CompTIA Network+ N10-009 OSI Model OB 1.1

OSI Model

A model made up of seven layers each with its own software and hardware created to achieve interoperability of diverse devices

Application Layer

Layer 7 - Generates data to be transmitted

Presentation Layer

Layer 6 - Gets the data ready for the application layer by converting

Session Layer

Layer 5 - Provides dialog control by allowing multiple persistent connections from different sources to be properly combined or synchronized

Transport Layer

Layer 4 - Handles the End-to-End communication either via TCP for connection-oriented communication or UDP for connectionless communication

Network Layer

Layer 3 - Provides communication between different networks via IP addresses

Data Link Layer

Layer 2 - Provides communication within the same network via MAC addresses

Physical Layer

Layer 1 - Converts bits into electrical signal over copper cables

Encapsulation/Deencapsulation

How data moves throughout the OSI Model and is encapsulated

Full Duplex

Send and receive data at the same time (e.g.

Half Duplex

Send and receive data one at a time (e.g.

Simplex

Only send or receive data (e.g.

Well Known ports

0-1023

Registered Ports

1024-49151

Dynamic or Private Ports

49152-65535

Logical Link Layer (LLC)

Sublayer of Data Link Layer - Provides flow control (prevent one machine from overwhelming the other machine) and error control (error detection)

Media Access Control (MAC)

Sublayer of Data Link Layer - Controls how devices on the network are able to transmit data