CompTIA Network+ N10-009

Current Ethernet Specifications

Covering Ethernet fundamentals, CSMA/CD, collision and broadcast domains, MAC addressing, binary/hex conversions, and physical layer cabling standards.

1.5 Domain 1 Objective

802.3 Standard

20 Quiz Qs

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01 · Fundamentals

Ethernet Basics & CSMA/CD

Ethernet is a contention media-access method that allows all hosts on a network to share the same bandwidth. It uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) to manage traffic and reduce collisions.

// Exam Objectives Covered

Domain 1.0: Networking Concepts
1.5 Compare and contrast transmission media and transceivers
802.3 standards (Coaxial, UTP, Fiber)
CSMA/CD operation and collision domains
Half-duplex vs. Full-duplex communication
MAC addressing and frame structure

Collision Domain

A network scenario where one device sending a packet forces all other devices on the same physical segment to pay attention. If two devices transmit simultaneously, a collision occurs, requiring retransmission.

Broadcast Domain

Refers to the set of all devices on a network segment that hear all broadcasts sent on that segment. Routers break up broadcast domains, while switches break up collision domains.

CSMA/CD

Carrier Sense Multiple Access with Collision Detection. Devices check for a digital signal before transmitting. If a collision is detected, a jam signal is sent, and devices wait a random backoff time before retrying.

02 · Data Link Layer

Addressing & Framing

At the Data Link layer, Ethernet is responsible for MAC addressing (hardware addressing) and framing packets from the Network layer for transmission.

MAC Addressing

A 48-bit (6-byte) address burned into the NIC, written in hexadecimal.

OUI (Organizationally Unique Identifier): The first 24 bits (3 bytes) assigned by the IEEE to the manufacturer.
Unique Identifier: The last 24 bits (3 bytes) assigned by the manufacturer.

I/G and L/G Bits

I/G (Individual/Group): The first bit. If 0, it's a unicast. If 1, it's a broadcast/multicast.

L/G (Local/Global): The second bit. If 0, it's globally unique (BIA). If 1, it's locally administered.

Ethernet Frame Structure

Preamble: 7 bytes. Alternating 1,0 pattern for timing synchronization.
SFD: 1 byte. Start of Frame Delimiter (10101011).
Destination Address (DA): 6 bytes. Receiving MAC address.
Source Address (SA): 6 bytes. Sending MAC address.
Type/Length: 2 bytes. Identifies the upper-layer protocol (e.g., 0x0800 for IPv4).
Data: 64-1500 bytes. The payload.
FCS: 4 bytes. Frame Check Sequence for CRC error detection.

03 · Physical Layer

IEEE 802.3 Standards

Ethernet standards define speed, distance, and media types. It is crucial to know the common copper and fiber standards for the exam.

100BaseTX

100 Mbps. Uses Category 5 UTP (2 pairs). Maximum distance: 100 meters. Physical star, logical bus.

1000BaseT

1000 Mbps (1 Gbps). Uses Category 5e+ UTP (4 pairs). Maximum distance: 100 meters.

10GBaseT

10 Gbps. Uses Category 6a+ UTP. Maximum distance: 100 meters. Most economical way to run 10G over copper.

1000BaseSX

1000 Mbps. Multimode fiber (MMF). 850nm laser. Max distance: 550 meters.

10GBaseSR

10 Gbps. Multimode fiber (MMF). 850nm laser. Max distance: 300 meters.

10GBaseLR

10 Gbps. Single-mode fiber (SMF). 1310nm laser. Max distance: 10 kilometers.

10 · Written Lab

Practice Written Lab

Fill in the correct value for the decimal, binary, and hexadecimal conversions. Type your answer and press Enter or click outside the field to check.

What is the decimal value equivalent to the hexadecimal value 0xF?

What is the binary representation of the decimal number 5?

Hint: 4 bits

What is the hexadecimal representation of the decimal number 14?

What is the decimal value of the binary number 0111?

What binary number is equivalent to the decimal value 28?

Hint: 16 + 8 + 4

What is the hexadecimal value of the decimal number 16?

What is the decimal equivalent of the hexadecimal value 0xb?

What is the binary representation of the hexadecimal value 0xE?

What is the binary representation of the decimal number 177?

Hint: 8 bits

What is the hexadecimal representation of the decimal number 208?

Hint: 13 and 0

11 · Review Quiz

Test Your Knowledge

20 review questions covering all the chapter material. Select the best answer for each question.

Question 1 of 20

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