Ethernet Fundamentals

CompTIA+ Network learning

Layer 2

Layer 2 refers to the data link layer of the OSI model, which is responsible for the reliable transmission of data between adjacent network nodes.

Ethernet fundamentals

This refers to the basic principles and concepts of Ethernet, a widely used networking technology for local area networks (LANs).

OSI model

The OSI model is a conceptual framework that standardizes the functions of a communication system into seven different layers, with layer 2 being the data link layer.

Domain

In the context of this paragraph, a domain refers to a specific area or topic within the field of networking.

Networking fundamentals

This domain focuses on the foundational concepts and principles of networking, including protocols, addressing, and network models.

Network implementations

This domain covers the practical aspects of implementing and configuring network devices and technologies.

Network security

This domain deals with the protection of network resources and data from unauthorized access, attacks, and threats.

Network troubleshooting

This domain involves identifying and resolving issues or problems that may arise in a network, such as connectivity issues or performance problems.

Objectives

These are specific goals or learning outcomes that students are expected to achieve in the course. The objectives mentioned in the paragraph are related to different domains and cover topics such as cable types, device comparison, configuration, security, and troubleshooting.

Cables and connectors

This objective focuses on understanding the different types of cables and connectors used in networking and knowing which ones are appropriate for specific solutions.

Network devices

This objective involves comparing and contrasting various network devices, including their features and where they should be placed in a network.

Ethernet switching features

This objective relates to configuring and deploying common features of Ethernet switches, such as VLANs, spanning tree protocol, and port security.

Remote access methods

This objective deals with comparing and contrasting different methods of remote access to a network, as well as the security implementations associated with them.

Troubleshooting networking issues

This objective focuses on the ability to identify and resolve general networking issues, such as connectivity problems, performance degradation, or misconfigurations.

CSMA/CD

Stands for carrier sense multiple access with collision detection. It is a method used by Ethernet to prevent collisions in a network.

Carrier Sense

The process of listening to the network to determine if a signal is already being transmitted.

Multiple Access

Refers to the ability of multiple devices to access, listen to, and transmit on the network at the same time.

Collision Detection

The process of detecting a collision when two devices transmit at the same time and deciding who gets to transmit first.

Random Back Off Timer

A timer used by Ethernet devices to wait for a random amount of time before retransmitting after a collision is detected.

Collision Domain

An area of the network where devices share the same network segment and may experience collisions.

Half-Duplex Mode

Mode of operation in which devices can either listen or transmit, but not both at the same time.

Full-Duplex Mode

Mode of operation in which devices can listen and transmit simultaneously, increasing bandwidth and eliminating collisions.

Ethernet Standards

Different classifications of Ethernet, represented by a number, the word "base," and one or two letters, indicating the speed and distance capabilities of the network.

Ethernet

A standard for connecting devices in a local area network (LAN) using copper or fiber optic cables.

10BASE-T

An Ethernet standard that operates at 10 megabits per second over CAT 3 cables.

100BASE-TX

An Ethernet standard that operates at 100 megabits per second over CAT 5 cables.

1000BASE-T

An Ethernet standard that operates at 1,000 megabits per second (one gigabit per second) over CAT 5e or CAT 6 cables.

10GBASE-T

An Ethernet standard that operates at 10 gigabits per second over CAT 6, CAT 6a, and CAT 7 cables.

40GBASE-T

An Ethernet standard that operates at 40 gigabits per second over CAT 8 cables.

Bandwidth

The capacity of a network to transmit data, measured in bits per second.

CAT 8

A type of copper cable that can transmit data at 40 gigabits per second over a distance of 30 meters.

CAT 6

A type of copper cable that can transmit data at 10 gigabits per second over a distance of 55 meters (or 100 meters at 1 gigabit per second).

Fiber optic cables

Cables that use light signals to transmit data over long distances.

100BASE-FX

An Ethernet standard that operates at 100 megabits per second over multimode fiber and can reach a distance of up to two kilometers.

100BASE-SX

An Ethernet standard that operates at 100 megabits per second over multimode fiber and can reach a distance of up to 300 meters.

1000BASE-SX

An Ethernet standard that operates at 1,000 megabits per second (one gigabit per second) over multimode fiber and can reach distances of 200 to 550 meters.

1000BASE-LX

An Ethernet standard that operates at 1,000 megabits per second (one gigabit per second) over single mode or multimode fiber and can reach distances of up to five kilometers (or 550 meters with multimode fiber).

10GBASE-SR

An Ethernet standard that operates at 10 gigabits per second over multimode fiber and has a maximum distance of about 400 meters.

10GBASE-LR

An Ethernet standard that operates at 10 gigabits per second over single mode fiber and can reach distances of up to 10 kilometers.

Single mode fiber

A type of fiber optic cable that can transmit data over long distances, typically in kilometers.

Multimode fiber

A type of fiber optic cable that can transmit data over shorter distances, typically in hundreds of meters.

S is not single

A memory aid to help remember that Ethernet standards with "S" in the name (e.g., 100BASE-SX, 1000BASE-SX, 10GBASE-SR) use multimode fiber.

Routers

Network devices that connect multiple networks and forward data packets between them.

Switches

Network devices that connect multiple devices within a network and forward data packets between them.

Hub

A networking device that receives data from one port and broadcasts it to all other ports.

Active Hub

Similar to a regular hub, but it boosts the signal before broadcasting it to overcome cable length limitations.

Passive Hub

A hub that does not boost the signal, causing it to count towards the cable length limitation.

Twisted Pair Cabling

A type of network cable with pairs of wires twisted together to reduce interference.

100-meter Limitation

The maximum distance that twisted pair cabling can reliably transmit data without signal degradation.

Collision Domain

A network segment where network devices compete to transmit data, leading to collisions and reduced network performance.

Bridge

A networking device that analyzes MAC addresses in data frames and forwards them based on the destination MAC address.

Switch

A layer 2 device that connects multiple network segments together, breaking up collision domains and improving network performance and security.

Broadcast Domain

A group of devices that receive broadcast messages sent by any device within the same domain.

MAC Address

A unique identifier assigned to network devices at the factory, used for communication within a network.

Switch

A layer 2 device that operates based on MAC addresses and is used to connect devices within a local network.

Router

A layer 3 device that is used to connect dissimilar networks, such as an internal network and the Internet, and makes routing decisions based on logical network information like IP addresses.

Layer 3 Switch

Also known as a multilayer switch, it is a layer 3 device that combines the functions of a switch and a router, allowing it to connect multiple networks together and perform routing functions.

Broadcast Domain

A network area where broadcast messages are sent and received.

Collision Domain

A network area where network devices contend for access to the network medium, and collisions may occur when multiple devices transmit data simultaneously.

Hub

A device that operates at layer 1 and allows multiple devices to connect and share a single network segment, resulting in a single collision and broadcast domain.

Bridge

A device that operates at layer 2 and connects multiple network segments, creating separate collision domains for each port while still having a single broadcast domain.

Media Converter

A device used to convert signals between different types of media, such as fiber to ethernet or coaxial cable to ethernet.

Wide Area Network (WAN)

A network that connects devices over a large geographical area, such as the Internet.

Local Area Network (LAN)

A network that connects devices within a limited geographical area, such as an office or home network.

Simple switch

A basic device that allows network connections to be passed to multiple ports.

Wireless access point

A device that allows wireless devices to connect to a wired network.

Combination device

A device that combines multiple functions, such as a wireless access point, router, and switch, into one device.

Media converter

A device that converts signals from one type of media to another, such as converting from Ethernet to wireless.

Link aggregation

Combining multiple physical connections into a single logical connection to increase bandwidth and alleviate congestion.

Power over Ethernet (PoE)

The ability to supply electrical power to devices over an Ethernet cable, eliminating the need for separate power cables.

Port monitoring

The process of analyzing packet flow over a network by mirroring traffic from multiple ports to a single port for analysis.

User authentication (802.1x)

A security feature that requires users to authenticate themselves before gaining access to a network.

Key distribution

The process of distributing an authorized key from the authentication server to the authenticator, which is then used to encrypt traffic between the switch and the client.

Symmetric encryption tunnel

A secure connection created between the switch and the PC using the same key, allowing for the encryption of all data transmitted.

Management access

The ability to configure and manage switches either remotely using SSH or locally using a console port.

Secure Shell (SSH)

A remote administration program that operates over port 22, allowing for secure remote management of a switch over a network.

Console port

A physical port on a switch that allows for local configuration and management using an RS 232 serial cable, also known as a rollover cable.

Out of band management network

A separate network configuration used for connecting to and configuring devices, providing additional security by separating management devices from the data network.

First-hop redundancy

The use of protocols like HSRP (Hot Standby Router Protocol) to create a virtual IP address and virtual MAC address, ensuring redundancy and failover in layer 3 switches and routers.

MAC filtering

The process of allowing or denying traffic based on a device's MAC address, used to improve security in layer 2 switches.

Traffic filtering

The process of allowing or denying traffic based on IP addresses or ports, used in layer 3 and layer 4 switches or routers.

Quality of service (QoS)

The prioritization and forwarding of network traffic based on different priority markings, ensuring higher priority traffic, such as voice traffic, is given preference.

Spanning Tree Protocol (STP)

A protocol that prevents loops in network traffic and allows for redundant links between switches, ensuring network availability and preventing network corruption.

Shortest Path Bridging (SPB)

An alternative to STP used in larger network environments, providing similar functionality but not covered in depth in the Network Plus exam.

Mac address tables

Tables used by switches to store and associate MAC addresses with specific ports.

Switching loop

A loop created when network switches continuously forward broadcast frames to each other, leading to a broadcast storm and network congestion.

Broadcast storm

A situation where a network becomes overwhelmed with excessive broadcast traffic due to a switching loop.

Spanning Tree Protocol (STP)

A protocol used to prevent switching loops by creating a loop-free topology and selecting a root bridge.

Root bridge

The elected switch that serves as the reference point for the spanning tree protocol and has the lowest bridge ID.

Bridge ID

A combination of a priority value and a MAC address used to determine the root bridge in the spanning tree protocol.

Root port

The port on a non-root bridge that is closest to the root bridge in terms of cost and port number.

Designated port

The port on a network segment that is closest to the root bridge in terms of cost and is responsible for forwarding traffic.

Non-designated port

A port on a non-root bridge that is not designated for forwarding traffic and acts as a stop sign.

Blocking state

The initial state of a non-designated port in the spanning tree protocol where it does not forward traffic and acts as a stop sign.

Listening state

The state in the spanning tree protocol where a port starts populating the MAC address table and learning, but does not forward frames yet.

Learning state

The state in the spanning tree protocol where a port processes bridge protocol data units (BPDUs) and determines its role in the spanning tree.

Forwarding state

The state in the spanning tree protocol where a port starts forwarding frames and takes on the role of either a designated port or a root port.

Switch states

Switches go through four states - blocking, listening, learning, and forwarding - when a neighboring switch goes down.

Link cost

The link cost is associated with the speed of a given link. Lower link speeds have higher costs, while higher link speeds have lower costs.

VLAN (Virtual Local Area Network)

VLANs allow for the logical separation of switch ports into different broadcast domains, providing additional security and efficiency.