1.1 - Understanding the OSI Model

Flashcards covering the Seven Layers of the OSI Model, related protocols, and troubleshooting concepts based on the CompTIA Network+ N10-009 lecture.

OSI model

Open Systems Interconnection Reference Model; a broad overview used in IT to describe the process data takes as it traverses a network.

All People Seem To Need Data Processing

A mnemonic used to remember the seven layers of the OSI model from top (Application) to bottom (Physical).

Layer 1 - Physical layer

The layer describing physical signals sent through cables, fibers, or wireless networks; involves troubleshooting with loopback tests and checking for interference.

Layer 2 - Data link layer

The fundamental layer for communication between two devices, often called the switching layer or the MAC address layer.

MAC address

Media Access Control address; the hardware address of a network adapter card, also known as the Data Link Control (DLC) address.

EUI

Extended Unique Identifiers; associated with OSI layer 2, examples include EUI-48 and EUI-64.

Layer 3 - Network layer

The routing layer where routers use destination IP addresses to determine the next hop and fragment frames into smaller pieces if necessary.

Layer 4 - Transport layer

Referred to as the post office layer, it is responsible for transporting information between devices using protocols like TCP and UDP.

TCP

Transmission Control Protocol; a layer 4 protocol responsible for getting all information within IP packets from one device to another.

UDP

User Datagram Protocol; a layer 4 protocol used to transport data across the network.

Layer 5 - Session layer

Provides communication management between point A and point B, including the initiation, stopping, restarting, or tunneling of session data.

Layer 6 - Presentation layer

The layer responsible for character encoding and application encryption or decryption, such as SSL or TLS, prior to displaying data.

Layer 7 - Application layer

The top layer where users interact with application protocols such as HTTP, HTTPS, FTP, DNS, and POP$3$.