OSI and TCP/IP Layers

OSI Layer 1

Physical

OSI Layer 2

Data Link

OSI Layer 3

Network

OSI Layer 4

Transport

OSI Layer 5

Session

OSI Layer 6

Presentation

OSI Layer 7

Application

TC/IP Layer 1

Network Access

TCP/IP Layer 2

Internet

TCP/IP Layer 3

Transport

TCP/IP Layer 4

Application

Application Layer (description)

Serves as the window for the users and application processes to access the network services.

Presentation Layer (description)

Formats the data to be presented to the Application layer. It can be viewed as the translator for the network.

Session Layer (description)

Allows session establishment between processes running on different stations.

Transport Layer (description)

Ensures that messages are delivered error free, in sequence and with no losses or duplication.

Network Layer (description)

Controls the operations of the subnet, deciding which physical path the data takes.

Data Link Layer (description)

Provides error-free transfer of data frames from one node to another over the physical layer.

Physical Layer (description)

Concerned with the transmission and reception of the unstructured raw bit stream over the physical medium.