Computer networking MCQ

1131. An organization is granted the block 130.34.12.64/26. The organization needs four subnetworks, each with an equal number of hosts. What is the number of addresses to each subnetwork?

Correct Answer: Correct answer is: (B) 16.

Exam Relevance: CCNA, CISSP, CompTIA Network+

Difficulty: Moderate

Concept notes: The organization needs to divide the given block into four subnetworks with an equal number of hosts. The original block is 130.34.12.64/26, which provides 64 addresses (2^6). Dividing this into four equal subnetworks means each subnetwork will have 16 addresses (64/4).

Common Mistakes: Students may mistakenly calculate the number of addresses per subnetwork by dividing the total number of addresses by the number of subnetworks without considering the need for a subnet mask that supports the division.

Explanations: The original block 130.34.12.64/26 provides 64 addresses. To create four subnetworks, we need to divide these addresses equally. Each subnetwork will have 16 addresses (64/4). This division is possible by using a subnet mask that supports the creation of four subnetworks, which is /28 (255.255.255.240). Each subnetwork will have 16 addresses, including the network and broadcast addresses.

Option Analysis:

Option A: Incorrect, as 4 addresses per subnetwork is too few.
Option B: Correct, as 16 addresses per subnetwork is the correct division.
Option C: Incorrect, as 8 addresses per subnetwork is not enough for four subnetworks.
Option D: Incorrect, as 32 addresses per subnetwork exceeds the total available addresses.

1132. Domain names are always read from the

Correct Answer: Correct answer is: (A) Node up to the root.

Exam Relevance: CCNA, CISSP, CompTIA Network+

Difficulty: Easy

Concept notes: Domain names are structured in a hierarchical manner, with the root domain at the top and more specific subdomains below it.

Common Mistakes: Students may confuse the direction of reading domain names, thinking it starts from the root down to the node.

Explanations: Domain names are read from the node up to the root. This means that the most specific part of the domain name is read first, followed by progressively less specific parts until reaching the root domain. For example, in the domain name "www.example.com", "www" is the node, "example" is the subdomain, and "com" is the root domain.

Option Analysis:

Option A: Correct. Domain names are read from the node up to the root.
Option B: Incorrect. This would imply reading from the most specific part to the least specific part, which is not how domain names are structured.
Option C: Incorrect. Reading from the root to the child would be the opposite of how domain names are structured.
Option D: Incorrect. Not all options are correct; only option A is correct.

Mnemonic: Node Up, Root Down (NURD)

1133. In..... queuing, packets are first assigned to a priority class. Each class has its own queue.

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

Exam Relevance: Computer Networks, Data Communications, Network Engineering

Difficulty: Moderate

Concept notes: In priority queuing, packets are assigned to different priority classes, and each class has its own queue.

Common Mistakes: Students may confuse priority queuing with weighted fair queuing, where packets are assigned weights rather than priority classes.

Explanations: Priority queuing involves assigning packets to different priority classes. Each class has its own queue, and packets are processed based on their priority level. This ensures that higher-priority packets are serviced before lower-priority packets, which is why the correct answer is Priority.

Option Analysis:

Option A: FIFO (First-In-First-Out) queuing does not involve assigning packets to priority classes. Packets are processed in the order they arrive.
Option B: Priority queuing involves assigning packets to different priority classes, each with its own queue.
Option C: Weighted fair queuing assigns weights to packets rather than placing them into priority classes.
Option D: This option is incorrect as the correct answer is Priority queuing.

1134. Which network is this? I allow computers to communicate with each other in across the world

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

Exam Relevance: CCNA, CompTIA Network+, ITIL Foundation

Difficulty: Easy

Concept notes: WAN stands for Wide Area Network, which allows computers to communicate over large geographical areas, including across the world.

Common Mistakes: Students may confuse WAN with LAN (Local Area Network), which is limited to a smaller geographical area, such as a single building or campus.

Explanations: WAN is the correct answer because it is designed to connect computers over large distances, including across the world. This capability distinguishes it from LAN, which is limited to a local area.

Option Analysis:

Option A: LAN (Local Area Network) is incorrect because it is limited to a local area, such as a single building or campus, and does not cover global communication.
Option B: WAN (Wide Area Network) is correct because it allows communication across large geographical areas, including globally.
Option C: Either (A) or (B) is incorrect because only WAN can support global communication.
Option D: Neither (A) nor (B) is incorrect because WAN is the correct network type for global communication.

Mnemonic: WAN - World Area Network

1135. Busy Waiting is found in.....

Correct Answer: Correct answer is: (C) 1-persistent CSMA.

Exam Relevance: Computer Networks, Data Communications, Network Protocols

Difficulty: Moderate

Concept notes: In 1-persistent CSMA, a station immediately attempts to retransmit a frame as soon as the channel becomes idle after a collision or when the station has a frame to send.

Common Mistakes: Students often confuse 1-persistent CSMA with non-persistent CSMA, where the station waits for a random period before checking the channel again.

Explanations: 1-persistent CSMA involves a station continuously listening to the channel and immediately transmitting when the channel is found to be idle. This behavior is known as busy waiting, as the station is constantly checking the channel status without any delay. This contrasts with non-persistent CSMA, where the station waits for a random period before checking the channel again, and with ALOHA and Slotted ALOHA, which do not involve continuous channel monitoring.

Option Analysis:

Option A: ALOHA does not involve busy waiting as it allows stations to transmit at any time without checking the channel status.
Option B: Slotted ALOHA involves time slots but does not continuously monitor the channel for busy waiting.
Option C: 1-persistent CSMA involves continuous channel monitoring and immediate transmission when the channel is idle, which is busy waiting.
Option D: Non-persistent CSMA involves waiting for a random period before checking the channel, not busy waiting.

1136. 100Base-T4 uses..... line coding.

Correct Answer: Correct answer is: (B) 8B6T.

Exam Relevance: CCNA, CompTIA Network+, IEEE 802 Standards

Difficulty: Moderate

Concept notes: 100Base-T4 uses 8B6T line coding to transmit data over four pairs of Category 3 or better unshielded twisted pair (UTP) cables.

Common Mistakes: Students often confuse 8B6T with other line coding schemes like MLT-3, which is used in 100Base-TX.

Explanations: 100Base-T4 is a Fast Ethernet standard that operates at 100 Mbps over four pairs of twisted pair cables. It uses 8B6T line coding, which encodes 8 bits of data into 6 ternary (three-level) signals. This coding scheme allows efficient use of the available bandwidth and reduces the complexity of the hardware required for transmission. The 8B6T coding is specifically designed to work with the constraints of Category 3 or better UTP cables, ensuring reliable data transmission at 100 Mbps.

Option Analysis:

Option A: NRZ (Non-Return-to-Zero) is a line coding scheme that does not apply to 100Base-T4.
Option B: 8B6T is the correct line coding scheme used in 100Base-T4.
Option C: MLT-3 (Multi-Level Transmission with 3 levels) is used in 100Base-TX, not 100Base-T4.
Option D: Manchester coding is used in 10Base-T, not 100Base-T4.

Mnemonic: 8B6T: "Eight Bits Six Ternary"

1137. Transmission mode controls the direction of signal flow.

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

Exam Relevance: GATE, GRE, CCNA

Difficulty: Easy

Concept notes: Transmission mode refers to the direction of data flow in a communication channel.

Common Mistakes: Students may confuse transmission mode with other communication parameters like baud rate or data encoding.

Explanations: Transmission mode controls the direction of signal flow in a communication channel. It can be simplex (one-way), half-duplex (one-way at a time), or full-duplex (two-way simultaneously). Therefore, the statement that transmission mode controls the direction of signal flow is true.

Option Analysis:

Option A: Correct, as transmission mode indeed controls the direction of signal flow.
Option B: Incorrect, as transmission mode does control the direction of signal flow.
Option C: Incorrect, as the statement is definitively true and not conditional.
Option D: Incorrect, as the statement can be determined to be true based on the definition of transmission mode.

1138. An IGMP query is sent from a..... to a.....

Correct Answer: Correct answer is: (C) Router; host or router.

Exam Relevance: CCNA, CCNP, Network+

Difficulty: Moderate

Concept notes: IGMP (Internet Group Management Protocol) queries are used to discover multicast group membership on a network. These queries are sent by routers to determine which hosts are members of specific multicast groups.

Common Mistakes: Students may mistakenly believe that IGMP queries are sent from a host to a router, not realizing that routers are responsible for managing multicast group membership.

Explanations: IGMP queries are sent by routers to hosts or other routers to discover which hosts are members of specific multicast groups. This process is essential for managing multicast traffic efficiently. The router sends the query to a multicast address, which is received by all hosts on the network segment. Hosts that are members of the queried multicast group will respond to the query, allowing the router to maintain an accurate list of group members.

Option Analysis:

Option A: Incorrect because IGMP queries are not sent from a host to another host.
Option B: Incorrect because IGMP queries are not sent from a host to a router.
Option C: Correct because IGMP queries are sent from a router to hosts or other routers.
Option D: Incorrect because the correct answer is provided in option C.

Mnemonic: R2H2R: Router to Host or Router

1139. The "IPX delay number" command will allow an administrator to change the default settings. What are the default settings?

Correct Answer: Correct answer is: (A) For LAN interfaces, one tick; for WAN interfaces, six ticks.

Exam Relevance: CCNA, Network+ Certification

Difficulty: Moderate

Concept notes: The IPX delay number command is used to adjust the delay settings for IPX interfaces. The default settings are crucial for network performance and reliability.

Common Mistakes: Students often confuse the default settings for LAN and WAN interfaces, leading to incorrect configuration and potential network issues.

Explanations: The default settings for the IPX delay number command are one tick for LAN interfaces and six ticks for WAN interfaces. This configuration ensures optimal performance by accounting for the typical delay characteristics of each type of interface. LAN interfaces generally have lower latency, hence the lower delay setting, while WAN interfaces typically have higher latency, necessitating a higher delay setting.

Option Analysis:

Option A: Correct. The default settings are one tick for LAN interfaces and six ticks for WAN interfaces.
Option B: Incorrect. This option reverses the default settings for LAN and WAN interfaces.
Option C: Incorrect. This option suggests zero ticks for LAN interfaces, which is not the default setting.
Option D: Incorrect. This option suggests zero ticks for WAN interfaces, which is not the default setting.

Mnemonic: LAN 1, WAN 6

1140. Data communications are transfer of data through some

Correct Answer: Correct answer is: (A) Transmission medium.

Exam Relevance: Computer Networks, Data Communication, Information Technology

Difficulty: Easy

Concept notes: Data communications involve the transfer of data from one point to another through a medium.

Common Mistakes: Students may confuse the transmission medium with protocols or network types, which are different components of data communication systems.

Explanations: Data communications require a physical or logical pathway for data to travel from the source to the destination. This pathway is known as the transmission medium. Examples of transmission media include cables, optical fibers, and wireless signals. Protocols, networks, and linear media are not the direct means of data transfer.

Option Analysis:

Option A: Correct. Transmission medium is the pathway through which data is transferred.
Option B: Incorrect. Linear medium is not a standard term in data communications.
Option C: Incorrect. Network LAN (Local Area Network) is a type of network, not a transmission medium.
Option D: Incorrect. Protocols are rules and standards for data communication, not the medium through which data is transferred.

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Computer networking MCQ - Set 114

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