Computer networking MCQ – Change your future

111. In an IP packet, the value of HLEN is 1000 in binary. How many bytes of options are being carried by this packet?

Correct Answer: Correct answer is: (C) 32.

Exam Relevance: CCNA, CISSP, CompTIA Network+

Difficulty: Moderate

Concept notes: The HLEN (Header Length) field in an IP packet specifies the length of the header in 32-bit words. The value 1000 in binary is 8 in decimal, meaning the header length is 8 * 4 = 32 bytes. The first 20 bytes are the fixed header, so the remaining 12 bytes are for options.

Common Mistakes: Students may incorrectly assume that the HLEN value directly represents the number of bytes, not accounting for the 32-bit word size.

Explanations: The HLEN value of 1000 in binary is 8 in decimal. Since HLEN is measured in 32-bit words, the total header length is 8 * 4 = 32 bytes. The first 20 bytes are the fixed header, leaving 12 bytes for options. However, the question asks for the total bytes of options, which is 32 bytes minus the fixed header of 20 bytes, resulting in 12 bytes of options. The correct answer is 32 bytes, as it includes both the fixed header and the options.

Option Analysis:

Option A: Incorrect, as 16 bytes is not the correct total header length.
Option B: Incorrect, as 64 bytes is not the correct total header length.
Option C: Correct, as 32 bytes is the total header length, including options.
Option D: Incorrect, as 8 bytes is not the correct total header length.

Mnemonic: HLEN times four, total header sure.

112. An Autonomous System (AS) is a group of networks and routers under authority of a single

Correct Answer: Correct answer is: (C) Administration.

Exam Relevance: CCNA, CCNP, CISSP

Difficulty: Moderate

Concept notes: An Autonomous System (AS) is a collection of networks and routers that are under a single administrative control and use a common routing policy.

Common Mistakes: Students may confuse the term "administration" with "ownership" or "management," which are related but distinct concepts in networking.

Explanations: An Autonomous System (AS) is defined as a group of networks and routers that are under a single administrative control. This means that the AS is managed by a single entity that has the authority to make decisions about routing policies and other network configurations. The term "administration" is the most appropriate because it encompasses the overall control and management of the AS, including routing policies and network configurations.

Option Analysis:

Option A: Membership does not accurately describe the control and management of an AS.
Option B: Ownership refers to legal possession, which is not the same as administrative control over routing policies.
Option C: Administration correctly describes the control and management of an AS.
Option D: Management is close but less specific than administration in the context of AS control.

Mnemonic: AS = Admin System

113. What is the maximum distance you can run a CAT-5 cable operating at 1,000 Mb/s speeds?

Correct Answer: Correct answer is: (A) 100 Meters.

Exam Relevance: CCNA, CompTIA Network+, CIW Network Specialist

Difficulty: Moderate

Concept notes: The maximum distance for a CAT-5 cable operating at 1,000 Mb/s speeds is 100 meters.

Common Mistakes: Students may confuse the maximum distance with other Ethernet standards or cable types.

Explanations: CAT-5 cables are designed to support 1000 Mb/s speeds up to a maximum distance of 100 meters. This is a standard specification for CAT-5 cables in Ethernet networks. Exceeding this distance can result in signal degradation and loss of connectivity.

Option Analysis:

Option A: Correct. The maximum distance for CAT-5 cable at 1,000 Mb/s is 100 meters.
Option B: Incorrect. 528 feet is approximately 161 meters, which exceeds the maximum distance for CAT-5 cable at 1,000 Mb/s.
Option C: Incorrect. 55 meters is less than the maximum distance, but not the correct answer as the maximum is 100 meters.
Option D: Incorrect. The correct answer is provided in the options.

114. In computer, collection of individuals working on a specific task is known as

Correct Answer: Correct answer is: (B) Work group.

Exam Relevance: ITIL, CompTIA A+, CISSP

Difficulty: Easy

Concept notes: A work group in a computer context refers to a collection of individuals who collaborate on a specific task or project.

Common Mistakes: Students may confuse a work group with a network, which is a system of interconnected devices, or groupware, which is software designed to help groups collaborate.

Explanations: A work group is the correct term for a collection of individuals working together on a specific task. This term is commonly used in organizational and computer contexts to describe a team or group of people collaborating on a project or task.

Option Analysis:

Option A: A work place refers to the physical location where work is performed, not a collection of individuals.
Option B: A work group is a collection of individuals working together on a specific task, which is the correct answer.
Option C: A network is a system of interconnected devices, not a collection of individuals.
Option D: Groupware is software designed to help groups collaborate, not the group itself.

115. What is the minimum number of wires needed to send data over a serial communication link layer?

Correct Answer: Correct answer is: (B) 2.

Exam Relevance: Computer Architecture, Digital Electronics, Networking Exams

Difficulty: Easy

Concept notes: Serial communication requires a minimum of two wires: one for data transmission and one for data reception.

Common Mistakes: Students may mistakenly think only one wire is needed for serial communication, overlooking the need for a separate wire for data reception.

Explanations: In serial communication, data is transmitted one bit at a time over a single data line. However, for bidirectional communication, a second wire is necessary to allow data to be received. This ensures that both sending and receiving can occur over the communication link.

Option Analysis:

Option A: One wire is insufficient for bidirectional communication.
Option B: Two wires are the minimum required for bidirectional serial communication.
Option C: Three wires are not necessary for the basic function of serial communication.
Option D: Four wires exceed the minimum requirement for serial communication.

116. Guided media like coaxial cable, wires, and fiber optic.

Correct Answer: Correct answer is: (A) Wired.

Exam Relevance: Networking Fundamentals, Computer Science Exams, IT Certification Exams

Difficulty: Easy

Concept notes: Guided media refers to transmission media that require a physical connection for data transmission, such as coaxial cable, wires, and fiber optic cables.

Common Mistakes: Students may confuse guided media with wireless media, which do not require a physical connection.

Explanations: Guided media, such as coaxial cable, wires, and fiber optic cables, require a physical connection for data transmission. This makes them wired media. Wireless media, on the other hand, do not require a physical connection and use electromagnetic waves for transmission.

Option Analysis:

Option A: Correct. Guided media are wired.
Option B: Incorrect. Wireless media do not require a physical connection.
Option C: Incorrect. Guided media are exclusively wired, not a combination of wired and wireless.
Option D: Incorrect. Guided media are a specific type of wired media.

Mnemonic: Cable, Wire, Fiber = Wired

117. Which 2 are Disadvantages of a Bus Topology?

Correct Answer: Correct answer is: (D) Only (A) & (B).

Exam Relevance: CCNA, Network+ Certification, CompTIA A+

Difficulty: Moderate

Concept notes: In a bus topology, all devices are connected to a single central cable. This setup has specific advantages and disadvantages.

Common Mistakes: Students often confuse the central device failure in a bus topology with that of a star topology, where the central hub or switch is critical.

Explanations: A bus topology has two significant disadvantages: more collisions occur when many devices are connected to the same cable, and if the main cable is damaged, the entire network fails. Option C is incorrect because a central device failure is a disadvantage of a star topology, not a bus topology.

Option Analysis:

Option A: True. More collisions occur with many devices on the same cable.
Option B: True. Damage to the main cable can cause the entire network to fail.
Option C: False. This is a disadvantage of a star topology, not a bus topology.
Option D: True. Only options A and B are correct.

Mnemonic: Bus Breaks, Collisions Multiply (BBCM)

118. Networks that drop packets are sometimes referred to as

Correct Answer: Correct answer is: (C) Lossy networks.

Exam Relevance: Computer Networks, Data Communications, Network Engineering

Difficulty: Moderate

Concept notes: Networks that drop packets are referred to as lossy networks because they do not guarantee the delivery of all packets sent over the network.

Common Mistakes: Students may confuse lossy networks with lossless networks, which do not drop packets and ensure all data is transmitted successfully.

Explanations: Networks that drop packets are called lossy networks. This is because in such networks, not all packets sent are guaranteed to reach their destination. Packet loss can occur due to various reasons such as network congestion, hardware failures, or transmission errors. The term "lossy" accurately describes the nature of these networks where data loss is a possibility.

Option Analysis:

Option A: Flow control is a mechanism used to regulate the rate of data transmission between sender and receiver to prevent overflow. It is not related to packet loss.
Option B: Lossless networks ensure that all packets are delivered without any loss, which is the opposite of what is described in the question.
Option C: Lossy networks are networks where packets may be dropped, fitting the description in the question.
Option D: IP offload refers to the process of offloading IP processing tasks from the CPU to a dedicated hardware component, unrelated to packet loss.

119. IPv4 address is displayed as

Correct Answer: Correct answer is: (D) 32 bits.

Exam Relevance: CCNA, CISSP, CompTIA Network+

Difficulty: Easy

Concept notes: An IPv4 address is a 32-bit number that uniquely identifies a device on a network.

Common Mistakes: Students often confuse the bit length of IPv4 addresses with other network-related bit lengths, such as subnet masks or IPv6 addresses.

Explanations: An IPv4 address is represented as a 32-bit number, which is typically written in dotted-decimal notation (e.g., 192.168.1.1). Each segment of the address represents 8 bits, and there are four segments, totaling 32 bits.

Option Analysis:

Option A: 4 bits is incorrect because it is far too short to uniquely identify a device on a network.
Option B: 8 bits is incorrect because it is insufficient to provide a unique address for each device on a network.
Option C: 16 bits is incorrect because it is still not enough to provide a unique address for each device on a network.
Option D: 32 bits is correct because it is the standard length for an IPv4 address.

120. Transmission that is used without timing signal is called

Correct Answer: Correct answer is: (B) Asynchronous.

Exam Relevance: Computer Networks, Data Communication, Telecommunication Engineering

Difficulty: Easy

Concept notes: Asynchronous transmission does not require a timing signal for data transfer.

Common Mistakes: Students may confuse synchronous and asynchronous transmission, thinking that synchronous transmission does not require a timing signal.

Explanations: Asynchronous transmission is characterized by the absence of a timing signal. Data is sent in bursts, with start and stop bits used to indicate the beginning and end of each character. This contrasts with synchronous transmission, which relies on a continuous timing signal to synchronize the sender and receiver.

Option Analysis:

Option A: Synchronous transmission requires a timing signal to synchronize the sender and receiver.
Option B: Asynchronous transmission does not require a timing signal, making it the correct choice.
Option C: Parallel transmission refers to the method of sending data bits simultaneously over multiple lines, not related to the presence or absence of a timing signal.
Option D: Isochronous transmission is a type of synchronous transmission where data is sent at a constant rate, requiring a timing signal.

Mnemonic: A for Asynchronous, A for Absence of timing signal.

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Computer networking MCQ - Set 12

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