It is primarily used today as a teaching tool.

It conceptually divides computer internet architecture into 7 layers in a logical progression.

The lower layers deal with electrical signals, chunks ofbinary data, and routing of these data across networks.

Illustration of Physical Layer, showing repeaters, ethernet cables and hubs, and token ring networks

Lifewire / Colleen Tighe

Examples of layer 1 technologies includeEthernet cablesandhubs.

connection Layer

The connection layer adds the concept of routing above the Data Link layer.

Otherwise, the web connection layer updates the destination address and pushes the frame down to the lower layers.

Illustration of Data Link Layer with destination and source address, media access control, and frame footer

Lifewire / Colleen Tighe

To support routing, the online grid layer maintains logical addresses such asIP addressesfor devices on the online grid.

The data pipe layer also manages the mapping between these logical addresses and physical addresses.

Presentation Layer

The Presentation layer has the simplest function of any piece of the OSI model.

Illustration of Network Layer

Lifewire / Colleen Tighe

program Layer

The program layer supplies connection services to end-user applications.

web link services are protocols that work with the user’s data.

This layer 7 provides data to (and obtains data from) the Presentation layer.

Transport Layer diagram

Lifewire / Colleen Tighe

Illustration of session layer showing a series of highway overpasses

Lifewire / Colleen Tighe

Illustration of the presentation layer, which looks like a movie projector

Lifewire / Colleen Tighe

Illustration of the Application Layer as a picture of a cat on a person’s computer

Lifewire / Colleen Tighe