Network+ OSI Model Overview

Vocabulary practice flashcards covering the components, protocols, and characteristics of the seven layers of the OSI model based on the lecture.

OSI Model

Open Systems Interconnection Reference model; a conceptual model used in information technology to describe the broad process that 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 (Layer 7) to bottom (Layer 1): Application, Presentation, Session, Transport, Network, Data link, and Physical.

Layer 1 (Physical Layer)

The bottom OSI layer responsible for transmitting physical signals across network cables, fibers, or wireless connections, where troubleshooting includes checking hardware adapters and running loopback tests.

Layer 2 (Data Link Layer)

The OSI layer that serves as the fundamental layer to communicate between two devices on a network, commonly known as the switching layer or MAC address layer.

MAC Address

Media Access Control address; the physical hardware address assigned to network interface cards, such as ethernet or wireless adapters, operating at Layer 2.

Extended Unique Identifier (EUI)

A Layer 2 addressing format associated with data link identification, appearing as EUI-48 and EUI-64 addresses.

Layer 3 (Network Layer)

The OSI layer responsible for routing traffic across networks using destination IP addresses and subnet masks to determine the next hop.

Fragmentation

The Layer 3 process of cutting frames into smaller pieces so they can traverse networks requiring smaller frame sizes, followed by reassembling them on the destination side.

Layer 4 (Transport Layer)

The OSI layer responsible for transporting data between devices across the network—often referred to as the 'post office layer'—utilizing TCP and UDP ports.

Transmission Control Protocol (TCP)

A Layer 4 transport protocol commonly responsible for breaking data down into smaller segments and moving information within IP packets across the network.

User Datagram Protocol (UDP)

A transport protocol operating at Layer 4 of the OSI model used to transport information between devices.

Layer 5 (Session Layer)

The OSI layer providing communication management between point A and point B, handling the initiation, termination, and restarting of sessions, as well as control protocols and tunneling.

Layer 6 (Presentation Layer)

The OSI layer responsible for formatting data for human viewing, including character encoding as well as application-level encryption and decryption (such as SSL and TLS).

Layer 7 (Application Layer)

The top layer of the OSI model where users view and interact directly with applications, utilizing application protocols such as HTTP, HTTPS, FTP, DNS, and POP3.

Wireshark

A network protocol decode application that displays captured network packets in three windows: a frame-by-frame breakdown, a frame detail view, and a hexadecimal/ASCII data view.

Port 443

A destination TCP port number operating at Layer 4 that designates encrypted communication using HTTPS.