Computer networking MCQ

1181. ICMP messages are divided into two broad categories:.....

Correct Answer: Correct answer is: (A) Query and error reporting messages.

Exam Relevance: CCNA, CISSP, CompTIA Network+

Difficulty: Easy

Concept notes: ICMP (Internet Control Message Protocol) is used for error reporting and diagnostic functions in IP networks. ICMP messages are categorized into two main types: query messages and error reporting messages.

Common Mistakes: Students may confuse ICMP messages with TCP or UDP messages, which are different protocols used for different purposes.

Explanations: ICMP messages are divided into two broad categories: query messages and error reporting messages. Query messages are used for diagnostic purposes, such as pinging a host to check its reachability. Error reporting messages are used to report issues encountered by routers or hosts, such as unreachable destinations or packet timeouts. This categorization is fundamental to understanding how ICMP functions within the network.

Option Analysis:

Option A: Correct. ICMP messages are indeed divided into query and error reporting messages.
Option B: Incorrect. Request and response messages are not the correct categories for ICMP messages.
Option C: Incorrect. Request and reply messages are not the correct categories for ICMP messages.
Option D: Incorrect. The correct categories are provided in Option A.

1182. The L band has the Up-link of

Correct Answer: Correct answer is: (A) 1.6 GHz.

Exam Relevance: GATE, GRE, JE

Difficulty: Easy

Concept notes: The L band is a frequency range used in satellite communications, particularly for uplink and downlink signals.

Common Mistakes: Students may confuse the L band with other frequency bands used in satellite communications, such as the S band or C band.

Explanations: The L band is defined as the frequency range from 1 to 2 GHz. The uplink frequency for the L band is typically around 1.6 GHz, which is used for transmitting signals from the ground station to the satellite.

Option Analysis:

Option A: Correct, as 1.6 GHz is the uplink frequency for the L band.
Option B: Incorrect, as 1.8 GHz is not the uplink frequency for the L band.
Option C: Incorrect, as 2.5 GHz is outside the L band range.
Option D: Incorrect, as 5 GHz is not within the L band range.

Mnemonic: L band, Low, 1.6

1183. When a host sees that no process is interested in a specific group, it sends a

Correct Answer: Correct answer is: (C) Leave report.

Exam Relevance: CCNA, CCNP, Network+

Difficulty: Moderate

Concept notes: When a host determines that no process is interested in a specific multicast group, it sends a leave report to indicate that it no longer wishes to receive traffic for that group.

Common Mistakes: Students may confuse the leave report with a join report, which is sent when a host wants to start receiving traffic for a multicast group.

Explanations: A leave report is sent by a host to indicate that it no longer wishes to receive traffic for a specific multicast group. This is a standard procedure in multicast communication to ensure that traffic is only sent to interested hosts, thereby conserving network resources.

Option Analysis:

Option A: A logical report is not a standard term in multicast communication and does not apply to the scenario described.
Option B: A local report is not a standard term in multicast communication and does not apply to the scenario described.
Option C: A leave report is the correct term used in multicast communication to indicate that a host no longer wishes to receive traffic for a specific group.
Option D: A joining report is sent when a host wants to start receiving traffic for a multicast group, which is the opposite of the scenario described.

1184. Which range of link-local addresses can be assigned to an IPv6-enabled interface?

Correct Answer: Correct answer is: (C) FE80::/10.

Exam Relevance: CCNA, CISSP, CompTIA Network+

Difficulty: Moderate

Concept notes: Link-local addresses in IPv6 are used for communication between devices on the same link without the need for a router. The range FE80::/10 is reserved for these addresses.

Common Mistakes: Students may confuse the link-local address range with other special IPv6 address ranges, such as multicast or unique local addresses.

Explanations: The range FE80::/10 is specifically designated for link-local addresses in IPv6. These addresses are automatically assigned to each interface and are used for communication within the same local network segment. The prefix FE80::/10 ensures that these addresses are unique within the local link and are not routable outside of it.

Option Analysis:

Option A: FEC0::/10 is the range for site-local addresses, which are deprecated in IPv6.
Option B: FDEE::/7 is not a standard IPv6 address range.
Option C: FE80::/10 is the correct range for link-local addresses.
Option D: FF00::/8 is the range for multicast addresses, not link-local addresses.

1185. P-persistent method is used if time slots with a slot duration equal to or greater than maximum of

Correct Answer: Correct answer is: (C) Propagation Time.

Exam Relevance: Computer Networks, Data Communications, Network Protocols

Difficulty: Moderate

Concept notes: In the P-persistent method, the time slots must be at least as long as the propagation time to ensure that a station can detect a collision before transmitting.

Common Mistakes: Students often confuse propagation time with collision time, which is not the critical factor in determining the slot duration for P-persistent CSMA.

Explanations: The P-persistent method requires that the time slots be long enough to allow a station to detect a collision before it starts transmitting. This ensures that a station can sense the channel and avoid transmitting if another station is already transmitting. The propagation time is the time it takes for a signal to travel from one end of the network to the other. If the time slot is shorter than the propagation time, a station might not detect a collision before transmitting, leading to potential collisions. Therefore, the time slot must be at least as long as the propagation time to ensure proper collision detection.

Option Analysis:

Option A: Collision Time is not the critical factor for determining the slot duration in P-persistent CSMA.
Option B: Sense Time is the time it takes to detect the channel status, but it is not the determining factor for the slot duration.
Option C: Propagation Time is the correct factor because it ensures that a station can detect a collision before transmitting.
Option D: Navigation Time is not a relevant factor in this context.

1186. Bluetooth uses

Correct Answer: Correct answer is: (A) Frequency hoping spread spectrum.

Exam Relevance: IEEE 802.15.1, Wireless Communication Exams, Network Engineering Exams

Difficulty: Easy

Concept notes: Bluetooth technology uses frequency hopping spread spectrum (FHSS) to transmit data over short distances.

Common Mistakes: Students may confuse frequency hopping spread spectrum with other modulation techniques like orthogonal frequency division multiplexing (OFDM) or time division multiplexing (TDM).

Explanations: Bluetooth employs frequency hopping spread spectrum (FHSS) to avoid interference and ensure reliable communication. FHSS rapidly switches the carrier frequency among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. This technique helps in reducing interference and improving security.

Option Analysis:

Option A: Correct. Bluetooth uses frequency hopping spread spectrum (FHSS) for its communication protocol.
Option B: Incorrect. Orthogonal frequency division multiplexing (OFDM) is used in other wireless technologies like Wi-Fi, not Bluetooth.
Option C: Incorrect. Time division multiplexing (TDM) is not used in Bluetooth technology.
Option D: Incorrect. Frequency hopping spread spectrum (FHSS) is indeed used in Bluetooth.

1187. Modulation technique that has become standard for Asymmetric Digital Subscriber Line (ADSL) is called the

Correct Answer: Correct answer is: (A) Discrete multitoned technique.

Exam Relevance: Networking exams, Telecommunications exams, Computer Science exams

Difficulty: Moderate

Concept notes: Discrete multitone (DMT) is a modulation technique used in ADSL to transmit data over telephone lines. It divides the available bandwidth into multiple sub-channels, each carrying a portion of the data.

Common Mistakes: Students may confuse DMT with other modulation techniques like frequency modulation or adaptive modulation, which are not the standard for ADSL.

Explanations: Discrete multitone (DMT) is the standard modulation technique for ADSL. It divides the available bandwidth into multiple sub-channels, each carrying a portion of the data. This allows for efficient use of the available bandwidth and helps to mitigate the effects of noise and interference. The other options, such as adaptive technique, quantity asynchronous modulation, and frequency modulation, are not the standard techniques used in ADSL.

Option Analysis:

Option A: Discrete multitone (DMT) is the correct modulation technique used in ADSL.
Option B: Adaptive technique is not the standard modulation technique for ADSL.
Option C: Quantity asynchronous modulation is not a standard term used in ADSL.
Option D: Frequency modulation is not the standard modulation technique for ADSL.

Mnemonic: DMT: Divide, Modulate, Transmit

1188. When a DNS server accepts and uses incorrect information from a host that has no authority giving that information, then it is called

Correct Answer: Correct answer is: (C) DNS spoofing.

Exam Relevance: CISSP, CompTIA Security+, CCNA Security

Difficulty: Moderate

Concept notes: DNS spoofing occurs when a DNS server accepts and uses incorrect information from a host that has no authority to provide that information.

Common Mistakes: Students may confuse DNS spoofing with DNS hijacking, which involves redirecting traffic to a different server.

Explanations: DNS spoofing involves the DNS server accepting and using incorrect information from an unauthorized source. This incorrect information can lead to users being directed to malicious websites instead of the intended ones. The term "spoofing" refers to the act of masquerading as an authorized entity to deceive the DNS server into accepting false data.

Option Analysis:

Option A: DNS lookup is the process of resolving a domain name to an IP address and does not involve incorrect information.
Option B: DNS hijacking involves redirecting traffic to a different server, not necessarily using incorrect information from unauthorized sources.
Option C: DNS spoofing is the correct term for when a DNS server accepts and uses incorrect information from unauthorized sources.
Option D: This option is incorrect as DNS spoofing is the correct term for the described scenario.

Mnemonic: Spoofing = Spoofed Sources

1189. In TCP, each connection have

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

Exam Relevance: Computer Networks, CCNA, CISSP

Difficulty: Easy

Concept notes: TCP (Transmission Control Protocol) establishes a full-duplex connection, allowing data to be sent and received simultaneously.

Common Mistakes: Students may mistakenly believe that TCP only supports one stream of data, similar to how some other protocols operate.

Explanations: TCP connections are full-duplex, meaning they support two streams of data: one for sending and one for receiving. This allows for simultaneous data transfer in both directions, enhancing the efficiency of the connection.

Option Analysis:

Option A: Incorrect, as TCP supports two streams, not one.
Option B: Correct, TCP supports two streams for full-duplex communication.
Option C: Incorrect, as TCP does not support three streams.
Option D: Incorrect, as TCP does not support an infinite number of streams.

1190. Transmission impairment that refers to a signal with high energy in a very short time is

Correct Answer: Correct answer is: (D) Impulse Noise.

Exam Relevance: Networking Exams, Telecommunications Exams, Digital Communications Exams

Difficulty: Moderate

Concept notes: Impulse noise refers to a type of transmission impairment characterized by high-energy signals that occur in very short durations.

Common Mistakes: Students may confuse impulse noise with thermal noise, which is a continuous random noise, or cross talk, which is interference from adjacent channels.

Explanations: Impulse noise is defined by its high energy in short bursts, making it distinct from other types of noise. Thermal noise is a continuous random noise due to thermal agitation of electrons, while cross talk is interference from adjacent channels. Induced noise is typically caused by external electromagnetic interference. Therefore, impulse noise is the correct answer as it matches the description of a signal with high energy in a very short time.

Option Analysis:

Option A: Thermal Noise is a continuous random noise due to thermal agitation of electrons and does not fit the description of high energy in short bursts.
Option B: Induced Noise is caused by external electromagnetic interference and is not characterized by high energy in short bursts.
Option C: Cross talk is interference from adjacent channels and does not describe high energy in short bursts.
Option D: Impulse Noise is characterized by high energy in very short durations, fitting the description given in the question.

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Computer networking MCQ - Set 119

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