Ethernet IEEE 802.3 MCQs: 12 Solved Questions with Explanations

Ethernet looks easy until similar terms appear in the same option set. Students remember that Ethernet means IEEE 802.3, then mix it with IEEE 802.11, confuse a hub with a switch, miss the progression from 10 Mb/s to 1 Gb/s, or treat a jam signal as frame padding. Ethernet IEEE 802.3 questions combine standards, speeds, devices, addressing and shared-medium collision handling. Questions 2, 4-9 and 11 link directly to their solved bank pages. For Questions 1, 3, 10 and 12, use the Ethernet IEEE 802.3 PYQ practice hub.

Ethernet IEEE 802.3 MCQs: build the concept and speed map

Use five buckets while solving. Standard and scope covers Ethernet, IEEE 802.3 and wired LANs. Evolution and rate covers Standard, Fast, Gigabit and 10 Gigabit Ethernet. Device and negotiation covers hubs, repeaters and auto-negotiation. Addressing covers the 48-bit MAC address and multicast range. Shared-medium behaviour covers collision detection, the jam signal and binary exponential backoff.

The earlier Ethernet Cross-Concept MCQs set owns bridges, VLANs, spanning tree, switching domains and frame-payload NATs. This set stays with IEEE 802.3 standards, rate families, link negotiation, IPv4 multicast mapping and classic collision handling.

Keep this map beside the wider GATE CS exam preparation route when revising Computer Networks.

Ethernet and IEEE 802.3 basics MCQs

Question 1

Tagged: UP Police, Computer Science, Paper 2 - Subject Oriented, 2018

Ethernet is also known as:

• 803.2

• 802.11b

• 802.3

• 802.5

Answer: 802.3, the third option. IEEE 802.3 is the standards family associated with Ethernet. IEEE 802.11 covers wireless LANs, IEEE 802.5 is associated with Token Ring, and 803.2 is not the requested IEEE LAN designation.

Question 2

Tagged: UGC NET, Paper I, June 2025

Which of the following is an example of IEEE 802.3?

• LAN

• MAN

• WAN

• PAN

Answer: LAN, the first option. IEEE 802.3 specifies Ethernet LAN technologies, so LAN is the intended category among these choices. This does not mean that every possible LAN technology is Ethernet; the stem asks for the narrower IEEE 802.3 mapping.

Question 3

What is Ethernet?

• A collision-detection protocol

• A protocol used by many wired LANs

• A protocol used for address translation

• A security protocol

Answer: A protocol used by many wired LANs, the second option. Ethernet is a wired LAN technology family, so it covers more than collision detection alone. CSMA/CD is one historical shared-medium access mechanism, while address translation and security perform different functions.

Ethernet evolution and speed MCQs

Question 4

Tagged: TPSC, Computer Science, Assistant Programmer, 2025

What is the maximum data transfer rate of Gigabit Ethernet?

• 100 Mbps

• 1 Gbps

• 10 Gbps

• 1 Tbps

Answer: 1 Gbps, the second option. The unit conversion is 1 Gbps = 1000 Mbps. That separates Gigabit Ethernet from Fast Ethernet at 100 Mbps and 10 Gigabit Ethernet at 10 Gbps.

Question 5

Tagged: UGC NET, Computer Science, Paper 2 (August), 2016

Consider the following statements : A. High speed Ethernet works on optic fiber. B. A point to point protocol over Ethernet is a network protocol for encapsulating PPP frames inside Ethernet frames. C. High speed Ethernet does not work on optic fiber. D. A point to point protocol over Ethernet is a network protocol for encapsulating Ethernet frames inside PPP frames. Which of the following is correct ?

• A and B are true; C and D are false.

• A and B are false; C and D are true.

• A, B, C and D are true.

• A, B, C and D are false.

Answer: A and B are true; C and D are false, the first option. Check the statements independently. High-speed Ethernet can use optical fibre, and PPPoE encapsulates PPP frames inside Ethernet frames. C contradicts A, while D reverses the encapsulation direction stated in B.

Ethernet hubs and auto-negotiation MCQs

Question 6

Tagged: Indian Space Research Organization, 2007, and BEL, 2007

An Ethernet hub

• functions as a repeater

• connects to a digital PBX

• connects to a token-ring network

• functions as a gateway

Answer: functions as a repeater, the first option. A hub repeats an incoming signal to its other ports. It does not learn MAC addresses or route between networks, and the gateway, PBX and Token Ring choices assign roles that a hub does not perform.

Question 7

Tagged: Indian Space Research Organization, Computer Science, 2014

A mechanism or technology used in Ethernet by which two connected devices choose common transmission parameters such as speed, duplex mode and flow control is called

• Autosense

• Synchronization

• Pinging

• Auto negotiation

Answer: Auto negotiation, the fourth option. Auto-negotiation lets two link partners agree on supported settings such as speed and duplex. Pinging tests IP reachability, while Autosense and Synchronization do not name the Ethernet link-parameter mechanism described here.

Ethernet MAC addressing and multicast MCQs

Question 8

Tagged: Indian Space Research Organization, Computer Science, 2009

Which of the following is a MAC address?

• 192.166.200.50

• 00056A:01A01A5CCA7FF60

• 568, Airport Road

• 01:A5:BB:A7:FF:60

Answer: 01:A5:BB:A7:FF:60, the fourth option. It contains six hexadecimal octets, so its length is 6 x 8 = 48 bits. The first option uses dotted-decimal IP-style notation, the second does not match the six-octet form, and the third is a postal address.

Question 9

Tagged: Indian Space Research Organization, Computer Science, 2014

Which of the following is not a valid multicast MAC address?

• 01:00:5E:00:00:00

• 01:00:5E:00:00:FF

• 01:00:5E:00:FF:FF

• 01:00:5E:FF:FF:FF

Answer: 01:00:5E:FF:FF:FF, the fourth option. For the IPv4 multicast mapping tested here, the Ethernet prefix is 01:00:5E, and the next octet must remain from 00 to 7F because only the lower 23 bits vary. FF in that position exceeds the valid range, while the first three options remain inside it. The earlier DLL Overview and MAC MCQs set owns layer placement, six-octet formatting and I/G-bit classification. This Ethernet set applies the narrower IPv4 multicast prefix range.

Ethernet CSMA/CD, jam signal and backoff MCQs

Question 10

Which of the following is true about jamming signals in Ethernet?

• Jamming signals are sent to resolve collisions by padding frames to the required size.

• Jamming signals are only used in full-duplex communication.

• Jamming signals help notify all stations about a collision.

• Jamming signals increase the bandwidth of Ethernet links.

Answer: Jamming signals help notify all stations about a collision, the third option. In shared half-duplex Ethernet, a station detecting a collision sends a jam signal so every participant recognises the event before backoff. It does not pad a short frame or increase bandwidth, and full-duplex switched links do not use CSMA/CD collision handling.

Question 11

Tagged: GATE, Computer Science, Set 2, 2016

In an Ethernet local area network, which one of the following statements is TRUE?

• A station stops to sense the channel once it starts transmitting a frame.

• The purpose of the jamming signal is to pad the frames that are smaller than the minimum frame size.

• A station continues to transmit the packet even after the collision is detected.

• The exponential backoff mechanism reduces the probability of collision on retransmissions.

Answer: The exponential backoff mechanism reduces the probability of collision on retransmissions, the fourth option. A station keeps monitoring the shared medium while transmitting. After detecting a collision, it aborts normal frame transmission, sends the jam sequence and chooses a random backoff. The expanding choice range after repeated collisions reduces the chance that the same stations transmit together again.

Question 12

Stations Alpha and Zeta attempt to transmit a frame over Ethernet, but they collide. With what probability does Zeta win the first backoff race?

• 0.25

• 0.625

• 0.125

• 0.375

Answer: 0.25, the first option. After the first collision, each station independently chooses a backoff value from {0, 1}, with probability 1/2 for each value. The four equally likely ordered outcomes (Zeta, Alpha) are (0,0), (0,1), (1,0) and (1,1). Zeta wins only in (0,1); equal values are ties, not wins.

Therefore,

P(Zeta wins) = P(Zeta=0) x P(Alpha=1) = 1/2 x 1/2 = 1/4 = 0.25.

A common slip is to discard the tied outcomes and compute the probability only among decisive races. The answer expected here is the unconditional probability for this first race, so all four outcomes stay in the denominator. The earlier CSMA/CD MCQs set owns collision-window calculations and unequal multi-stage backoff races. This Ethernet set isolates the first two-slot race.

Ethernet IEEE 802.3 MCQs: traps, coverage and the next step

Correct these six traps before you leave the topic:

• 802.3 is Ethernet; 802.11 is wireless LAN.

• 1 Gbps = 1000 Mbps.

• A hub repeats signals; it does not learn addresses or route packets.

• Auto-negotiation chooses common link parameters.

• A MAC address has six hexadecimal octets.

• A jam signal announces a collision; binary exponential backoff randomises retransmission.

Ethernet questions test standard definitions, evolution and speed, device negotiation, MAC addressing and collision handling. Reattempt the questions by concept bucket, then explain why each distractor belongs to a different layer, standard or collision rule.

The short retrieval sequence is standard -> rate -> device -> address -> collision response. Keep its two numerical anchors visible: 1 Gbps = 1000 Mbps and 1/2 x 1/2 = 0.25. For broader Computer Networks study in a structured course sequence, use GATE Guidance by Sanchit Sir as the next step.