphic representation of where the company network wiring and equipment are located in the building. This drawing shows the physical layout of the network, including the placement of cables, switches, routers, and other network devices. It helps the network administrator understand the physical connections and arrangement of the network infrastructure, which is essential for troubleshooting, maintenance, and planning network expansions or modifications.

The data link layer is responsible for providing for the exchange of data over a common local media. This means that it handles the transmission of data between devices on the same network, ensuring that the data is properly formatted and delivered over the shared medium. It is not responsible for end-to-end delivery of data between hosts or between two applications, as these functions are typically handled by higher layers of the network protocol stack.

The purpose of the preamble in an Ethernet frame is to provide timing synchronization with alternating patterns of ones and zeros. This allows the receiving device to synchronize its clock with the transmitting device, ensuring that the data is transmitted and received accurately. The preamble helps establish a consistent timing reference between the devices involved in the communication process.

A characteristic of a logical point-to-point topology is that the media access control protocol can be very simple. In a point-to-point topology, there is a direct connection between two nodes, allowing for a dedicated communication channel. Since there are only two nodes involved, the media access control protocol does not need to handle the complexity of multiple nodes contending for the same channel. This simplicity in the media access control protocol is a characteristic of a logical point-to-point topology.

The source MAC address in the frame will be the MAC address of the Fa0/1 interface on RouterB because the frame is leaving RouterB. The source IP address in the frame will be the IP address of the PC because the frame is being sent from the PC to the laptop.

The logical token-passing topology is a network configuration where computers are only allowed to transmit data when they possess a token. This token is passed sequentially from one computer to another in the network. This ensures that network usage is on a first come, first serve basis, as only the computer with the token can transmit data at a given time. Additionally, data from a host is received by all other hosts in the network. This topology helps prevent high collision rates, as only one computer can transmit data at a time.

When a device is moved from one network or subnet to another, two facts are true:

1. The device will still operate at the same Layer 2 address: The Layer 2 address, also known as the MAC address, is tied to the physical network interface card (NIC) of the device. Regardless of the network or subnet it is connected to, the device will retain its MAC address.

2. The Layer 3 address must be reassigned to allow communications to the new network: The Layer 3 address, also known as the IP address, is tied to the network or subnet. When a device is moved to a new network or subnet, it needs to be assigned a new IP address that is compatible with the new network's addressing scheme in order to communicate with devices on that network.

Contention-based media access is a method used for accessing a shared media in a network. In this method, multiple devices contend for the same media, leading to non-deterministic behavior as the order of access is not predefined. This can result in collisions, where two or more devices try to transmit data simultaneously, causing data loss or corruption. However, contention-based media access has the advantage of having less overhead compared to other methods, as devices do not need to wait their turn or use token passing mechanisms. Therefore, the correct options for properties of contention-based media access are non-deterministic, less overhead, and collisions exist.

When implementing a Layer 2 protocol in a network, three factors that should be considered are the geographic scope of the network, the physical layer implementation, and the number of hosts to be interconnected. The geographic scope of the network determines the size and reach of the network, which can affect the choice of Layer 2 protocol. The physical layer implementation refers to the hardware and cabling used in the network, which can also impact the choice of protocol. Finally, the number of hosts to be interconnected influences the scalability and performance requirements of the Layer 2 protocol.

Valid Ethernet Layer 2 addresses have three characteristics. Firstly, they are 48 binary bits in length, which means they consist of 48 digits of 0s and 1s. Secondly, they are considered physical addresses, as they are assigned to the physical network interface card (NIC) of a device. Lastly, they are generally represented in hexadecimal format, which uses a combination of digits (0-9) and letters (A-F). These characteristics help in uniquely identifying devices on an Ethernet network and determining the data path through the network.

The method of media access control is determined by media sharing and logical topology. Media sharing refers to how multiple devices share the same communication medium, such as Ethernet cables or wireless channels. The method used to access the media and transmit data depends on how it is shared among devices. Logical topology, on the other hand, refers to how devices are logically connected in a network, such as in a bus, ring, or star topology. The specific method of media access control will vary depending on the chosen logical topology.

Ethernet utilizes CSMA/CD, which stands for Carrier Sense Multiple Access with Collision Detection. This means that before sending data, devices on the Ethernet network listen to see if the medium is currently being used by another device. If it is, they wait for a random amount of time before attempting to send their data again. This helps to avoid collisions and ensure efficient use of the network. The placement of data frames on the media refers to how data is transmitted and received on the physical medium, such as cables or wireless signals. Data Link layer protocols, such as Ethernet, define the rules and procedures for accessing different types of media.