Computer Networks MCQ Quiz - Objective Question with Answer for Computer Networks - Download Free PDF

The correct answer is Bus topology.

Key Points

• Logical topology refers to the way data is transmitted within the network, regardless of its physical design.
• In a twisted pair Ethernet network with a physical star topology, all devices are connected to a central hub or switch.
• However, the logical topology of such a network is a bus topology because data is broadcast to all devices, similar to how it would be in a bus network.

Additional Information

• Tree topology: This is a hybrid topology that combines characteristics of star and bus topologies. It is not the logical topology for a twisted pair Ethernet network.
• Star topology: This is the physical topology where each node is connected to a central hub. However, it does not describe the logical data transmission method.
• Mesh topology: In this topology, each node is connected to every other node. This is neither the physical nor logical topology for a twisted pair Ethernet network.

The correct answer is To convert domain names into IP addresses.

Key Points

• The Domain Name System (DNS) Server is a crucial component in networking that translates human-friendly domain names into machine-readable IP addresses.
  • When a user types a domain name into their web browser, the DNS server is queried to find the corresponding IP address.
  • This translation is necessary because while domain names are easy for humans to remember, computers use IP addresses to locate each other on the network.
  • DNS servers help to ensure that the internet runs smoothly by keeping track of all domain names and their IP addresses.
  • Without DNS servers, users would have to remember and input numerical IP addresses to access websites, which is impractical.
  • DNS servers also provide additional functionalities like email routing and service discovery within networks.

Additional Information

• DNS servers are structured in a hierarchical manner, starting from root servers down to local servers.
• They can cache DNS queries to speed up the resolution process for frequently accessed domain names.
• DNS servers use different types of records such as A records (address records), CNAME records (canonical name records), and MX records (mail exchange records).
• Security extensions like DNSSEC (DNS Security Extensions) add an additional layer of security by ensuring the authenticity and integrity of DNS data.
• The DNS system was introduced by Paul Mockapetris and Jon Postel in 1983.

Explanation:

DMA Acknowledgement Signal

Definition: The Direct Memory Access (DMA) controller is a hardware component used in computer systems to manage the flow of data directly between memory and peripherals without involving the CPU, thereby freeing the CPU to perform other tasks. When a peripheral device requests the DMA controller for data transfer, the DMA controller sends an acknowledgment signal known as DMA Acknowledge (DACK) to the peripheral device to indicate that it is ready to handle the data transfer.

Correct Option Analysis:

The correct option is:

Option 2: MPU sends the HLDA signal

When the DMA controller initiates a data transfer, it sends a request to the Microprocessor Unit (MPU) to relinquish control of the data bus. The MPU responds by sending a Hold Acknowledge (HLDA) signal to the DMA controller, indicating that it has released control of the buses. Upon receiving the HLDA signal, the DMA controller sends the DMA Acknowledge (DACK) signal to the peripheral to start the data transfer.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: Higher address bus A8-A15 is available on the address bus

This option is incorrect because the availability of the higher address bus A8-A15 does not directly relate to the DMA acknowledgment signal. The higher address bus lines are used for addressing memory locations, but they do not indicate when the DMA controller is ready to handle data transfers. The DMA acknowledgment signal is specifically related to the communication between the DMA controller and the peripheral device.

Option 3: Entire address bus A0-A15 is available on the address bus

This option is also incorrect because the availability of the entire address bus A0-A15 is not the condition for the DMA acknowledgment signal. While the address bus is crucial for specifying memory locations during data transfers, the DMA acknowledgment signal involves the control and coordination between the DMA controller and the peripheral device, indicating readiness for data transfer.

Option 4: Lower address bus A0-A7 is available on the address bus

This option is incorrect for similar reasons as options 1 and 3. The availability of the lower address bus A0-A7 does not directly relate to the DMA acknowledgment signal. The lower address bus lines are part of the overall addressing scheme, but they do not play a role in signaling the readiness of the DMA controller to the peripheral device.

Conclusion:

Understanding the role of the DMA controller and the signals involved in the data transfer process is essential for correctly identifying the conditions under which the DMA acknowledgment signal (DACK) is sent to the peripheral device. The correct option highlights the importance of the MPU sending the HLDA signal to the DMA controller, which then sends the DACK signal to the peripheral, indicating readiness for data transfer. This process ensures efficient communication and coordination between the MPU, DMA controller, and peripheral devices, optimizing the overall performance of the computer system.

Explanation:

SNMP Agent Communication with SNMP Manager

Definition: The Simple Network Management Protocol (SNMP) is a protocol used for network management. It allows network administrators to manage network performance, find and solve network problems, and plan for network growth. An SNMP-managed network consists of three key components: managed devices, agents, and a network management system (NMS). The SNMP agent is software that resides on a managed device, such as a router, switch, or server, and communicates with the SNMP manager, which is part of the NMS.

Working Principle: The SNMP agent collects data from the managed device it resides on and makes this data available to the SNMP manager upon request. The primary method by which the SNMP agent communicates with the SNMP manager is through responding to GET and SET requests. These requests allow the SNMP manager to query the agent for information (GET) or modify the configuration (SET).

Advantages:

• Enables centralized network management, allowing administrators to monitor and control multiple devices from a single location.
• Supports proactive network management by providing real-time data on network performance and issues.
• Allows for automation of network management tasks, reducing the need for manual intervention.

Disadvantages:

• Security vulnerabilities if not properly configured, as SNMP data can be intercepted if transmitted without encryption.
• Complexity in setting up and managing SNMP, requiring a good understanding of network management principles.

Applications: SNMP is widely used in network management systems for monitoring network-attached devices for conditions that warrant administrative attention. It is commonly used in data centers, large enterprise networks, and telecommunications networks.

Correct Option Analysis:

The correct option is:

Option 2: By responding to GET and SET requests from the SNMP Manager.

This option accurately describes the primary method of communication between the SNMP agent and the SNMP manager. The SNMP agent responds to GET requests from the SNMP manager to provide information about the managed device and to SET requests to configure or modify settings on the managed device.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: By generating encrypted data streams.

This option is incorrect as SNMP itself does not inherently generate encrypted data streams. While SNMPv3 does support encryption to secure the data being transmitted, it is not the primary method of communication. The fundamental communication still revolves around GET and SET requests.

Option 3: By initiating a TCP connection.

SNMP primarily uses the User Datagram Protocol (UDP) for communication, not TCP. UDP is preferred for its lower overhead and faster transmission times, although it does not guarantee delivery like TCP. Therefore, this option is incorrect.

Option 4: By sending files via FTP.

This option is incorrect as it misrepresents the nature of SNMP communication. SNMP does not use the File Transfer Protocol (FTP) for communication between the agent and the manager. SNMP operates using its own set of protocols and messages, such as GET, SET, and TRAP.

Conclusion:

Understanding the correct method of communication between the SNMP agent and the SNMP manager is crucial for effective network management. The SNMP agent primarily communicates by responding to GET and SET requests from the SNMP manager, allowing for the collection and modification of data on managed devices. This communication method is fundamental to the operation of SNMP and enables centralized, automated, and proactive network management.

The correct option is 2

CONCEPT:

Mesh is a networking topology, in which each device is connected with every other device in the network.

If any of the link connecting two devices fails, there is no effect on the communication network as  as shown in the below diagram.

Consider the link between nodes A and B fails. 

Now if A wants to communicate with B then it can communicate via nodes C and D. Thus  there is no effect on the communication network.

The correct answer is Local Area Network (LAN):

Important Points

• It is a computer network within a small geographical area.
• A LAN is composed of interconnected workstations and personal computers which are each capable of accessing and sharing data and devices, such as printers, scanners and data storage devices, anywhere on the LAN.

The correct answer is option 4) i.e. Firewall.

• A firewall is a type of computer-security system.
• A firewall controls the flow of data from one computer or network to another and they are mainly intended to protect an individual computer system or a network from being accessed by an intruder, especially via the Internet.

Note:

• Cookies are small files that are stored on a user's computer. They are designed to hold a modest amount of data specific to a particular client and website and can be accessed either by the web server or the client computer. 
• Spam is an undesired or illegal email message.
• Spyware is unwanted software that infiltrates your computing device, stealing your internet usage data and sensitive information. 

The correct answer is Modulator

Key Points

• A modulator is a device that performs signal conversion. It works by varying one or more properties of a high-frequency periodic waveform, called the carrier signal, according to a modulating signal which typically contains information to be transmitted. This process is known as modulation.
• The types of modulation include amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM), among others. These modulation techniques allow for the encoding of information into the carrier signal, which can then be transmitted over a communication channel. When the signal reaches its destination, a demodulator extracts the original information from the modulated carrier.

 Additional Information

• A mouse is a handheld pointing device that detects two-dimensional motion relative to a surface.
• A plotter is a device that creates hardcopy graphics. They are like printers, but instead of rendering text, plotters draw images using a pen.
• A keyboard is an input device used to enter text and commands into the computer. Each key represents a specific character or function.

Option 1 is the correct answer: Local Area Network (LAN) has the highest transmission speed.

The correct answer is spam.

Key Points

• Any unwanted, uninvited digital communication transmitted in bulk is referred to as spam.
• Spam is frequently transmitted by email.
• But it can also be sent through social media, text messages, and phone calls.
• Cybercriminals send phishing emails to a large number of recipients in an effort to "hook" a select few recipients.
• Phishing emails con people into disclosing private data like credit card numbers or website logins. 

Additional Information

• Virus:
  • A computer virus is a form of malware that accompanies another program and has the ability to multiply and propagate once it has been run on a machine. 
• Unzip:
  • Extraction of the files from a single-file zip archive or other comparable file archive is known as unzipping.
• URL:
  • URL stands for Uniform Resource Locator.
  • A URL is nothing more than the Web address of a specific, particular resource.

The correct answer is Botnet attack.

Key Points

• Botnet is a network of computers that have been infected with malware and are controlled by a single attacker. The attacker can use the botnet to launch a variety of attacks, including DDoS attacks.
• DDoS attack is a cyber-security attack that targets a website or server with a flood of traffic. This traffic can overwhelm the website or server, making it unavailable to legitimate users.
• Zero-day attack is an attack that exploits a vulnerability in software that the software vendor is not aware of. This means that there is no patch available to fix the vulnerability, making it very difficult to defend against.
• A spear phishing attack is a targeted attack that is designed to trick the victim into clicking on a malicious link or opening an infected attachment.
• Therefore, the term for a cyber-security attack that targets multiple interconnected devices simultaneously to create a large-scale attack network is botnet attack.

Additional Information

Here are some ways to protect yourself from botnet attacks:

• Keep your software up to date. Software vendors often release patches to fix security vulnerabilities.
• Use a firewall. A firewall can help to block malicious traffic from reaching your computer.
• Use antivirus software. Antivirus software can help to detect and remove malware from your computer.
• Be careful about what websites you visit and what links you click on.
• Do not open attachments from unknown senders.

• TELNET is the terminal emulation protocol in a TCP/IP environment for the remote access of a terminal (client) to a server.
• TELNET uses the TCP as the transport protocol to establish a connection between server and client.

The correct answer is 128 bits.

Key Points

• An IPv6 address has a size of 128 bits.
• Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet.
• IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion.
• IPv6 is intended to replace IPv4.
• 1 Bytes is equal to 8 bit

Additional Information

• IPv4 (Internet Protocol version 4) uses a 32-bit addressing scheme.
• This means that IPv4 addresses are composed of 32 binary bits, which are typically represented as four sets of decimal numbers separated by periods (e.g., 192.168.0.1).
• Each decimal number in the address represents an 8-bit segment, also known as an octet, resulting in a total of four octets in an IPv4 address.

The correct answer is Hexa decimal format

Key Points

MAC address is written in Hexadecimal format.

MAC address:

• A media access control address (MAC) is a unique identifier assigned to a network interface controller for use as a network address in communications within a network segment.
• This use is common in most IEEE 802 network technologies, including Ethernet, Wi-fi, and Bluetooth.
• Every NIC ( Network Interface Controller) has a hardware address that's known as a MAC, for media access control where IP addresses are associated with TCP/IP (networking software), MAC addresses are linked to the hardware of network adapters.
• MAC addresses are recognizable as six groups of two hexadecimal digits, separated, by hyphens, colons, or without a separator.
• A MAC address is a 48-bit number.
• A network interface controller is a computer hardware component that connects a computer to a computer network.

The correct answer is SMTP.

Key Points 

• SMTP:- The Simple Mail Transfer Protocol (SMTP) is used for the transfer of mail messages and attachments.
• IP:- The Internet Protocol (IP) is a routable protocol responsible for IP addressing and the fragmentation and reassembly of packets.
• UDP:- UDP provides a one-to-one or one-to-many, connectionless, unreliable communications service. UDP is used when the amount of data to be transferred is small.