OSI MODEL OBJ. 1.1

OSI Model

Open Systems Interconnection Model

Reference Model

Used to categorize the functions of a network in the OSI Model during troubleshooting efforts

In what order are the layers?

Bottom to top

Pneumonic to memorize the 7 layers

Please - Physical

Do - Data Link

Not - Network

Throw - Transport

Sausage - Session

Pizza -Presentation

Away - Application

What is Data called at layers 5 (session), 6 (presentation) and 7 (application) ?

Data

What is data called at the 4th (transport) layer?

Segments

What is data called at the 3rd (network) layer?

Packet

What is data called at the 2nd (Data Link) layer?

Frames

What is data called at the 1st (physical) layer?

Bits

Pneumonic to Memorize Data Types

Do - Data

Some - Segments

People - Packets

Fear - Frames

Birthdays - Bits

Layer 1

Physical

Layer 2

Data Link Layer

Layer 3

Network Layer

Layer 4

Transport Layer

Layer 5

Session Layer

Layer 6

Presentation Layer

Layer 7

Application Layer

Encapsulation

Process of wrapping data with protocol information at each layer of the OSI model as it passes down the networking stack

Decapsulation

Process of removing that protocol information layer by layer as the data unpacks itself on the receiving end as it moves up the OSI model.