1.
Which of the following protocols are examples of TCP/IP transport layer protocols?
Correct Answer(s)
B. UDP
D. TCP
Explanation
UDP and TCP are examples of TCP/IP transport layer protocols. UDP (User Datagram Protocol) is a connectionless protocol that provides a lightweight and fast way to send datagrams over IP networks. It is commonly used for applications that require low latency and can tolerate packet loss, such as video streaming or online gaming. TCP (Transmission Control Protocol) is a connection-oriented protocol that provides reliable, ordered, and error-checked delivery of data packets. It ensures that all packets are received in the correct order and retransmits any lost packets. TCP is commonly used for applications that require reliable data transmission, such as web browsing or file transfer.
2.
Which of the following protocols are examples of TCP/IP network access layer protocols?
Correct Answer(s)
B. Ethernet
C. PPP
Explanation
Ethernet and PPP are examples of TCP/IP network access layer protocols. The network access layer is responsible for the physical transmission of data over the network. Ethernet is a widely used protocol for wired local area networks (LANs), while PPP (Point-to-Point Protocol) is commonly used for establishing a direct connection between two nodes over a serial link. UDP, TCP, and HTTP are examples of transport layer protocols, which operate at a higher layer in the TCP/IP protocol stack.
3.
The process of HTTP asking TCP to send some data and make sure that it is received correctly is an example of what?
Correct Answer
B. Adjacent-layer interaction
Explanation
The given correct answer, "Adjacent-layer interaction," refers to the interaction between two adjacent layers in the OSI model. In this case, HTTP, which operates at the application layer, is asking TCP, which operates at the transport layer, to send data and ensure its correct reception. This interaction between the application and transport layers exemplifies adjacent-layer interaction within the OSI model.
4.
The process of TCP on one computer marking a segment as segment 1, and the receiving computer then acknowledging the receipt of segment 1, is an example of what?
Correct Answer
B. Same-layer interaction
Explanation
The process described in the question involves the interaction between the TCP layer on one computer and the receiving computer. This interaction occurs within the same layer of the OSI model, specifically the transport layer. The TCP layer on the sending computer marks the segment as segment 1, and the receiving computer acknowledges the receipt of segment 1. This interaction between the same layer of the OSI model is known as same-layer interaction.
5.
The process of a web server adding a TCP header to a web page, followed by adding an IP header, and then a data link header and trailer is an example of what?
Correct Answer
A. Data encapsulation
Explanation
The process described in the question is an example of data encapsulation. Data encapsulation refers to the process of adding headers and trailers to data as it moves through different layers of a network protocol stack. In this case, the web server is adding TCP, IP, and data link headers and trailers to the web page, which is a form of encapsulating the data for transmission over the network.
6.
Which of the following terms is used specifically to identify the entity that is created when encapsulating data inside data link layer headers and trailers?
Correct Answer
D. Frame
Explanation
The correct answer is "Frame" because in the data link layer of the OSI model, data is encapsulated into frames by adding headers and trailers. Frames are then transmitted over the physical layer.
7.
Which OSI layer defines the functions of logical network-wide addressing and routing?
Correct Answer
D. Layer 4
Explanation
Layer 4 of the OSI model, also known as the Transport layer, is responsible for end-to-end communication between hosts. It ensures the reliable and orderly delivery of data packets from the source to the destination. While Layer 3 (Network layer) handles logical addressing and routing at the network level, Layer 4 focuses on the transport of data across the network. It establishes connections, breaks data into smaller segments, and manages flow control and error recovery. Therefore, Layer 4 is the correct answer for the given question.
8.
Which OSI layer defines the standards for cabling and connectors?
Correct Answer
A. Layer 1
Explanation
Layer 1 of the OSI model, also known as the Physical layer, is responsible for defining the standards for cabling and connectors. This layer deals with the physical transmission of data over the network, including the electrical, mechanical, and functional aspects of the network interface. It specifies the characteristics of the physical media, such as cables, connectors, and signaling methods, ensuring that devices can properly communicate with each other.
9.
Which OSI layer defines the standards for data formats and encryption?
Correct Answer
D. Layer 6
Explanation
Layer 6 of the OSI model, known as the Presentation layer, is responsible for defining the standards for data formats and encryption. This layer ensures that data is properly formatted and encrypted before being transmitted between network devices. It handles tasks such as data compression, encryption, and decryption, ensuring that data is presented in a format that can be understood by the receiving device.
10.
Which of the following terms are not valid terms for the names of the seven OSI layers?
Correct Answer(s)
C. Transmission
E. Internet
Explanation
The terms "Transmission" and "Internet" are not valid terms for the names of the seven OSI layers. The OSI model consists of seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. "Transmission" does not correspond to any of these layers, and "Internet" is not one of the recognized layers in the OSI model.
11.
Which of the following is true about the cabling of a typical modern Ethernet LAN?
Correct Answer
D. Connect each device to a centralized LAN switch using UTP cabling
Explanation
A typical modern Ethernet LAN connects each device to a centralized LAN switch using UTP cabling. This is the most common configuration for Ethernet networks, where each device is connected to a switch through an Ethernet cable. The switch acts as a central point for all the devices to connect to, allowing them to communicate with each other. UTP cabling, which stands for Unshielded Twisted Pair, is the most widely used type of cabling for Ethernet networks due to its affordability and flexibility.
12.
Which of the following is true about the cabling of a 10BASE2 Ethernet LAN?
Correct Answer
A. Connect each device in series using coaxial cabling
Explanation
In a 10BASE2 Ethernet LAN, each device is connected in series using coaxial cabling. This means that the devices are connected one after another in a linear chain, with each device being connected to the previous device using coaxial cables. This type of cabling allows for the transmission of data signals between the devices in the LAN.
13.
Which of the following is true about Ethernet crossover cables?
Correct Answer
B. Pins 1 and 2 on one end of the cable connect to pins 3 and 6 on the other end of the cable.
Explanation
Ethernet crossover cables are used to connect two devices of the same type, such as two computers or two switches, without the need for a separate network hub or switch. In these cables, pins 1 and 2 on one end of the cable are connected to pins 3 and 6 on the other end. This configuration allows for the transmission and reception of data between the devices. This is different from a straight-through Ethernet cable, where pins 1 and 2 on both ends are connected to each other.
14.
Each answer lists two types of devices used in a 100BASE-TX network. If these devices were connected with UTP Ethernet cables, which pairs of devices would require a straight-through cable?
Correct Answer(s)
B. PC and switch
D. Router and hub
E. Wireless access point (Ethernet port) and switch
Explanation
The devices that would require a straight-through cable are PC and switch, Router and hub, and Wireless access point (Ethernet port) and switch. In a 100BASE-TX network, a straight-through cable is used to connect devices that are different in terms of their role in the network. A straight-through cable has the same pin configuration on both ends, allowing for proper transmission of data between devices. In this case, a PC and switch, a router and hub, and a wireless access point and switch are all different types of devices that need to be connected using a straight-through cable.
15.
Which of the following is true about the CSMA/CD algorithm?
Correct Answer
B. Collisions can happen, but the algorithm defines how the computers should notice a collision and how to recover.
Explanation
The CSMA/CD algorithm allows collisions to occur, but it provides a mechanism for the computers to detect and recover from these collisions. This algorithm is used in Ethernet networks to control access to the network medium. When two devices attempt to transmit data simultaneously and a collision occurs, the algorithm defines how the devices should detect the collision and stop transmitting. It also specifies a process for retransmitting the data after a random backoff period, reducing the likelihood of further collisions. Therefore, the answer option stating that collisions can happen, but the algorithm defines how the computers should notice a collision and how to recover is correct.
16.
Which of the following is a collision domain?
Correct Answer
A. All devices connected to an Ethernet hub
Explanation
All devices connected to an Ethernet hub are considered to be in the same collision domain. In an Ethernet network, a collision domain is a network segment where collisions can occur when two devices transmit data at the same time. In a hub-based network, all devices connected to the hub share the same bandwidth and can potentially collide with each other when transmitting data. This is because a hub forwards all incoming data to all connected devices, creating a single collision domain. In contrast, an Ethernet switch creates separate collision domains for each of its ports, reducing the likelihood of collisions.
17.
Which of the following describe a shortcoming of using hubs that is improved by instead using switches?
Correct Answer(s)
A. Hubs create a single electrical bus to which all devices connect, causing the devices to share the bandwidth.
C. Hubs allow collisions to occur when two attached devices send data at the same time.
Explanation
Using hubs creates a single electrical bus, causing all devices to share the available bandwidth. This can result in slower network speeds and decreased performance. Additionally, hubs allow collisions to occur when two devices attached to the hub send data simultaneously. This can lead to data loss and network congestion. Switches, on the other hand, provide dedicated bandwidth to each connected device and prevent collisions, resulting in faster and more efficient data transmission. Therefore, using switches improves the shortcomings of hubs in terms of bandwidth sharing and collision prevention.
18.
Which of the following terms describe Ethernet addresses that can be used to communicate with more than one device at a time?
Correct Answer(s)
C. Broadcast address
D. Multicast address
Explanation
Broadcast addresses and multicast addresses are both Ethernet addresses that can be used to communicate with more than one device at a time. A broadcast address is a special address that is used to send a message to all devices on a network, while a multicast address is used to send a message to a specific group of devices on a network.
19.
Which of the following is one of the functions of OSI Layer 2 protocols?
Correct Answer
A. Framing
Explanation
OSI Layer 2 protocols are responsible for framing, which means they add a header and trailer to the data received from Layer 3 protocols. This framing helps in identifying the start and end of a frame, as well as in error detection. By adding this additional information, Layer 2 protocols ensure that the data can be properly transmitted and received between devices on a network.
20.
Which of the following are true about the format of Ethernet addresses?
Correct Answer(s)
B. Each manufacturer puts a unique code into the first 3 bytes of the address.
C. Each manufacturer puts a unique code into the first half of the address.
E. The part of the address that holds this manufacturer's code is called the OUI.
Explanation
Ethernet addresses, also known as MAC addresses, consist of 6 bytes or 48 bits. The first 3 bytes (24 bits) of the address are known as the Organizationally Unique Identifier (OUI) and they represent the unique code assigned to each manufacturer. Therefore, the statement "Each manufacturer puts a unique code into the first 3 bytes of the address" is true. Additionally, it is also true that "Each manufacturer puts a unique code into the first half of the address" since the first 3 bytes represent half of the total address. Finally, the part of the address that holds the manufacturer's code is indeed called the OUI.
21.
Which of the following is true about the Ethernet FCS field?
Correct Answer
C. It resides in the Ethernet trailer, not the Ethernet header.
Explanation
The Ethernet FCS (Frame Check Sequence) field is used for error detection, not error recovery. It is a 4-byte long field, not 2 bytes long. The FCS field is located in the Ethernet trailer, which is the last part of the Ethernet frame, not in the Ethernet header. The FCS field is not used for encryption. Therefore, the correct answer is that the FCS field resides in the Ethernet trailer, not the Ethernet header.